¥ / ANNALS OF BOTANY VOL. XVII ©xf orb PRINTED AT THE CLARENDON PRESS BY HORACE HART, M.A. PRINTER TO THE UNIVERSITY Annals of Botany Wv EDITED BY ISAAC BAYLEY BALFOUR, M.A., M.D., F.R.S. KING’S BOTANIST IN SCOTLAND, PROFESSOR OF BOTANY IN THE UNIVERSITY AND KEEPER OF THE ROYAL BOTANIC GARDEN, EDINBURGH D. H. SCOTT, M.A., Ph.D., F.R.S. HONORARY KEEPER OF THE JODRELL LABORATORY, ROYAL BOTANIC GARDENS, KEW AND WILLIAM GILSON FARLOW, M.D. PROFESSOR OF CRYPTOGAMIC BOTANY IN HARVARD UNIVERSITY, CAMBRIDGE, MASS., U.S.A. ASSISTED BY OTHER BOTANISTS VOLUME XVII With Forty Plates and thirty-two Figures in the Text London HENRY FROWDE, M.A., AMEN CORNER, E.C. OXFORD: CLARENDON PRESS DEPOSITORY, 116 HIGH STREET 1903 m 5H z . h^o\ CONTENTS. No. LXV, January, 1903. Sargant, Miss E. — A Theory of the Origin of Monocotyledons, founded on the Structure of their Seedlings. With Plates I- VII, and ten Figures in the Text ......... Darwin, F., and Pertz, Miss D. F. M. — On the artificial Production of Rhythm in Plants. With a note on the position of maximum helio- tropic Stimulation. With four Figures in the Text Salmon, E. S. — A Monograph of the Genus Streptopogon, Wils. With Plates VIII, IX, and X Marloth, R. — Some recent Observations on the Biology of Roridula. With a Figure in the Text ......... Sprague, T. A. — On the Heteranthus Section of Cuphea (Lythraceae). With Plate XI Barker, B. T. P. — The Morphology and Development of the Ascocarp in Monascus. With Plates XII and XIII . . .... Vines, S. H. — Proteolytic Enzymes in Plants ...... NOTES. Hill, A. W. — Notes on the Histology of the Sieve-tubes of certain Angio- sperms ............ Crossland, C. — Note on the Dispersal of Mangrove Seedlings. With a Figure in the Text ......... Cavers, F.— Explosive Discharge of Antherozoids in Fegatella conica. With a Figure in the Text ......... Fritsch, F. E. — Algological Notes. IV. Remarks on the periodical Development of the Algae in the artificial Waters at Kew Bower, F. O. — Note on abnormal Plurality of Sporangia in Lycopodium rigidum, Gmel. With a Figure in the Text .... No. LXVI, March, 1903. Allen, C. E. — The Early Stages of Spindle-Formation in the Pollen-Mother- Cells of Larix. With Plates XIV and XV Willis, J. C., and Burkill, I. H. — Flowers and Insects in Great Britain. Part II. Observations on the Natural Orders Dipsaceae, Plumba- ginaceae, Compositae, Umbelliferae, and Cornaceae, made in the Clova Mountains .......... page 1 93 107 I 5 I 159 167 237 265 267 270 274 278 281 3i3 VI Contents . Miyake, K. — On the Development of the Sexual Organs and Fertilization in Picea excelsa. With Plates XVI and XVII .... Howard, A. — On some Diseases of the Sugar-Cane in the West Indies. With Plate XVIII Hill, T. G., and Freeman, Mrs. W. G. — The Root-Structure of Dioscorea prehensilis. With Plate XIX and a Figure in the Text . Arber, E. A. N. — On the Roots of Medullosa anglica. With Plate XX Thiselton-Dyer, Sir W. T. — Morphological Notes. IX. A Kalanchoe Hybrid. With Plates XXI-XXIII NOTES. Hemsley, W. B., and Rose, J. N. — Diagnoses Specierum Generis Juliania, Schlecht., Americae tropicae ........ Hope, C. W. — Note to Article in the Annals of Botany, Vol. xvi, No. 63, September, 1902, on ‘ The “ Sadd ” of the Upper Nile ’ No. LXVII, June, 1903. Oliver, F. W. — The Ovules of the older Gymnosperms. With Plate XXIV and a Figure in the Text ........ Davis, B. M. — The Origin of the Archegonium. With two Figures in the Text Tansley, A. G., and Chick, Miss E. — On the Structure of Schizaea malac- cana. With Plates XXV and XXVI and a Figure in the Text Boodle, L. A. — Comparative Anatomy of the Hymenophyllaceae, Schizae- aceae and Gleicheniaceae. IV. Further Observations on Schizaea. With three Figures in the Text Willis, J. C., and Burkill, I. H. — Flowers and Insects in Great Britain. Part III. Observations on the most Specialized Flowers of the Clova Mountains .......... Dale, Miss E. — Observations on Gymnoascaceae. With Plates XXVII and XXVIII Vines, S. H. — Proteolytic Enzymes in Plants (II) NOTES. Pearson, H. H. W. — The Double Pitchers of Dischidia Shelfordii, sp. nov. Bower, F. O. — Studies in the Morphology of Spore-producing Members. No. V. General Comparisons, and Conclusion .... Oliver, F. W., and Scott, D. H. — On Lagenostoma Lomaxi, the Seed of Lyginodendron No. LXVIII, September, 1903. Fritsch, F. E. — Further Observations on the Phytoplankton of the River Thames Two Fungi, parasitic on species of Tolypothrix (Resticu- laria nodosa, Dang, and R. Boodlei, n. sp.). With Plate XXIX . page 35 1 373 4*3 4 2 5 435 443 446 45i 477 493 539 57i 597 617 618 625 631 649 Contents. vii PAGE Campbell, Douglas Houghton. — Studies on the Araceae. The Embryo- sac and Embryo of Aglaonema and Spathicarpa. With Plates XXX, XXXI, and XXXII 665 Gwynne-Vaughan, D. T. — Observations on the Anatomy of Solenostelic Ferns. Part II. With Plates XXXIII, XXXIV, and XXXV . 689 Hemsley, W. Botting.— On the Genus Corynocarpus, Forst. With descrip- tions of two new Species. With Plate XXXVI, and two Figures in the Text 743 Scott, Rina. — On the Movements of the Flowers of Sparmannia africana, and their Demonstration by means of the Kinematograph. With Plates XXXVII, XXXVIII, and XXXIX 761 Thiselton-Dyer, Sir W. T. — Morphological Notes. X. A proliferous Pinus Cone. With Plate XL 779 NOTES. Wigglesworth, Miss G. — The Cotyledons of Ginkgo biloba and Cycas revoluta. With a Figure in the Text 789 Stopes, Miss M. C. — The ‘ Epidermoidal ’ layer of Calamite Roots. With three Figures in the Text . 792 INDEX A. ORIGINAL PAPERS AND NOTES. PAGE Allen, C. E. — The Early Stages of Spindle-Formation in the Pollen- Mother- Cells of Larix. With Plates XIV and XV . . . . .281 Arber, E. A. N. — On the Roots of Mednllosa anglica. With Plate XX . 425 Barker, B. T. P. — The Morphology and Development of the Ascocarp in Monascus. With Plates XII and XIII . . . . . .167 Boodle, L. A. — Comparative Anatomy of the Hymenophyllaceae, Schizae- aceae and Gleicheniaceae. IV. Further Observations on Schizaea. With three Figures in the Text . . . ... . .511 Bower, F. O. — Note on abnormal Plurality of Sporangia in Lycopodium rigidum, Gmel. With a Figure in the Text 278 ^ Studies in the Morphology of Spore-producing Members. No. V. General Comparisons, and Conclusion . . . .618 Burkill, I. H., see Willis, J. C. Campbell, D. H. — Studies on the Araceae. The Embryo-sac and Embryo of Aglaonema and Spathicarpa. With Plates XXX, XXXI, and XXXII .665 Cavers, F. — Explosive Discharge of Antherozoids in Fegatella conica. With a Figure in the Text 270 Chick, Miss E., see Tansley, A. G. Crossland, C. — Note on the Dispersal of Mangrove seedlings. With a Figure in the Text ......... 267 Dale, Miss E. — Observations on Gymnoascaceae. With Plates XXVII and XXVIII 571 DARWIN, F., and Pertz, Miss D. F. M. — On the artificial Production of Rhythm in Plants. With a note on the position of maximum helio- tropic Stimulation. With four Figures in the Text ... 93 Davis, B. M. — The Origin of the Archegonium. With two Figures in the Text 477 Freeman, Mrs. W. G., see Hill, T. G. Fritsch, F. E. — Algological Notes. IV. Remarks on the periodical Development of the Algae in the artificial Waters at Kew . . 274 Further Observations on the Phytoplankton of the River Thames 631 Two Fungi, parasitic on Species of Tolypothrix (Resticu- laria nodosa, Dang, and R. Boodlei, n. sp.). With Plate XXIX . 649 Gwynne-Vaughan, D. T. — Observations on the Anatomy of Solenostelic Ferns. Part II. With Plates XXXIII, XXXIV, and XXXV . 689 Hemsley, W. B. — On the Genus Corynocarpus, Forst., with descriptions of two new Species. With Plate XXXVI and two Figures in the Text 743 Hemsley, W. B., and Rose, J. N.— Diagnoses Specierum Generis Juliania, Schlecht., Americae tropicae ........ 443 Hill, A. W. — Notes on the Histology of the Sieve-tubes of certain Angio- sperms 265 Index . ix PAGE Hill, T. G.,and Freeman, Mrs. W. G.—The Root-Structure ofDioscorea prehensilis. With Plate XIX and a Figure in the Text . Hope, C. W. — Note to Article in the Annals of Botany, Vol. xvi, No. 63, September, 1902, on ‘ The “ Sadd ” of the Upper Nile ’ . Howard, A. — On some Diseases of the Sugar-Cane in the West Indies. With Plate XVIII Marloth, R. — Some recent Observations on the Biology of Roridula. With a Figure in the Text Miyake, K. — On the Development of the Sexual Organs and Fertilization in Picea excelsa. With Plates XVI and XVII .... Oliver, F. W. — The Ovules of the older Gymnosperms. With Plate XXIV and a Figure in the Text ........ Oliver, F. W., and Scott, D. H.— On Lagenostoma Lomaxi, the Seed of Lyginodendron Pearson, H. H. W. — The Double Pitchers of Dischidia Shelfordii, sp. nov. Pertz, Miss D. F. M., see Darwin, F. Rose, J. N., see Hemsley, W. B. Salmon, E. S. — A Monograph of the Genus Streptopogon, Wils. With Plates VIII, IX, and X Sargant, Miss E. — A Theory of the Origin of Monocotyledons, founded on the Structure of their Seedlings. With Plates I- VII and ten Figures in the Text Scott, D. H., see Oliver, F. W. Scott, Rina. — O n the Movements of the Flowers of Sparmannia africana, and their Demonstration by means of the Kinematograph. With Plates XXXVII, XXXVIII, and XXXIX Sprague, T. A. — On the Heteranthus Section of Cuphea (Lythraceae). With Plate XI Stopes, Miss M. C. — The ‘ Epidermoidal ’ layer of Calamite Roots. With three Figures in the Text ........ Tansley, A. G., and Chick, Miss E. — On the Structure of Schizaea malac- cana. With Plates XXV and XXVI and a Figure in the Text Thiselton-Dyer, Sir W. T.— Morphological Notes. IX. A Kalanchoe Hybrid. With Plates XXI-XXIII Morphological Notes. X. A proliferous Pinus Cone. With Plate XL ....... Vines, S. H. — Proteolytic Enzymes in Plants Proteolytic Enzymes in Plants (II) ..... Wigglesworth, Miss G. — The Cotyledons of Ginkgo biloba and Cycas revoluta. With a Figure in the Text Willis, J. C., and Burkill, I. H. — Flowers and Insects in Great Britain. Part II. Observations on the Natural Orders Dipsaceae, Plum- baginaceae, Compositae, Umbelliferae, and Cornaceae, made in the Clova Mountains Flowers and Insects in Great Britain. Part III. Observations on the most Specialized Flowers of the Clova Mountains ........ 4 J 3 446 373 35i 45i 625 617 107 1 761 159 79 3 493 435 779 237 597 789 313 539 b X Index. a. Plates. I-VII. VIII-X. XI. XII, XIII. XIV, XV. XVI, XVII. XVIII. XIX. XX. XXI-XXIII. XXIV. XXV, XXVI. XXVII, XXVIII. XXIX. XXX-XXXII. XXXIII-XXXV. XXXVI. XXXVII-XXXIX. XL. B. LIST OF ILLUSTRATIONS. Origin of Monocotyledons (Sargant). Streptopogon (Salmon). Cuphea (Sprague). Monascus (Barker). Pollen-Mother-Cells of Larix (Allen). Picea excelsa (Miyake). Diseases of the Sugar-Cane in the West Indies (Howard). Roots of Dioscorea prehensilis (Hill and Freeman). Medullosa anglica (Arber). Kalanchoe Hybrid (Thiselton-Dyer). Old Gymnospermous Seeds (Oliver). Structure of Schizaea malaccana, Baker (Tansley and Chick). Gymnoascaceae (Dale). Resticularia (Fritsch). Araceae (Campbell). Solenostelic Ferns (Gwynne-Vaughan). Corynocarpus (Hemsley). Sparmannia africana (R. Scott). Proliferous Pinus Cone (Thiselton-Dyer). b . Figures. i-io. Origin of Monocotyledons (Sargant). 11-14. Artificial production of Rhythm in Plants (Darwin and Pertz). 15. Observations on the Biology of Roridula (Marloth). 16. The Dispersal of Mangrove Seedlings (Crossland). 17. Explosive Discharge of Antherozoids in Fegatella conica (Cavers). 18. Abnormal plurality of Sporangia in Lycopodium rigidum (Bower). 19. Roots of Dioscorea prehensilis (Hill and Freeman). 20. Transverse section of Lagenostoma (Oliver). 21, 22. Origin of the Archegonium (Davis). 23. Structure of Schizaea Malaccana (Tansley and Chick). 24, 25. Schizaea dichotoma (Boodle). 26. Schizaea pusilla (Boodle). 27, 28. Corynocarpus (Hemsley). 29. The Cotyledons of Ginkgo and Cycas (Wigglesworth). 30-32. The 1 Epidermoidal ’ layer of Calamite Roots (Stopes). A Theory of the Origin of Monocotyledons, founded on the Structure of their Seedlings. BY ETHEL SARGANT. With Plates I- VII and ten Figures in the Text. HEN some years ago I was working out the anatomical V V structure of the seedlings of Arum maculatum in collaboration with Mrs. Scott (36), we examined the seedlings of some other Aroids, and compared them with two species of Lilium seedlings. The anatomy of seedling Monocotyle- dons has received but little attention from botanists, and Dr. D. H. Scott suggested that I should pursue the subject by making a comparative study of those already collected by him from the material at Kew, and preserved for future investigation. I have to thank him not only for the start then made, but for his unfailing interest in the work as it developed, and for constant help in obtaining fresh supplies of material. The object proposed from the first was to throw light, if possible, on the relationship between Monocotyledons and Dicotyledons. After some months of work in my own laboratory on the Kew material, I found it desirable to modify and extend the original scheme. The vascular system of the cotyledon, hypocotyl, and primary root appeared in the specimens I examined to be characteristic of the species. One of my [Annals of Botany, Vol. XVII. No. LXV. January, 1903. J 2 Sargant . — Theory of the Origin of Monocotyledons early observations- the comparison of a seedling Anthurium with seedlings of Arum and LUium — had suggested that this symmetry might furnish a new systematic character of some importance. The systematic value of any unproven character can be determined only by the careful comparative study of allied forms, and I therefore determined to confine my observations to a single family, and to work that out as fully as possible. With this object I began a careful study of seedlings belonging to the order Liliaceae. The collection of material with all the help which Kew could give, and aided by the kindness of botanists in many countries, has been a laborious task. Seedlings have been raised from seed collected in my own garden, where I have cultivated a large collection of Liliaceous plants. I have also received seed from many sources, and I wish here to thank the Director of Kew Gardens and his Staff for their kindness in furnishing me with seedlings and seeds, and in naming the specimens which I have myself cultivated. My thanks are also due to those botanists who have sent me seeds, and in particular to Mr. Thomas Hanbury, of La Mortola, Professor S. Ikeno, of Tokyo, Mr. W. R. Guilfoyle, of Melbourne, Dr. J. H. Wilson, of St. Andrews, Mr. J. H. Maiden, of Sydney, Dr. K, Reiche, in Chili, Professor D. H. Campbell, and my neighbour, Mr. A. J. Crosfield. I have succeeded in preserving seedlings belonging to 125 species from sixty genera within the Liliaceae, and over sixty species of other Monocotyledons. The collection of Liliaceous seed- lings is fairly representative of northern genera : it is weak in species from the southern hemisphere, and I am particularly in want of more forms endemic to Australia and Chili. The examination of this material is very far from complete. I have thoroughly worked out and made notes on some sixty species from the Liliaceae, and I have sections from about twenty-five species belonging to other monocotyledonous families. During a great part of the time employed in preparing sections and indexing them, as well as in drawing and registering the material, I have been admirably assisted founded on the Structure of their Seedlings. 3 by Miss E. N. Thomas. Most of the figures illustrating this paper have been drawn by Miss Agnes Robertson, who has also assisted me in many ways during the preparation of it. Nature of the Evidence. The examination of forms within the Liliaceae has con- vinced me that some vascular characters of the young seed- ling have real systematic value. At an age when the plant consists of cotyledon, hypocotyl, and primary root, with an embryonic plumule sheltered by the base of the cotyledon, the vascular system — in species which at that age have differen- tiated one — does often indicate the relationship of allied genera to each other. The genera Anemarrhena^ Asphodelus, and Asphodeline , for example, are placed together by all systematists, and the vascular structure of their seedlings shows an identical ground- plan, though there are considerable modifications of the type in the two latter genera. So far the embryological evi- dence simply confirms the conclusions already drawn from the study of the mature characters. But when the unmistak- able Anemarrhena type of symmetry is discovered in the seedlings of Galtonia and Albuca, we have an unexpected link between two groups of genera widely separated by sys- tematists. The instance just quoted is of exceptional interest for reasons already suggested in a preliminary notice, which appeared in the May number of the 4 New Phytologist 5 (35). But it is only a fragment from a considerable body of evidence, which leads to the conclusion that embryological characters of the kind described can be shown to throw light on the inter-relationship of genera within the Liliaceae and allied orders. Until the monograph I am preparing on the comparative anatomy of seedlings within the Liliaceae is completed, this evidence will not be published in detail. But I hope to give a sufficiently full sketch of it here to justify the publication 4 Sargant. — Theory of the Origin of Monocotyledons of a theory on the origin of Monocotyledons, founded primarily on the structure of their seedlings, and supported by the com- parison of this structure with that of some Ranunculaceous genera in which the cotyledons are more or less completely united. The argument requires that some weight should be given to the vascular system of the seedling as affording indications of its race-history. This postulate stated, I will briefly sketch the theory I have formed, and indicate the nature of the evidence on which it rests, before proceeding to give the evidence itself in greater detail than was possible in a pre- liminary notice. The study of Liliaceous seedlings has led me to the con- clusion that the various types of vascular symmetry found within the order can be linked with the type found in Anemarrhena , Albuca , and Galtonia , through more than one series of intermediate forms. I regard the Anemarrhena type as primitive, and as the starting-point from which most, if not all, the vascular types characteristic of Liliaceous seedlings have been historically derived. The cotyledon of Anemarrhena contains two massive bun- dles which together form a tetrarch stele in the primary root. This structure originally suggested to me the possibility of a fusion of two seed-leaves in some remote ancestor to form the single cotyledon of Anemarrhena. According to this view each bundle in the hypocotyl represents the trace of one seed-leaf. The seedlings of certain Dicotyledons possess seed-leaves which are partially united, sometimes by one margin only, but more often by both. In the latter case the united petioles form a tube, which is sometimes of considerable length. Petiolar tubes of this kind are found in several species of Anemone and Delphinium ; in two species at least of Ranunculus and one of Trollius ; in Aconitum Author a and Eranthis hiemalis. The authorities for these statements will be found in Part II. Many other genera among the Ranunculaceae have cotyle- dons which are concrescent at the base. The petiolar tube founded on the Structure of their Seedlings. 5 of Podophyllum from the allied order Berberidaceae is very well developed. Petiolar tubes are not confined to the Ranunculaceae and their near allies : they are found among the Oxalideae, Cucurbitaceae, Umbelliferae, Primulaceae, Polygonaceae, and probably careful search would discover them among seedlings of other families. In every case investigated they are accompanied by a thickened or at least much shortened hypocotyl. The anatomical structure of the petiolar tube and thickened hypocotyl of Eranthis , as described by M. Sterckx ( 38 , p. 57), early attracted my attention because it recalled that of Anemarrhena. I have therefore studied it in detail. The long petioles of Eranthis cotyledons are united into a narrow cylinder, which is hollow for the greater part of its length. The blades are distinct (PI. VI, Fig. 1). Through- out the length of this tube the blade of each cotyledon is represented by a single massive trace. These traces are con- tinued downwards through the tuberous hypocotyl into the primary root. The behaviour of the cotyledonary traces in the upper part of the tuber is precisely that of the coty- ledonary traces in Anemarrhena where they enter the tran- sitional region. This resemblance is maintained throughout the transition, until — near the base of the tuber — the four phloem groups of Eranthis unite in pairs to form two groups, instead of remaining distinct. The four protoxylem groups, however, can be observed for some time after the xylem plate is formed (PI. VII, Figs. 1 and 3) : in the end the two which are opposite the phloem groups disappear, leaving a diarch root-stele (PI. VII, Fig. 2). The anatomical resemblance between the seedlings of Eranthis and those of Anemarrhena cannot be mistaken when the features just described are represented in diagrams. Its theoretical importance, however, has been denied by Mr. Tansley ( 40 ), Three views are possible. The resemblance may be con- sidered as accidental : as the result of inheritance from a 6 Sargant . — Theory of the Origin of Monocotyledons common ancestor : or as the response of two unrelated forms to similar conditions. The formation of a tetrarch root-stele from two cotyle- donary traces is not common among Monocotyledons. It is, I believe, unknown among Dicotyledons. The indications of such a tetrarch formation in Eranthis are to my mind very clear — I cannot dismiss them as accidental. This considera- tion leads me to believe in a real genetic connexion between Eranthis and Anemarrhena : that they are descended from a common ancestor with two distinct seed-leaves, each repre- sented by a single trace in the hypocotyl. If we suppose that this is in its turn descended from a form in which two traces enter the hypocotyl from each cotyledon, the tetrarch root will no longer present any difficulty. But even if there be no historical connexion between these genera, the structure of Eranthis may nevertheless illustrate the double origin of the Anemarrhena cotyledon. For with- out the analogy of Eranthis the assumption that each trace in the cotyledon of Anemarrhena represented a distinct seed- leaf was groundless. Not only was direct evidence of such a double origin absent, but there was nothing to show that the union of two cotyledons, if it did take place, would actually give rise to such a type of vascular symmetry. To settle the matter by experiment was out of the question. But in Eranthis the cotyledons are partially united, and the vascular symmetry bears a very close resemblance to that of Anemar- rhena. If there is no common stock from which both forms are derived, Eranthis may be considered as a genus in which Nature has partly repeated the experiment which she con- cluded in Anemarrhena , and with a similar result as regards the vascular system. This is the line of argument on which my theory is based, and it remains now to give a fairly full abstract of the evidence which supports it. I propose to do so under two heads. In the first place I shall describe the chief types of vascular symmetry which have so far been found within the Liliaceae, founded on the Structure of their Seedlings. 7 and the intermediate forms which have led me to derive them from the Anemarrhena type. These facts will, I hope, go far to justify the preliminary assumption that the vascular symmetry of the seedling affords a new systematic character, which — at least among the Liliaceae — is often of value in indicating the historical connexion between genera. While on this subject I shall also describe more briefly some monocotyledonous seedlings outside the Liliaceae, and in particular those whose structure connects the group to which they belong with that family. In the second place, I intend to describe in detail the first- year seedling of Eranthis hiemalis , comparing its vascular structure with that of Nigella damascena , already well known through the descriptions of MM. Gerard, Dangeard, and Sterckx. From the other Ranunculaceous species which possess cotyledonary tubes, I have examined and shall shortly describe Anemone coronaria and a species of Delphinium , and for comparison with these exceptional forms I have chosen four species with distinct cotyledons from the same family. In conclusion, the seedling of Ranuncidus Ficaria will be fully described as a type in which the cotyledons are partly united by one margin only. These two chapters will complete the account of the evidence on which my theory is based. This evidence is obviously incomplete. The theory itself cannot be considered as proved in any sense. It is brought forward as a working hypothesis which I have found in practice to be suggestive and illuminating. But a theory of the origin of the mono- cotyledonous cotyledon is in fact a theory of the origin of Monocotyledons themselves, and therefore to the two chapters which contain my own observations on the comparative anatomy of seedlings I shall add a third dealing with the theoretical aspect of the subject. In this I shall try to show that the same habit of life which leads to the partial union of some dicotyledonous seed-leaves may in the past have pro- duced one or more distinct races with seed-leaves so completely united that they appear to form a single member. 8 Sargant . — Theory of the Origin of Monocotyledons Whether the Monocotyledons as we know them now are descended from one such race, or have branched off in this way at several distinct periods and from different dicotyle- donous stocks, must remain an open question for the present. OBSERVATIONS ON THE ANATOMY OF SEEDLINGS. Part I. Monocotyledons. A. Liliaceae. The species cut and completely examined from this family amount to sixty, representing thirty-five genera. Of these, forty-five species, representing twenty-six genera, belong to the four central tribes : Asphodeleae, Allieae, Scilleae, Tulipeae. Three complete series of sections from the transitional regions of three seedlings, differing somewhat in age, have been examined and kept for reference before the final notes on any species were compiled. Where the first seedlings cut have shown considerable diversity of structure, more speci- mens have been examined : in some cases details of seven, eight, or nine seedlings are included in the notes. The series of sections have always been followed from the cotyledon downwards through the hypocotyl into the primary root. This I have found in practice more convenient than working upwards from root to stem. But the lignification of the traces is usually at its maximum about the middle of the transitional region, and in general proceeds upwards and downwards from that level. Many observers have remarked that the limits of the hypocotyl differ according as they are defined by external or internal characters. In this paper I am concerned chiefly with the internal anatomy of the seedling, and I therefore define the upper limit of the hypocotyl by the insertion of the plumular traces on those of the cotyledon, and its lower limit by the formation of a stele with complete root- characters. founded on the Structure of their Seedlings . 9 This region is commonly very short in Monocotyledons. In bulbous or tuberous species it rarely exceeds *5 mm., and in many cases can hardly be said to exist except by a sort of legal fiction. Even in herbaceous and arborescent species the hypocotyl as defined above rarely attains a length of 3 mm. The symmetry of the root-stele is sometimes determined by the cotyledonary traces only : sometimes by cotyledonary and plumular traces together : and in a few exceptional cases it appears to depend on the plumular traces only ( Aloineae , Bulbine , Tamus ). The systematic indications are most con- stant in the first case : that is, when the cotyledonary traces only are continued into the primary root, and its symmetry is unaffected by the insertion of the plumular traces. I have learnt to look on this as the primitive arrangement. It is found in species which are somewhat tardy in developing the plumular leaves. The root-stele in such species is fully differentiated, while the plumular traces are still embryonic. The early or late development of the plumule is of course a question chiefly of the habit of the species, and this is deter- mined by the external conditions to which it is exposed. The seedlings of climbers and arborescent species, for example, commonly develop the plumule early, and the primary root of such species is comparatively long-lived. It must therefore be polyarch in order to attain sufficient girth, and as a rule in plants of this habit many plumular traces are continued down- wards into the root-stele, side by side with the cotyledonary traces. In such cases I have found the features of the transition to vary considerably, even among individuals of the same species. The primitive characters are swamped among those which are more or less dependent on external conditions, and these are necessarily variable. 1. Tribe Scilleae. Seventeen species, representing ten genera, have been examined from this tribe. Albuca Nelsoni. The seedling is slender, and attains some io Sargant . — Theory of the Origin of Monocotyledons size before the position of the plumule is defined externally as a swelling near the base of the cotyledon (A 5 in PL I, Fig. i). The cylindrical cotyledon is green, and acts as the first assimilating organ. Its apex carries the seed out of the ground, and remains within it until the supply of food in the endosperm is exhausted. The primary root is still unbranched in A 5 , and no other has appeared. The upper limit of the root is defined externally by a sudden increase in diameter. Later on, when the base of the cotyledon has expanded into a sheath which envelops the growing plumule (B x in Fig. i, PI. I), this abrupt increase in girth is not so clear, but there is a distinct constriction separating the base of the bulb from the top of the root. The two seedlings figured (A 5 and Bj) have been dissected. In each there are two massive bundles running the whole length of the cotyledon. Their phloem groups are very well developed, as is generally the case when the cotyledon serves as a sucking organ for some time after germination. The cotyledonary sheath of A 5 possesses in addition five lateral bundles, which are formed near the top of the sheath by the branching of the two main bundles. Near the base of the sheath they join the plumular traces above the level at which these are inserted on the main cotyledonary traces. The far larger sheath of the older seedling B x possesses no less than twelve of these minor bundles : all given off by branching from the main bundles, and all ultimately merged in the plumular stele, or ending blindly before the transition from root to stem begins. The presence of lateral bundles in the cotyledonary sheath, though not confined to the Scilleae, is very characteristic of the tribe. They do not always arise by the branching of others, but are sometimes formed independently, and dis- appear without joining other traces. When this is the case they probably serve merely to stiffen the sheath. The seedling A 3 , from which the sections drawn in Figs. 2-4 were cut, is younger than A 5 , and there are only two slender lateral strands in the cotyledonary sheath in addition to the founded on the Structure of their Seedlings. 1 1 two massive bundles on which the transition depends (Fig. 2). These behave precisely as the corresponding bundles of Anemarrhena (Diagram VI). The phloem group of each divides into two parts, and the protoxylem group branches in three directions (px 1 ,px 2 ,px z on one side, and px^px\,px 3 on the other in Fig. 3, PI. I). The four phloem groups thus formed continue downwards into the primary root, but the six protoxylem groups of Fig. 3 are reduced to four by the fusion of px 2 with px' 2 and px z with px\. So far the transition follows the Anemarrhena type exactly. But in Albuca the permanent stele of the primary root is not always tetrarch. The protoxylem group px z + px\ in Fig. 4 is less prominent than the other three. A little lower down it has disappeared altogether ; the phloem groups on either side of it have united, and the root-stele is triarch. In the seed- ling A 5 a similar suppression occurs. The primitive tetrarch structure is barely indicated before two of the protoxylem groups — those corresponding to px 2 4- px' 2 and px. A + px\ in Fig. 3 — become less prominent, and for a considerable distance it appears as if the root would ultimately become diarch. In the end, however, one of the menaced protoxylem groups recovers itself, and the root is triarch as in A 3 . In both seedlings the lateral protoxylem group which persists is that on the side from which the plumular traces have entered the stele. If the irregularity just described could be thought to cast any doubt on the homology of the transition in Albuca with that of Anemarrhena , that doubt would be removed by the series from B 1} the oldest seedling cut. In this transition the two cotyledonary traces give rise to a tetrarch root. The process is the same as in Anemarrhena , step for step, and when once formed the root continues tetrarch to the end of the series, a distance of *75 mm. from its first formation. The vascular structure of the seedling in Albuca Nelsoni is doubly interesting. In the first place it follows the Anemar- rhena type of transition so closely as to demonstrate the existence of this type within the Scilleae. In the second, 12 Sargant . — Theory of the Origin of Monocotyledons its variations from the Anemarrhena structure are hardly less important. The existence of lateral bundles in the cotyledonary sheath is, as I have said, characteristic of this tribe. In Albuca we see a number of such lateral bundles present side by side with the main bundles, but obviously derived from them, and exercising no influence on the symmetry of the hypocotyle- donary stele. In other genera such lateral bundles assume a greater importance, and to some extent replace the main bundles, but these variants on the typical structure are linked to Albuca by a series of intermediate forms, some of which I shall describe in detail (. Hyacinthus romanus , Muscari atlan- ticum , M. armenaicum). The comparative study of these species and others, joined with that of a series among the Asphodeleae, leaves no doubt that the lateral bundles of the cotyledon are structures of more recent date than the main bundles. Again, the formation of a triarch root in some individuals of this species by the suppression of the median protoxylem group in one of the main bundles (A 3 , A 5 ), and the temporary suppression of the corresponding group in A 5 , indicates a tendency in these median protoxylem groups to disappear. Moreover, the fact that the median group which survives is that next to the plumular traces shows the influence that these — when developed early — may exercise on the symmetry of the stele. Galtonia candicans and Dipcadi serotinum are alike in possessing several lateral bundles in the cotyledonary sheath besides the two main bundles which run the whole length of the cotyledon. In both genera two or more of these lateral bundles, together with the plumular traces inserted on them, enter the hypocotyledonary stele, and exercise a capricious influence on the symmetry of the root- stele. Individuals within the same species differ profoundly from each other in the details of transition : triarch, tetrarch, or pentarch steles are found in the primary root of Galtonia candicans ; triarch or tetrarch steles in that of Dipcadi serotinum . The behaviour founded on the Structure of their Seedlings . 13 of the two main bundles themselves is affected by these irregularities, but in some specimens of both species they follow the Anemarrhena type exactly, and in almost all they clearly begin on that plan, though it is not pursued throughout the transition. Species in which the transition presents such irregularities cannot be fully described here : they are mentioned because in individuals of both species a modification of the Anemar- rhena transition is found which reappears elsewhere. In this variant the phloem of each main bundle divides into three groups, of which the median one remains in situ A B C and is continued downwards unchanged. The right-hand branch unites with the adjacent branch from the other bundle, and a similar fusion occurs on the opposite side of the stele. The protoxylem of each main bundle divides into two groups, each of which becomes external as it takes up its position on one side or other of the median phloem group. The root is of course tetrarch (Diagram I). The examination of the transitional region in six seedlings of Galtonia candicans has convinced me that the type of transition just described is derived from type 4 [Anemarrhena). It stands in precisely the same relation to that type as Van Tieghem’s type 3 to his type i 1 , and for convenience I shall refer to it as type 5. The genera Hyacinthus and Muscari include a number 1 Traite de Botanique, ed. ii, 1891, vol. i, p. 782. 14 Sargant . — Theory of the Origin of Monocotyledons of forms in which the lateral bundles of the cotyledon take a perfectly regular share in the formation of the root-stele. The species Hyacinthus romanus , Muscari atlanticum , M. armenaicum and M. neglectum , for example, form a series in which the lateral traces become more and more important until they supply a full half of the root-stele. Hyacinthus romanus. In the seedling figured (A 5 , PI. I, Fig. 5) there are four slender lateral strands in the cotyle- donary sheath at an age when even the midrib is not indicated in the first leaf (PI. I, Fig. 6). These four strands unite in pairs : the two traces thus formed enter the stele just above the transitional region, and take some slight share in the process of transition from stem to root. The two main bundles divide exactly as in Albuca. The bifurcation of the phloem groups is somewhat masked by the early formation of a phloem girdle, but in very young seed- lings this is still incomplete, and there is no difficulty — when the series of sections from seedling A 5 is followed with care — in identifying the phloem group to the top or north of the section figured in PI. I, Fig. 7 with half the phloem of M 2 . The rest has united with the adjacent phloem group of the lateral bundle 1 2 to form the right-hand or eastern group. The whole of the phloem belonging to has joined that of lj, and the united groups are now represented by the phloem crescent on the left hand or south-western side of the stele (Pl. I, Fig. 7). The xylem is in two masses, between which extends a slender crescent of protoxylem elements. This is formed by the xylem of the two lateral bundles l x and 1 2 , together with protoxylem elements from the two main bundles M 1 and M 2 . These will together form the protoxylem group px 3 + px' 3 of figures 8 and 9 on the same plate. The corresponding group to the north of the stele in Fig. 8 is formed by the union of protoxylem branches from the two xylem masses shown in Fig. 7 (PI. I, Fig. 8, px 2 + p%' p. 25) ; not as in Chlorogalmn by the survival of two which were at first sup- pressed. Bravoa gemmiflora. The cotyledon remains within the seed as a sucking organ. It contains four bundles in the sheath, all quite distinct from each other. Two, distinguished from the others by their size and position, represent the main bundles. These two approach each other in the transitional region without uniting. The plumular traces insert themselves on those from the cotyledon, and the root-stele is triarch. Its formation seems to be governed by cotyledonary traces only. Agave spicata. The whole seedling is succulent. The cotyledon, after sucking out the food from the endosperm, emerges from the ground as a green fleshy spike of triangular section, carrying the seed-coats on its apex. It contains four bundles, of which two, from their size and position, can be identified as the main bundles. There is a comparatively long hypocotyl in these seedlings, with a stele 4 2 Sargant. — T heory of the Origin of Monocotyledons containing three or four traces from the cotyledon, and these retain their stem-structure for some distance downwards. In one seedling I found six traces, for two entered it from the plumule, but this is exceptional. As a rule, a portion of each plumular trace is inserted on the ring of cotyledonary traces at the first node, without altering the symmetry of the transition, but the rest of the plumular stele is continued directly downwards, and becomes the stele of the first cauline root. The structure of cotyledon and hypocotyl in A. Rovelliana seems essentially the same as that of A. spicata . Doryanthes Palmeri The seedling is very stout and fleshy. The first leaf is rolled upon itself, and forms a trumpet-shaped cylinder which is in a straight line with the hypocotyl and primary root. The cotyledon projects horizontally from the axis. Its blade is a flat, thick disc, covered for some time by the brown seed-coats. It is attached to a very short petiole which clasps the axis with its massive sheath. There are four main veins in the cotyledon, and they all enter the axis through the petiole. The plumular bundles form a ring of eight traces, which are joined at the node by the four traces from the cotyledon. These enter the stele in pairs, each pair displacing one of the plumular traces. The stele of the hypocotyl now contains ten distinct bundles. Within this circle are the two plumular traces displaced by the entrance of the cotyledonary traces. The displaced traces are not adjacent to each other, but separated by two others in the original circle of eight, and with these two they now unite. The hypocotyl in this species is comparatively long, 3 mm., even in quite young seedlings. The transition from a ring of ten stem-bundles to a 10-arch root-stele takes place gradually by branching and rotation of the xylem groups only — Van Tieghem’s type 1. The seedling of D. excelsa resembles that of D. Palmeri both in its external characters and its vascular symmetry. founded on the S true hire of their Seedlings. 43 For some time I was tempted to look on Doryanthes as a genus in which the seedling possessed characters more primitive in some respects than those of Anemarrhena. The two pairs of bundles, though distinct throughout, might be identified with the two massive bundles in the cotyledon of Anejnarrhena , each of which behaves like a double bundle during the process of transition. The fact that the two pairs of cotyledonary traces enter the plumular stele at two distinct points suggested at first their origin from distinct members, but the arrangement may be merely adaptive to secure greater mechanical stability at the insertion of the cotyledon. Until the seedlings of allied forms have been examined there can be no further comparative evidence concerning the origin of the peculiar vascular structure of Doryanthes. The seedlings of Agave and Bravoa — two genera nearly related to Doryanthes by their mature characters — are, as we have seen, designed on a Liliaceous model. I am inclined to believe the vascular symmetry of the Doryanthes seedling to be derived from that of some form resembling Agave. There are two reasons against supposing it primitive. In the first place the seedling of Doryanthes is, both anatomically and in external form, of the shrubby or arbo- rescent type, which is, as a rule, much modified in response to its environment. In the second, the floral structure of Amaryllids is clearly derived from the Liliaceous type, and we are therefore less likely to find a primitive form among them than within the Liliaceae. Iridaceae. Four species representing two genera have been examined from this family. The three species of Iris, I. sibirica , I. Boissieri , and an unnamed species from China, agree in possessing a single massive bundle which runs the whole length of the cotyledon, and opens out into a double bundle of characteristic form near the base of the sheath. Plumular traces take part in the transition to a root-structure, and the root is tetrarch ( Iris sp. 44 Sargant. — T heory of the Origin of Monocotyledons and I. sibiricd) or triarch (I. Boissieri). The root of Iris sp . appears diarch when first formed, but very soon becomes tetrarch, and the whole process of transition, so far as it could be followed in the rather old seedlings, recalled that of Chlorogalum (p. 29). Freesia sp. (garden variety). The cotyledon contains three bundles in its lower part or sheath, and the central one appears double just above the first node. One plumular trace at least takes part in the transition. The root is tetrarch. Aroideae. Three species representing three genera have been examined from this family ; Arum maculatum very thoroughly, the others in less detail. The structure — internal and external — of the Arum macu- latum seedling has been described elsewhere (36). The seed ripened in the summer may germinate before winter, or remain dormant until the spring. In either case no part of it appears above ground until the second spring after the seed has been sown. The apex of the cotyledon remains within the seed as a sucking organ, while the lower part is transformed into a cylinder which sheathes the young stem-bud and is terminated by the hypocotyl. This begins to be thickened in the early stages of germination, and it swells into a tuber as the stores of food are transferred to it from the endosperm through the bundles which run down the cotyledonary tube. By the end of the summer following the sowing of the seed, the whole cotyledon, having emptied the seed of its food-supplies, is detached from the tuber. The stem-bud is exposed by the removal of the tube which has hitherto surrounded it, and in the following spring the first green leaf pushes through the soil. The vascular system of the cotyledon has been profoundly modified by its peculiar habit. Of its five bundles the central one is larger than the others, but it never appears double. The plumular traces are inserted at the first node on those founded on the Structure of their Seedlings. 45 from the cotyledon. They rarely affect the symmetry of the root-stele, which is commonly triarch. It depends on the central trace from the cotyledon, and a lateral trace on either side of it. Each of these lateral traces is formed by the fusion of a pair of lateral bundles. The transition takes place according to Van Tieghem’s type 3. The xylem groups are continued straight downwards, the protoxylem becoming external on the way, and each phloem group divides, the right-hand segment of one uniting with the left-hand segment of the next. Nothing in the vascular symmetry of Arum suggests a relationship with any Liliaceous type. All that can be said is that the possibility of such relationship is not excluded. The seedling of Arum maculatum is hardly more unlike that of Anemarrhena in its vascular structure than is that of Veratrum , for instance. The seedling of Arisaema speciosum resembles that of Arum in many points. The tuber is already formed very shortly after germination, and the first green leaf makes its way out of the cotyledonary sheath early in the first season of growth. The cotyledon contains seven or nine bundles, and the primary root is either triarch or tetrarch. Anthurium Baker ianum differs completely from the genera just described both in the external form and in the internal structure of its seedling. The cotyledon remains underground — its apex enclosed within the endosperm of the seed. The petiole of the cotyledon is short, and its base is expanded into an open sheath which shelters the plumule without en- closing it. The first leaf develops early. It breaks through the soil and becomes green, while its base sheathes the younger leaves and the growing point. They are thus safely packed between the cotyledon and the first leaf. Sections through the apex of the cotyledon as it lies within the endosperm show two bundles within it. They unite before passing into the petiole, and the bundle which enters the sheath of the cotyledon is apparently single. During the transition, however, it opens out into a double bundle. 46 Sargant . — Theory of the Origin of Monocotyledons A single trace from the plumule approaches the double cotyledonary trace, and with it forms a diarch root-stele. The transition from stem to root takes place precisely as in Zygadenus (PI. V, Figs. 9-12). These facts certainly suggest that Anthurium is a form intermediate between the typical Liliaceous type and that of Arum and Arisaema , and this is the position assigned to it by systematic botanists on the evidence of its floral structure. If the relationship between Arum and the primitive Lily- type be admitted, we have still to decide which of the two is the older. Does the line of descent start from the mother- form of the Lily family and end in such genera as Arum and Arisaema , or do these represent a type earlier than that of the Lilies ? The succession suggested by the structure of their seedlings is from Anemarrhena , through forms perhaps resembling Chlorogalum and Arthropodium , to others like Allium and Zygadenus ; thence to Anthurium. We may hope that future research will fill up the gap between Anthurium and Arum. Should it do so, would it be possible to read the chain backwards with equal probability ? If we make the attempt, we must suppose the point at which Anthurium approaches the Liliaceae to be that of greatest antiquity. A form resembling Zygadenus in the structure of its seedling must be accepted as the primitive type of that family. But the comparative study of seedling forms within the Liliaceae has shown that types of vascular symmetry differing so widely from each other as those of Eremurus , Zygadenus , and Eucomis can all be referred to a single scheme — that which I have called type 4 (Diagram VI, p. 26). It is incredible that these genera should possess three distinct types of vascular structure in their seedlings, each of which should be modified through three distinct lines of descent until they all reached the same well-marked form — a form, moreover, which then appears in two genera such as Anemarrhena and Albuca , which have been always placed in separate tribes owing to the difference in their mature characters. founded on the Structure of their Seedlings . 47 These considerations lead to the conclusion that Anthurium must be held a more primitive type than Arum or Arisaema. Palmae. A number of young Palm seedlings were included in the Kew collection, and of these I have examined nine species. In three of them my observations are very incomplete, owing partly to a want of material at the proper age, and partly to difficulties of manipulation. The vascular structure of young Palms has often to be worked out by hand sections only, as the woody tissues of the axis do not embed well in paraffin. Good microtome series have, however, been cut through the hypocotyls of Desmoncus minor, Thrinax excetsa, Areca sapida , and Phoenix dactylifera , and hand sections have given goods results in two other species, Desmoncus sp. and Acantho- phoenix crinita. I can give a fairly complete account of the vascular system in the seedlings of these six species, though even here the details are commonly obscured by the massive development of the plumular traces due to the comparatively advanced age of the seedlings. The external characters of all the Palm seedlings I have seen are much modified from the ordinary monocotylecjonous type by the arborescent habit of the family, and their internal structure is not less profoundly affected. The first leaves are developed early. Their tissues are hard and woody from the first, owing to the number of vascular bundles developed within them and the stiffening of those bundles by massive sclerenchymatous sheaths. The primary root is always pretty well developed, and is sometimes the main root for a long time {Thrinax excetsa, Chamaerops humitis). In other species it is soon surpassed in length and thickness by the first cauline root. The vascular system of the latter is commonly the direct prolongation of plumular traces, as that of the primary root is of cotyledonary traces. The tip of the cotyledon is merely a sucking organ, which for many months after germination continues to supply the seedling with nourishment from the stores laid up in the 48 Sargctnt. — Theory of the Origin of Monocotyledons endosperm. The lower part of the cotyledon plays many parts, and is modified in shape and texture to suit the habit of the seedling. In Thrinax excelsa the plumular axis is connected with the seed by the long and rather slender petiole of the cotyledon. This expands at the base into a tough membranous sheath which completely surrounds the axis at its insertion. The four cotyledonary bundles run downwards through the sheath, in the same direction as the plumular traces, but outside them. Just above the node these four bundles form the outermost of a series of concentric circles in which all the traces of the axis are arranged, and they are equidistant from each other. At the first node the traces from the cotyledon run inwards — from the four points of the compass, as it were. Four plumular traces alternate with them in the stele of the hypocotyl, and the remainder are inserted on one or other of the circle of eight traces. An octarch root-stele follows quite regularly, apparently according to Van Tieghem’s type i, by branching of the xylem groups. In Desmoncus sp ., D. minor , Areca sapid a, and Acantho- phoenix crinita , the cotyledon has a short petiole and a thick fleshy^sheath which is continuous with the primary root. The plumule is inclined to the cotyledon — sometimes almost at a right angle— and its traces are commonly continued down- wards into one or more cauline roots, which penetrate the fleshy tissue of the cotyledonary sheath. The apex of the cotyledon in the four species we are considering contains from ten to twelve bundles, irregularly disposed in a circle and without any trace of a midrib. Near the base of the petiole these become reduced to four by fusion with each other. In the sheath they approach each other in pairs, and when the plumular traces appear in the section the cotyledonary traces have united to form two massive bundles facing each other. Sections which cut the cotyledonary traces transversely must of course pass through the plumular traces obliquely, and this distinction enables us to follow the course of the founded on the Structure of their Seedlings. 49 cotyledonary traces into the root-stele. They are always accompanied by two or three plumular traces, and they enter the stele from opposite sides. Thus the two groups of cotyledonary elements in the xylem of the root-stele are separated from each other by two or more groups of plumular elements. The root is often tetrarch or pentarch : sometimes hexarch or heptarch. The details of transition are never quite clear, but the process follows Van Tieghem’s type 1. In Desmoncus sp. the root, which is tetrarch when first formed, becomes octarch lower down. The habit of the seedling of Phoenix dactylifera is very distinct from that of any of the Palm seedlings just de- scribed. The bundles of the inflated cotyledonary sheath form a circle of about ten, which are all continued into the primary root. The plumular traces are of course internal to this circle from the beginning. They are inserted on the cotyledonary traces without affecting the symmetry of the primary root-stele. The transition to a root-structure takes place by the branching of the xylem (Van Tieghem’s type 1), and the root is commonly 10-arch. The absence of a midrib in the cotyledon of the Palms is conspicuous not only in all the seedlings described, but also in two others which I have partly examined, Geonoma oxycarpa and Chamaerops humilis . But it should be added that the foliage leaves do not always possess a midrib, and that when present it is little distinguished from the others. The adaptations to an arborescent habit are so well marked in all the species that the presumption is certainly against the primitive character of any particular feature. I may, however, mention that the well-grown cotyledon of Chamaerops humilis when extracted from the seed is seen to have a bifid apex. I remarked on this in my notes before the theory of a com- pound cotyledon had occurred to me, and compared it to the two lobes of a brain. The cotyledon of Ch. Fortnnei is still more completely bilobed. This may very possibly be an adaptive character, but I should be glad to know whether it occurs generally among large-seeded Palms. E 50 Sargant. — Theory of the Origin of Monocoty ledons On the whole the point to which I attach most importance is the gathering-up of the cotyledonary bundles into two groups which occurs in four out of the six species I have examined with care. Of the three species partially examined Euterpe edulis appears to resemble Thrinax , but the whole process is obscure. The cotyledonary traces have not been followed into the hypocotyl in Geonoma and Chamaevops. Thus in four species out of seven there is a twofold symmetry in the traces of the cotyledon within the transitional region. In two more the symmetry is fourfold. The seventh, Phoenix dactylifera , shows an exceptional vascular symmetry corresponding with the exceptional habit of the whole seedling. Scitamineae. Five species from five different genera of this family have been worked out by Miss Thomas with success. They fall naturally into two groups. The species of Musa and Carina are large and generally fleshy plants. Their seedlings resemble those of arborescent or shrubby genera, and their vascular symmetry corresponds to this habit. A number of massive bundles are found in the cotyledon. They are continued downwards into the hypocotyl, and with the assistance of plumular traces they form a poly- arch root-stele. The seedlings of Amomum , Elettaria , and Renealmia are of a different character, less fleshy, and rather of the herbaceous than the shrubby type. The three species examined in detail are Amomum angustifolium , Elettaria cardamomum , and Renealmia racemosa. Their vascular symmetry is strikingly similar. The apex of the cotyledon remains permanently in the seed. It contains two bundles which there appear equivalent. They run the whole length of the petiole and sheath. But in the upper part of the sheath they are not symmetrically placed with regard to its outline. One occupies the position of a midrib, while the other might be taken for a lateral bundle without a pendant on the other side. This want of founded on the Structure of their Seedlings. 51 symmetry is probably due to mechanical causes. The seed is connected with the main axis by the long slender petiole of the cotyledon, and this enters the rather complicated cotyledonary sheath at an acute angle. The two bundles are so placed as to give strength and elasticity to the junction. In all three species there is a fairly long hypocotyl ; that is, the plumular traces join those from the cotyledon some distance above the level at which the stele becomes completely root-like. The cotyledonary traces are placed opposite each other in the sheath just above the first node, and in this region they seem perfectly equivalent. The traces of the cotyledon enter the hypocotyledonary stele from opposite sides, and are separated by two plumular traces. The other bundles of the plumule are inserted on one or other of these four traces at the first node. The fourfold stele below the first node has a very character- istic appearance. Each of the four xylem* masses is crescent- shaped, and each group of phloem is placed in the concavity of a crescent. As the eight horns of the xylem crescents reach the pericycle and form four pairs of xylem rays alternating with four phloem groups, we seem at first to be looking at a tetrarch root. Closer inspection shows that the centre of the stele is occupied by a single group of protoxylem formed by the union of four internal groups. From this centre radiate four narrow rays of parenchymatous tissue dividing the four xylem crescents from each other. Before the protoxylem becomes external a number of cauline roots are given off from the stele almost simultaneously. There are commonly four of these, and each is placed opposite one of the parenchymatous rays. The primary root is tetrarch in Renealmia racemosa and Elettaria cardamomum. In the only complete series cut from Amonium angustifolium the central stele vanishes after giving off four cauline roots simultaneously. There would seem to be no primary root at all. This may be an individual peculiarity, or the primary root may be present but inclined at such an angle as to be mistaken for a cauline root. E 3 52 Sorgant . — Theory of the Origin of Monocofy/edons There are points in this structure which recall that of Thrinax. The most important feature is. I think, the presence of two equivalent bundles in the cotyledon. The twenty-five species of Monocotyledons — exclusive of the Liliaceae — which have just been described, fall naturally into two groups. The anatomy of seedlings belonging to the Amaryllidaceae, Iridaceae, and Aroideae seems to be derived from a Liliaceous type. That of the Palmae and Scitamineae is distinct in character, but the dual symmetry of the cotyledon is not less marked. The evidence from these two families, so far as it goes, is perfectly consistent with the hypothesis of a double cotyledonary member, and even gives it some support. Part II. Ranunculaceae. No detailed comparative study of this family has been attempted. The seedling which first attracted my attention was that of Eranthis hiemalis as described by M. Sterckx (38), to whose excellent monograph I have referred elsewhere. Since repeating his observations on the vascular system of Eranthis with particular reference to the tuberous hypocotyl, I have examined the seedlings of two other species possessing cotyledonary tubes : Delphinium sp. (possibly D. nudicaule ) and Anemone coronaria , and also two species with distinct epigaeic cotyledons, Delphinium Requienii and Nigella dama - scena. M. Sterckx has shown that the single cotyledonary member of Ranunculus Ficaria is in all probability formed by the union of two cotyledons by one margin only. I have repeated his observations on the external features of this seedling, and have made a careful study of the course of the vascular bundles in the cotyledon, hypocotyl, and primary root. For comparison two other species which show apparent lateral insertion of the cotyledons were chosen, Ranunculus Chius with epigaeic, and Anemone nemorosa with hypogaeic cotyledons. founded on the Structure of their Seedlings. 53 Eight species in all, representing five genera, have been examined, and will now be described in more or less detail. The seedling of Nigella damascena has been chosen as the type of vascular structure in this family by MM. Gerard (13), Dangeard (9), and Sterckx (38). There is nothing to add to their account of the anatomy of the hypocotyl in this species. An outline of it will be sufficient here. The vascular symmetry agrees in all essentials with that of Delphinium Requienii , and Diagram IX represents the transition from a stem to a root structure within the hypocotyl of both species. The three main bundles of the blade enter the petiole of each cotyledon, but soon unite to form a single massive bundle. This is particularly clear in Delphinium Requienii because, owing to the greater length of the petioles in this species, the union of the lateral bundles with the midrib takes place at some distance above the insertion of the cotyledons on the axis. At the level where it is joined by the lateral bundles the midrib is still to all appearance single. Near the base of the petiole, the single massive bundle of each cotyledon opens out into a double structure precisely similar to that formed by each cotyledonary trace in Anemar- rhena (Diagram VI). Both in Nigella and Delphinium however the double character of each bundle is very clear a short distance above the insertion of the cotyledonary traces on the plumular stele. M. Dangeard is so much struck by this feature in the cotyledon of Nigella that he does not hesitate to describe its petiole as containing two bundles (9, p. 85 ). In this interpretation of the structure I entirely agree : the vascular symmetry of this genus and those which resemble it is much simplified by supposing four cotyledonary traces to enter the root-stele. A similar assumption has already been made with regard to the two traces of the cotyledon in Anemarrhena (p. 6 ). The resemblance between the vascular symmetry of Del- phinium or Nigella and that of Anemarrhena is obscured at the first node from a very simple cause. The traces of the 54 Sargant .— Theory of the Origin of Monocotyledons plumular stele are much more numerous and better differen- tiated in the Ranunculaceous seedlings examined than in seedlings of Anemarrhena which have reached the same stage of development. In Anemarrhena the plumule lags far behind the cotyledon. Moreover, among Dicotyledons a cambium is very well developed in the traces of both. Its position is indicated by the waved line in Diagram IX. The stele of the hypocotyl is elliptical in Delphinium and Nigella. The two groups of cotyledonary xylem are placed at the extremities of the major axis, while two of the four phloem masses fuse with each cluster of plumular phloem ABC groups (B, Diagram IX). The root-stele becomes diarch at once. A considerable part of the metaxylem, as well as much of both phloem groups, is derived from plumular traces. These changes take place in the upper part of the elongated hypocotyl, and are commonly complete a few millimetres below the first node. Several species of Delphinium have the petioles of their cotyledons united into a. tube, and I have made a complete examination of one such species, probably D. nudicaide. The first leaves of this species are developed in the summer after germination, and they soon burst out of the sheath formed by the base of the united cotyledons (Lubbock, 30, vol. i. P- 97)- The cylinder formed by the united cotyledons is solid founded on the Structure of their Seedlings. 55 for about two-thirds of its length downwards from the inser- tion of the blades. In the lower part there is a small central cavity, not very clearly defined in transverse section, which gradually opens out as it descends, and so forms the conical chamber enclosing the stem-bud. Two opposite bundles, one from each cotyledon, run the whole length of the cylinder, and each remains single until it reaches the level of the plumular growing-point. Here both begin to open out into a double structure. The activity of the cambium within them is already marked : at this level in a seedling so young that the first leaf is a mere rudiment in which the midrib is just indicated, two rows of radial unligni- fied xylem elements are found in each trace inside the cambial zone. As in following the series of sections from this seedling we approach the first node, two unlignifled plumular traces appear opposite each other between the two traces from the cotyledon. The stele is elliptical as in B, Diagram IX. A well-marked cambium is present in all the traces, and also between them. It forms a complete ellipse enclosing all the xylem. The formation of secondary tissue has already begun within the traces, where we find two or more rows of unligni- fied xylem elements outside the primary xylem which is also as yet unlignified. The formation of secondary tissue reaches its maximum a little lower down, where in this young seedling the primary elements belonging to the plumular traces have almost dis- appeared. The four cotyledonary phloem groups are approaching each other in pairs. They are separated from the well-lignified primary xylem of the cotyledon by a con- siderable bulk of secondary tissue. The secondary formations are best developed in those segments of the ellipse which were occupied by plumular traces : they are thinnest outside the two groups of cotyledonary xylem, in which the protoxylem is already external. The diarch root-stele is formed as in Diagram IX. The activity of the cambium decreases in the lower region of 56 Sargant . — Theory of the Origin of Monocotyledons the hypocotyl, but a true cambial zone is still found in the upper part of the root. The vascular symmetry of this species is practically identical with that figured in Diagram IX as the normal Ranunculace- ous type. The only peculiarity which deserves notice is the precocious development of a cambium, and its extraordinary activity. This suggests that the growth of the hypocotyl into a spindle-shaped tuber, which is well marked at the end of the season, may be due to tissues added by the action of a normal cambium-ring. If so, the mature tuber may resemble that of Corydalis solida (Jost, 28). The seedlings examined of Anemone coronaria are all much older than those of Delphinium sp., whose structure has just been described. The vascular symmetry of their cotyledon, hypocotyl, and primary root is however identical with that of Delphinium sp. Much more secondary tissue is present, and the stele has become circular owing to the greater activity of the cambium opposite the plumular traces. The secondary tissues are continued downwards far below the level at which the stele has become root-like. At no level have I found lignified secondary tissue outside the two protoxylem groups of the central plate of primary xylem, but radial rows of five or six well-lignified elements are found on the outer side of the plumular metaxylem, forming buttresses as it were to the central xylem plate. The two phloem groups of the original diarch root-stele can still be identified, but they are isolated between the secondary tissues and the pericycle at a considerable distance from the centre of the section. The growth of Eranthis hiemalis from the seed has been followed by Irmisch with his usual care (24). Nothing can be added to his account of the external characters, but for convenience I will briefly describe a first-year seedling (PI. VI, Fig. i). The cotyledonary tube is very long, and the lower part is buried in the soil. Its base is inserted on a small tuber, which is spindle-shaped when first formed but later becomes globular. The plumule is quite rudimentary at this age : it is seated on the tuber and enclosed within the founded on the Sir uc hire of their Seedlings . 57 conical sheath formed by the base of the cotyledonary tube. The lower part of the tuber tapers off into the primary root. Irmisch describes the cotyledonary tube as hollow through- out, and speaks of the cavity enclosing the plumule as in communication with the outer air through the narrow tunnel which opens between the blades of the cotyledons ( 24 , p. 22 1)- In the series of sections cut by the microtome through the tuber and adjacent parts of three young seedlings, however, I find a diaphragm of thin-walled tissue above the extin- guisher-shaped sheath which encloses the plumule. The narrow bore of the tube itself is far less well outlined in transverse section than the plumular cavity, and is separated from it by the diaphragm just described. So far as can be determined from a number of hand-sections at different levels through the cotyledonary tube, it is hollow throughout, but one or more diaphragms may quite possibly exist above that which seals the plumular cavity. As the tuber increases in girth and the plumule in size, the base of the cotyledonary sheath is distended, and cracks appear in the diaphragm. These fissures may connect the cavities separated by the diaphragm, but only towards the end of the season when the cotyledons are withering. No part of the plumule appears above ground until the second season after germination, but at the end of the first summer it is no longer embryonic. The first foliage leaf is then completely formed and ready to push upwards on the approach of spring (Irmisch, 24 , Fig. 15). The massive bundles run the whole length of the cotyle- donary tube and are continued into the tuber (Irmisch). Any one of my three series of transverse sections through the tuber shows that it is simply the hypocotyl, swollen by the development of the cortex and conjunctive tissue into a storehouse for starch and other food-material. The vascular system of the first-year tuber is derived exclusively from the cotyledonary traces, for during the time that this system is developed the plumule is still so embryonic that the position of its procambial strands is not even indicated. The process 58 Sargant. — Theory of the Origin of Monocotyledons of tuber-formation in this species is thus quite distinct from that described in Delphinium sp. and Anemone coronaria. The increase of girth was there due to the formation of secondary tissue by a normal cambium, and the plumular traces took a large share in the formation of its vascular system. The behaviour of the cotyledonary traces when they enter the axis is indicated in Diagram X and very fully illustrated on Plates VI and VII. The sections drawn in Figs. 2-6 of PI. VI and Figs. 1 and 2 of PI. VII are from a single series cut through the tuber of A B m o*©*o Vi 2 ( « » \ O'* ^0 J Diagram X. a seedling younger than that outlined in Fig. 1, PI. VI. The bundles of the cotyledon show traces of double structure even before they leave the cotyledonary tube. There are traces of cambium between the phloem and xylem of each (PI. VI, Fig. 3). The compound nature of the traces becomes more clearly evident as they enter the tuber. A little lower down the phloem groups of each pair have drawn further apart, and the xylem elements are in three clusters : one internal to either group of phloem and one solitary between the other two (Fig. 4). This intermediate cluster then breaks up into two parts, and we have eight xylem and four phloem groups arranged symmetrically in two parallel straight lines, each of which is equidistant from the periphery of the section and its centre (Fig. 5). Down to this level the three complete series of sections founded on the Structure of their Seedlings . 59 which I have compared with each other agree in every detail. They are cut from three seedlings, of which A 6 , that outlined in Fig. 1 (PL VI), is the oldest, and A 2 , from which Figs. 2-6 are drawn, is the youngest. The intermediate seedling A 5 is nearly as old as A 6 . The course of the bundles in the region intermediate between Fig. 5, PL VI and Fig. 1 on Pl. VII is indicated in B, Diagram X. The details of the process differ slightly in the three seedlings cut. In all three the traces keep to a zone which lies about half- way between the periphery and the centre of the tuber, and their course downwards follows its outline, first curving out- wards and then closing in again. The formation of a phloem girdle is suggested even in A 2 , and is indicated much more completely in the older seedlings A 5 and A 6 . The four groups of xylem internal to the phloem groups (Fig. 5) show a tendency to split into two or even three strands. In seed- ling A 2 one only of the four xylem bundles splits in this way — the lowest in Fig. 5. When the four protoxylem groups of the early root-stele are in course of construction, which is always much lower down in the tuber, we find in A 2 that the xylem group in the lower left-hand corner of the section is being built up of three strands instead of two (Fig. 6). Moreover, an offshoot from the aberrant group of xylem has already ended blindly. The four corresponding xylem groups of seedlings A 5 and A 6 commonly split into two or more strands. To follow each minute cluster of xylem elements through a series of sections cut from a comparatively massive tuber is a task requiring some patience. I have done so in these three seedlings, and have convinced myself that the result may be fairly repre- sented by the generalized Figure B in Diagram X. The strands from each original group commonly unite again lower down : anastomoses with adjacent groups do occur, but are exceptional. The whole process is clearly an adaptation to the needs of the tuber. I suspected at first that a com- plete xylem network was indicated with which the first cauline roots would later be connected, but a series of sections 60 Sargant . — Theory of the Origin of Monocotyledons cut through a second-year tuber by Miss Thomas shows that no regular network exists there. The xylem strands are better developed than in the first-year tuber, but travel down- wards in the same isolated way. Where a cauline root is given off, the xylem strands in the immediate neighbourhood collect together and anastomose. The irregularities in the vascular system of first-year tubers affect the four xylem strands only which are in the neighbour- hood of phloem groups, and do not extend to the two pairs of slender xylem strands between them (x mi x m , in Fig. 5, PI. VI). Their behaviour is remarkably uniform in all three seedlings. Each pair is derived, as has been shown, from a single xylem strand, and the two halves reunite about halfway down the tuber, or even earlier. The two xylem groups thus formed on opposite sides of the tuber preserve their identity, and are continued downwards into the root, where they form the two permanent protoxylem groups of the root-stele. It is exceed- ingly rare to find any connexion between these xylem groups and the other strands scattered round the tuber. These scattered strands draw together in two groups, phloem and xylem alike, and form two bundles facing each other. Fig. 6 on PI. VI shows the orientation of such a stele in process of formation. To right and left are clusters of xylem elements unaccompanied by phloem, and with the protoxylem elements already external. To the north-east of the stele, as it were, is a slender bundle having an external phloem group, three lignified elements within it representing the primary xylem, and two radial rows of two unligni- fied elements each to represent the secondary formation. A similar group is in course of formation on the opposite side. At the base of the tuber the stele closes round the centre of the section, and a tetrarch xylem plate is formed. Two phloem groups only are present, and these are placed outside the two lateral protoxylem rays (px\ px', in Figs. 1 and 3 on PI. VII). The outermost elements of these rays can be traced backwards and identified as part of the primary forma- founded on the Structure of their Seedlings. 61 tion in the bundles of the tuber. There are often two or three unlignified secondary elements in rows outside them (PL VI I, Fig. 3). The two protoxylem groups which are flanked by phloem shortly die out, and the root is left with a diarch stele (PI. VII, Fig. 2). The vascular symmetry of Eranthis hiemctlis has already been compared with that of Anemarrhena (pp. 4 and 5, and Sargant, 35, PI. 2). The resemblance is clear from Diagrams VI and X. I will not go over the ground again. But some remarks may be offered on the difference between these types. The formation of a diarch root-stele in the typical Ranun- culaceous seedling is clearly connected with the insertion of a vigorous plumular stele on the comparatively insignificant cotyledonary traces, and the continuation of both into the persistent primary root (cf. Diagram IX). In plumule and root alike, secondary thickening is early developed and plays an important part. They are connected largely by means of secondary xylem, while the primary xylem of the cotyledon is continued downwards into that of the primary root. We may conceive a remote ancestor of the Ranunculaceae to have possessed four cotyledonary traces which regularly formed a tetrarch primary root by branching of the xylem according to Van Tieghem’s type 1, and that its comparatively slender plumular traces were inserted on two opposite traces of the hypocotyledonary stele. Then if the plumule began to in- crease in importance and develop earlier, its traces would exercise an increasing influence on the stele of the hypocotyl. The plumular phloem would by degrees unite with the adjacent cotyledonary groups, and thus form a single huge mass on either side of the stele. The secondary forma- tions produced by the action of plumular cambium between each mass of phloem and the cotyledonary xylem within it would in time arrest the development of the latter, and perhaps suppress it altogether. Finally, the root-stele would become completely diarch. The vascular systems of Albuca (p. 9), Chlorogalum , Anthericum , and Anthropodimn (p. 30) 6 2 Sargcint . — Theory of the Origin of Monocotyledons show how readily a tetrarch root-stele may become diarch by suppression of opposite protoxylem rays. The hypothetical vascular system at which we have now arrived corresponds very closely to the Ranunculaceous type (Diagram IX). In this two cotyledonary traces only enter the hypocotyl, but they give very clear evidence of their double origin, as M. Dangeard has already remarked (9). In every other respect the schemes are identical. Returning to the hypothetical Dicotyledon, whose seedling has a fourfold symmetry throughout its vascular system, let us suppose the development of the plumule to be arrested rather than accelerated, and secondary thickening to disappear altogether from the axis. This development of the vascular scheme leads to a symmetry closely resembling that of Anemarrhena. The latter indeed possesses but two cotyle- donary traces, but each gives very clear indications of its double origin when it enters the hypocotyl. To derive the vascular system of Eranthis hiemalis from our four-partite ancestor, we must suppose the plumule to have increased in importance up to a point at which the tetrarch symmetry of the root has almost disappeared. The whole vascular system was developing on Ranunculaceous lines. But at this point the ancestor of Eranthis parted company with its fellows. The plant perhaps had to adapt itself to different climatic conditions. These postponed the develop- ment of the plumule, and led to the formation of a tuber from the hypocotyl by the increase in mass of cortex and conjunctive tissue. This process gradually put a stop to secondary thickening by isolation of the bundles within the tuber, and the vascular system became what we see it in Eranthis . Little weight can be attached to hypothetical genealogies of this kind. They are valuable only as suggesting lines of research. In this case the investigation of forms allied to Anemarrhena on the one hand and to Eranthis on the other may yield valuable results. The seedlings of other species of Eranthis are, I believe, still undescribed even in their external characters. Their vascular structure is entirely unknown. founded on the Structure of their Seedlings . 63 The homology of the single seed-leaf of Ra 7 iunculus Ficaria (PI. VII, Fig. 4) has been much discussed. The reasons given by M. Sterckx ( 38 , p. 43) for. considering it a fusion of two cotyledons seem very strong. He points out that the venation of the bifid blade suggests its double origin. I have repeated his observations (Fig. 5) and agree in this conclusion. The blade is folded in the seed, and retains a well-marked median crease which is easily mistaken for the midrib in fresh material. But when the blade is blanched by immersion in methylated spirit, and has then been made transparent by treatment with phenol, the course of the veins can be accurately followed. Two main veins traverse the two segments of the blade respectively. Branches from both of these run upwards near the median crease, and when such branches unite with each other they sometimes appear to form a true midrib (B 15 Fig. 5). In other specimens its absence is clear (A 3 and A 4 , Fig. 5). The formation and maturation of the embryo within the seed has been followed and described with great care by M. Sterckx ( 38 , p. 42, and Figs. 151-9). The embryo in the ripe seed is very small. It is spherical, quite undifferentiated, and attached to a short suspensor. The cotyledonary member is lateral throughout its development. It is distinctly bi- lobed by the end of the summer in which the seed is sown. Throughout the following summer the development of the embryo continues within the seed. It germinates in the second spring, nearly two years after the seed was ripened. The ‘cotyledon’ comes above ground at once on germina- tion, and acts as the first assimilating organ. Its petiole is in a straight line with the hypocotyl and primary root. The lower limit of the hypocotyl is rather sharply defined externally by the sudden decrease in diameter of the axis where the primary root begins, but the upper limit cannot be determined until the position of the plumule is ascertained. It first appears as a slight swelling at the base of the cotyledon. Sometimes the first cauline root, always formed immediately below the plumule, shows first as a little tooth pointing 64 Sargant.- — Theory of the Origin of Monocotyledons downwards (Fig. 4, PL VII). The length of the hypocotyl defined by its external characters varies from 5 mm. to 1 mm., or even less in the seedlings I have examined. The external features of this seedling have been so fully described by Irmisch ( 21 , p. 1) and Sterckx ( 1 . c.) that I may go on at once to its vascular structure. The three seedlings A 3 , A 4 , and B 1? from which I have cut complete series of sections, agree with each other in every detail. That figured on PL VII is the youngest of the three. A single massive bundle runs down the whole length of the cotyledonary petiole. It is enclosed in a well-defined endodermis and contains a normal cambium layer. The phloem is a compact rounded strand, and there is a single protoxylem group, but the elements of the metaxylem form two distinct clusters separated by a few thin-walled cells. At the base of the cotyledon the petiole is bordered by two membranous wings which are united round the embryonic bud of the plumule into a closed sheath. At this level the cotyledonary trace has opened out slightly : the phloem mass is divided as well as the metaxylem. A single plumular trace joins it at the first node (Figs. 6 and 7). As they meet, the plumular trace becomes double and opens out in the same way as that from the cotyledon (Fig. 7). Very little below this both groups of protoxylem have become external, and a diarch root is constituted (Fig. 8). The process of transition recalls that found in Zygadenus. The length of the hypocotyl defined by its vascular characters does not exceed *5 mm. in any of the seedlings cut. The lateral position of the cotyledonary member is clearly an advantage to the plant. It allows the foliage leaves to develop unchecked by the necessity of bursting through a tubular sheath, as they must do in Delphinium nudicaule and Anemone coronaria. The ‘ cotyledon ’ of Ranunculus Ficaria may possibly have been derived from a tubular fusion such as that found in these plants. R.parnassifolius possesses a long cotyledonary tube (Winkler, 44 ), and R. millefoliatus a shorter one (Irmisch, 26 , p. 29). But it seems more likely that the founded on the Structure of their Seedlings . 65 two cotyledons from which the seed-leaf of R. Ficaria has been formed became united by one margin only from the first. M. Sterckx describes such a formation in Anemone apeninna ( 38 , Figs. 76, 77). An abnormal seedling of Ranun- culus repens in which the cotyledons are partly united by one margin is figured by Lord Avebury (Lubbock, 30 , vol. i. p. 90). I have found the cotyledons of R. Chius to be so united in the only three seedlings I have seen, but in no case more than halfway up the petioles. Sections through one such seedling of R. Chius show that the vascular structure is by no means unilateral at the base of the cotyledons. They are united into a shallow cup round the plumular bud, and a trace from each enters the short hypocotyl at opposite extremities of a diameter. The transition to a root-structure follows the usual Ranunculaceous type (Diagram IX). The same is true of Anemone nemorosa, in which the hypo- gaeic cotyledons have a false appearance of being inserted laterally so long as they are held together by the seed-coats. The few diagrams given by M. Sterckx of the vascular structure in A. apennina suggest that it may possess characters really intermediate between the usual type and that of Ranunculus Ficaria . Part III. General Considerations on the Origin of Monocotyledons. In the first Part of this paper I have given a full abstract of my observations on the vascular symmetry of Monocotyle- donous seedlings, and have attempted to show that the facts justify the following conclusions The vascular symmetry characteristic of the seedling in the monotypic genus Anemarrhena represents a type which is comparatively primitive among the Liliaceae. For many types of seedling structure found within that family can be shown with great probability to be derived from it, and the other types described are either clearly much modified by their environment, or so isolated systematically from the rest F 66 Sargant . — Theory of the Origin of Monocotyledons of the seedlings examined that the absence of intermediate links is of little weight. The Anemarrhena type of vascular structure is bisym- metrical throughout, and suggests a double origin for the cotyledonary members. The vascular symmetry of the seedlings examined from other Monocotyledonous families can be either derived from a Liliaceous type, or shown to be equally bisymmetrical. In the second Part I have described the vascular structure of a number of seedlings belonging to the Ranunculaceae which possess cotyledons more or less completely united to each other. When the united cotyledons are symmetrical with regard to the plumular axis — as in Eranthis hiemalis , Delphinium sp., and Anemone coronaria — their vascular struc- ture is bisymmetrical, and that of Eranthis bears a close resemblance to the structure of Anemarrhena. When the cotyledonary member is unilateral, as in Ranunculus Ficaria , its vascular structure is asymmetrical with regard to the axis. The strength of this comparison does not depend wholly on the suggestion of a real genetic relationship between Anemar- rhena and Eranthis for example, though I am inclined to think such a relationship probable, but rather lies in the fact that a partial union between two cotyledons does actually give rise to a reduced vascular system which bears a strong likeness to that existing in Anemarrhena and Albuca , a system already shown on comparative grounds to be in all probability the original of other Monocotyledonous types. The derivation of a seedling with unilateral vascular sym- metry, such as that of Zygadenus elegans , from a symmetrical form like Anemarrhena , has been justified by the examination of vascular systems intermediate between these extremes. The actual genealogy of Zygadenus is still of course con- jectural, but the a priori probability of such a descent is certainly increased by the analogy with Ranunculus Ficaria. The origin of the cotyledonary member in this species has already been fully discussed (p. 63). The conclusion there drawn from its external characters is that it has been formed founded on the Structure of their Seedlings. 67 by the union of two seed-leaves, which were distinct in a remote ancestor, and perhaps partially united in a more recent one. If this conclusion is justified, the vascular system of such ancestors would certainly be bilaterally symmetrical, and might probably resemble that of Eranthis. But in the seedling of R. Ficaria the vascular system of the cotyledon is unilateral in a very marked degree ; quite as one-sided as that of Zygadenus , which indeed it closely resembles. We need not be startled then by the presence of a midrib in the cotyledon of Zygadenus , nor by its lateral position with regard to the axis, since both characters are found in the seedling of Ranunculus Ficaria , together with independent evidence of the double origin of its cotyledon. The observations condensed in the first two Parts of this paper have led me to the conclusion that the single seed-leaf of the Liliaceae and allied orders is a compound member formed from the two seed-leaves of a remote ancestor. If this be admitted, the probability is that the seed-leaf of all Monocotyledons has a similar origin, and my observations on the Palms and Scitamineae confirm this view so far as they go. In the third and last Part of this paper I propose to discuss the whole theory of the origin of Monocotyledons which naturally arises from the view I have just expressed concern- ing the origin of their seed-leaf. This discussion will raise three questions, which can be treated separately : — 1. The comparative antiquity of the Monocotyledons and Dicotyledons. 2. Assuming the superior antiquity of Dicotyledons, can the single seed-leaf of Monocotyledons have arisen otherwise than by the fusion of two cotyledons into one member ? 3. Assuming the double origin of the seed-leaf in Mono- cotyledons, can we form any hypothesis as to the way in which the fusion first began, and concerning the correlation of this character with the others which distinguish Mono- cotyledons ? 68 Sargant. — Theory of the Origin of Monocotyledons i. Comparative Antiquity of Monocotyledons and Dicotyledons. The Angiosperms form a very well-defined group, and modern research has tended to show that the gulf between them and the Gymnosperms is even wider than was formerly supposed. To borrow an expressive phrase, we have begun to realize the isolation of the Angiosperms. Within this group the Monocotyledons are divided from the Dicotyledons by a number of natural characters, but these two classes are undoubtedly far more closely related to each other than is either of them to any other group of plants. The presumption is strong that they come from a common stock. A generation ago the Monocotyledons were regarded as probably the older group, but botanists have never been unanimous in this opinion, and of late the evidence of fossil botany has on the whole inclined the scale in the opposite direction. The case is so admirably summed up by Professor Bayley Balfour (in the article on Angiosperms, Supplement to Encyclopedia Britannica, vol. xxv, 1902), that I am tempted to quote his judgement in full : — ‘ The position of Angiosperms as the highest plant-group is unassailable. . . . We readily recognize in them now-a- days the natural classes of Dicotyledones and Monocotyle- dones, distinguished alike in vegetative and in reproductive construction, yet showing remarkable parallel sequences in development ; and we see that the Dicotyledones are the more advanced and show the greater capacity for further progressive evolution. But there is no sound basis for the assumption that the Dicotyledones are derived from Mono- cotyledones ; indeed the palaeontological evidence seems to point to the Dicotyledones being the older. This however does not entitle us to assume the origin of Monocotyledones from Dicotyledones, although there is manifestly a temptation to connect helobic forms of the former with ranal ones of the founded on the Structure of their Seedlings . 69 latter. There is no doubt that the phylum of Angiosperms has not sprung from that of Gymnosperms.’ The question so far then is open, and there is nothing in the present state of botanical knowledge to discredit the con- clusions which I have drawn from embryological evidence because they infer the superior antiquity of the seedling with two cotyledons. The development of the embryo within the seed has some- times been thought to show that the seed-leaf of Monocotyle- dons is a terminal member, and its plumule lateral. If this conclusion were well founded, it would be difficult to derive the Monocotyledonous embryo from a Dicotyledonous form. We should be almost forced to consider the one-leaved form as the more ancient. The two seed-leaves of a Dicotyle- donous embryo must then be derived from the splitting of the original terminal member. But the comparative work of Hegelmaier (14) and others has shown how little phylogenetic importance can be attached to details of structure in the embryo at this early age. In Corydalis ochroleuca , for example, there is a slight but un- doubted cleft in the embryo of the ripe seed which separates the cotyledons from each other, while in C. cava no such division exists. The embryo is Monocotyledonous from the first. The change from a Dicotyledonous to a Monocotyledonous habit must have taken place at a comparatively recent period in this case : more recent, that is, than the origin of Corydalis as a genus. Yet we know from the researches of Dr. Schmid 1 that no traces of the original bicotyledonary structure are to be found in the early history of the embryo of Corydalis cava. The very careful observations of M. Sterckx (38, p. 42) on the embryo of Ranunculus Ficaria up to the period of germination illustrate the same point. I have already referred to them (p. 63), and will only say here that the history of the embryo within the seed throws little light on the homology of the single cotyledonary member. Nothing in its develop- 1 Schmid, Beitrage zur Embryo-Entwickelung einiger Dicotylen. Bot. Zeit. 1902. Abth. I. p. 207. 70 Sargant . — Theory of the Origin of Monocotyledons ment contradicts the theory of its double origin, but I doubt whether that origin would have been suggested by the struc- ture of the embryo at any period had the union of the cotyledons in the mature organ been more perfect. Finally, Count Solms-Laubach ( 37 ) has shown that the cotyledon is not always apparently terminal in the embryo of Monocotyledons. In several genera belonging to the Com- melinaceae, and in Tamus communis , the plumule is terminal from the moment of its appearance, and the single seed-leaf lateral. Its development in these species resembles that of the cotyledonary member in Ranunculus Ficaria. These considerations are sufficient to throw doubt on the theoretical conclusions drawn by Mr. H. L. Lyon ( 31 ) from his interesting observations on the development of the embryo in a single species of Nelumhium . Professor Strasburger ( 39 , p. 510) has pointed out that the apparently lateral position of the growing-point described by Mr. Lyon in this species is probably due to the position of the embryo within the embryo- sac, and that the same cause might bring about the early fusion of both cotyledons into a single rudiment, though they are later quite distinct. 2. Homology of the Seed-leaf in Monocotyledons. Assuming that the seedling with one seed-leaf is derived from an ancestor with two, the change may have come about in one of two ways. One cotyledon of the pair may have been suppressed by degrees, or both have united to form a single member. The first alternative is that adopted by Mr. Henslow in 1892 ( 15 ). It has commonly been regarded as the only working hypothesis by the botanists who have seriously considered the possibility of deriving Monocotyledons from a Dicotyledonous stock. When in 1902 I published a short paper in the New Phytologist ( 35 ) giving an abstract of the reasons which led me to the conclusion that the single * cotyledon ’ of Mono- cotyledons was derived from both the cotyledons of a remote founded on the Structure of their Seedlings. 71 ancestor, I was not aware that this possibility had been suggested before. But a reference in Bernhardi’s paper of 1832 (4, p. 584) has recently led me to consult Agardh’s text-book (1, p. 197). Agardh proposes to class the embryos of all flowering plants in four main groups, thus : — ( Dicotyledones verae (all Dicotyledons except Dicotyledones < Nymphaeaceae). ( Polycotyledones (Coniferae). r . , , ( Syncotyledones . ryptocoty e ones ^ Monocotyledones (Gramineae). Under Syncotyledones he includes Lilieae, Aroideae, Naiadeae, Palmae, Scitamineae (p. 197), and afterwards mentions as belonging to the same class, Cycades and Nym- phaeaceae. This classification was probably influenced by the fact that Agardh did not distinguish clearly between the endosperm and the cotyledon in the Monocotyledonous embryo, and still less in that of the Nymphaeaceae. He treats the embryo with two seed-leaves as the type, and considers that of the Syncotyledones to be derived from it by the fusion of the two original seed-leaves into a thick fleshy mass. The Grasses are considered as the only true Monoco- tyledons because their seed-leaf has become single by the suppression of the second seed-leaf opposite to it. Thus Agardh derives the structure of the Grass-embryo also from a Dicotyledonous type. It is remarkable that the Monocotyledonous families men- tioned by Agardh as typical Syncotyledones (Lilieae, Naiadeae, Aroideae, Palmae, Scitamineae) are precisely those on which I have worked. His Lilieae probably include Irids and Amaryllids as well as the true Liliaceae. So far I have not examined any seedling from the Naiadeae, but with this exception we have the same horizon. I cannot therefore express any opinion as to the possibility of a distinct origin for the embryo of the Gramineae. It has been proposed 72 S organ t — Theory of the Origin of Monocotyledons in our own day to separate them from other Monocotyledons on embryological grounds (Van Tieghem, 44). The structure of some Ranunculaceous seedlings in which the cotyledons are partially united has already been described at length. The similarity between their vascular symmetry and that of a type of seedling primitive among the Liliaceae has led me to a conception of the Monocotyledonous embryo nearly identical with that of Agardh. This comparison has already been emphasized, but it must not be supposed that such partial union of the seed-leaves is confined to the Ranun- culaceae and their near allies. On the contrary, examples of such structure are recorded from many families, some widely separated systematically from the Ranunculaceae. The seedlings in which partial fusion of two cotyledons occurs may be divided into two classes of very unequal size. In the first, the cotyledons are united by both the margins of their petioles. These form a slender cylinder, which is not always hollow throughout its length. There is always a conical chamber at the base however, within which the plumular bud is developed. In the second class, the petioles are united by one margin only. The double member thus formed is always lateral with respect to the plumular axis. The formation of a cotyledonary tube in the first way has been recorded in a large number of species, but the literature of the subject is scattered. The following list makes no pretence to be exhaustive. I have included in it only those species of which I have seen figures, or descriptions sufficiently full to make the facts certain. The- references are to such descriptions : in the choice of authorities I have pre- ferred the more recent and more easily accessible, and have taken no account of priority in discovery. founded on the Structure of their Seedlings . 73 TABLE I. Dicotyledonous seedlings with a well-marked cotyledonary tube. Ranunculaceae. Anemone coronaria . . A. alpina A. blanda A. narcissiflora .... A. rupicola Ranunculus parnassifolius Trollius Ledebouri . . Eranthis hiemalis . . . Delphinium nudicaule D. hybridum (vars. puni- ceum, fissum, ochroleu- cum) Aconitum Anthora . . Berheridaceae . Leontice vesicaria (= L. Leontopetalon) L. aitaica (= Bongardia Rauwolfii) Podophyllum peltatum . P. Emodi Cruciferae. Cardamine (species from section Dentaria) Geraniaceae. Oxalis (tuberous species, as O. rubella and others) Irmisch, 23 , p. 1 (Fig.). Irmisch, 23 , p. 6 (Pdg.). Hildebrandt, 17 , p. 10 (Fig.). Hildebrandt, 17 , p. 18. Lubbock, 30 , I, p. 85. Winkler, 44 , p. 127. Lubbock, 30 , I, p. 91 (Fig.). Irmisch, 24 , p. 231 (Fig.). Sterckx, 38 , p. 51 (Fig.). Lubbock, 30 , I, p. 97 (Fig.). Darwin, 10 , p. 80. Sterckx, 38 , p. 59 (Fig.). Bernhardi, 4 , p. 574. Irmisch, 27 , p. 365 (Fig.). Bernhardi, 4 , p. 577 (Fig.). Bernhardi, 4 , p. 577. Holm, 19 , p. 419 (Fig.). Lubbock, 30 , I, p. 114 (Fig.). Dickson, 12 (Fig.). Bernhardi, 4 , p. 601. Hildebrandt, 17 , pp. 22 and 33 (Fig-)- Hildebrandt, 16 , PI. V. 74 Sargant . — Theory of the Origin of Monocotyledons Rhizophoreae. Rhizophora Mangle . Rh. conjugata .... Cucurbitaceae. Megarrhiza Californica, Torr. ( = Echinocystis fabacea) Umbelliferae . Smyrnium perfoliatum . S. rotundifolium . . . S. Olusatrum .... Bunium luteum (=Mu- retia tanaicensis) Chaerophyllum bulbo- sum Prangos ferulacea . . . Compositae. Serratula radiata . . . Primulaceae. Dodecatheon Meadia . . Polygonaceae . Polygonum bistorta . . P. sphaerostachyum . . Rheum Moorcroftianum Klebs, 29 , p. 562. Kerner and Oliver, I, p. 602 (Fig-)- Darwin, 10, p. 81 (Fig. 58). Lubbock, 30 , I, p. 597. Lubbock, 30 , II, p. 29 (Fig.). Lubbock, 30 , II, p. 24. Lubbock, 30 , II, p. 24. Holm, 20 , p. 66. Bernhardi, 4 , p. 607 (Fig.). Irmisch, 21 , p. 22 (Fig.). Bernhardi, 4 , p. 575 (Fig.). Winkler, 43 , p. 137 (Fig.). Bernhardi, 4 , pp.573, 578 (Fig.). Winkler, 43 (Fig.). Lubbock, 30 , II, p. 439. Holm, 18 . This list, though doubtless incomplete, contains no case which is not well authenticated 1 , and I have purposely omitted from it those species which possess a cotyledonary tube wide in proportion to its length, even when the length is consider- able. In such seedlings the plumule develops without diffi- 1 The petioles of the cotyledons in Megarrhiza Californica are said to be apparently connate but really separable (Lubbock, 30, I, p. 597). This does not agree with the description of Asa Gray, quoted by Darwin (10, pp. 81-3). founded on the Structure of their Seedlings. 75 culty within the cotyledonary tube, and their habit is not dissimilar from that of seedlings with distinct cotyledons. Short petiolar tubes are not uncommon among the seed- lings of species allied to those included in Table I. For example : Ranunculus millefoliatus (Irmisch, 26, p. 29, Fig. 1), Ferula foetida (Lubbock, 30, II, p. 37), Serratida tinctoria (Winkler, 41) Cotula coronopifolia (Lubbock, 30, II, p. 134), and Rheum officinale (Lubbock, 30, II, p. 442, Fig. 622). They link the numerous species in which the cotyledons are merely connate at the base with those in which the cotyle- donary tube is fully developed, and their existence is a strong argument for the derivation of such tubes from the fusion of two cotyledons, and not, as Professor D. H. Campbell has suggested (7, p. 11), from the division of one. From the first class of seedlings with united cotyledons we may now pass to the second. Ranunculus Ficaria and Anemone apennina (Sterckx, 38, pp. 34 and 80, Figs. 76, 77) are the only species with which I am acquainted in which the cotyledons are normally united by one margin only. Such unions are, however, not unfrequently found in abnormal specimens of species with distinct cotyledons. Ranunculus repens (Lubbock, 30, I, p. 90, Fig. 129) and R. Chius have been mentioned already. Irmisch found this abnormality in several seedlings of Phlomis tuherosa (22, p. 25, Fig. 105). Mrs. Stebbing has shown me a drawing of an abnormal seedling of Urtica dioica in which the blades as well as the short petioles of the two cotyledons are united by one margin. No doubt such instances could be multiplied. Their interest lies in the possibility they suggest that the single seed-leaf of some species among those Dicotyledons which possess but one may be formed in a similar way. The seed-leaf of Pinguicula vulgaris , for example, looks in Buchenau’s figures (6, Figs. 1 and 2) as if it might be derived from the union of two cotyledons by one margin only. Dickson (11) states that P. grandiflora also germinates with a single seed-leaf, the blade of which is bifid. P . caudata and P. lusitanica have separate cotyledons. 76 Sargant. — Theory of the Origin of Monocotyledons The following list of the best-known pseudo-monocotyledons is no doubt very imperfect. The only species in it which I have examined is Cyclamen persicum . Its vascular structure suggests very strongly that the cotyledonary member consists of two seed-leaves united into a solid tube, but until the structure of allied genera has been worked out no great weight can be attached to this observation. Bernhardi (4, p. 578) suggests this origin of the single seed-leaf on the ground that the cotyledons of Dodecatheon Meadia are united into a tube. Lord Avebury remarks that when Cyclamen is raised from seed abnormal specimens are not uncommon in which the cotyledons have divided blades (Lubbock, 30, II, p. 184). TABLE II. Pseudo-monocotyledons. Fiimariaceae. Corydalis tuberosa, D.C. ( = C. solida and C. cava) . . C. fabacea Dicentra Cucullaria, Bernh. (= Capnorchis Cucullaria) Irmisch, 25 (Fig.). Bischoff, 5 (Fig.). Irmisch, 25 (Fig.). Irmisch, 25. Umbelliferae. Carum Bulbocastanum . . C. alpinum, Benth. and Hook. (= Bunium petraeum, Ten.) Erigenia bulbosa, Nutt . . Primulaceae. Cyclamen persicum .... L en tibidarieae . Pinguicula vulgaris . . P. grandiflora Irmisch, 21, p. 17 (Fig.). Bernhardi, 4, p. 575. Holm, 20, p. 63. Darwin, 10, p. 78 (Fig. 57). Lubbock, 30, II, p. 184. Bernhardi, 4, p. 583. Buchenau, 6, p. 64 (Figs. 1 and 2). Dickson, 11. Dickson, 11. founded on the Structure of their Seedlings . 77 Nyctagineae. Abronia umbellata .... Darwin, 10 , p. 95 (Fig. 61). Klebs, 29 , p. 561 (Fig. 10). A. arenaria Klebs, 29 , p. 560. A. grandiflora Klebs, 29 , p. 560. The existence of some Dicotyledons with only one seed- leaf is commonly explained by the supposition that one seed-leaf of the pair is abortive. This may be so in some of the species in the foregoing list, as Abronia umbellata (see Darwin, 10 , p. 95) : other cases may arise through the fusion of cotyledons by one or both margins. 3. Origin of the Monocotyledonous Habit. If the homology of the single seed-leaf in Monocotyledons with both the seed-leaves of Dicotyledons be accepted as a working hypothesis, we are at once confronted with another question. How did that fusion begin, and of what ad- vantage was it to the ancestral Monocotyledons in which it became stereotyped ? That the union of seed-leaves does offer advantages to seedlings under certain conditions is clearly shown by the existence of a number of Dicotyledonous species in which they are normally united for a great part of their length. Comparison of the species mentioned in Table I with each other shows that they have another character in common besides the possession of a cotyledonary tube. With one exception their hypocotyl is always much reduced in length, and is commonly thickened. As a rule the first internodes of the plumular axis are likewise more or less completely suppressed. Rhizophora is said to have an elongated hypo- cotyl, but the conditions under which it grows in tropical swamps are unique, and we cannot be surprised by exceptional adaptations to them. The great majority of the species mentioned are tuberous : the others (. Podophyllum , Serratula, Polygonum , Rheum) form 78 Sargant . — Theory of the Origin of Monocotyledons an upright much shortened subterranean axis in which the first internodes of the stem, as well as the hypocotyl, are suppressed. The species of Anemone and Oxalis with united cotyledons are distinguished from their neighbours within those genera by their tuberous habit. M. Sterckx remarks that among the Ranunculaceae the species with concrescent cotyledons have short subterranean hypocotyls which are generally tuberous ( 38 , pp. 80, 81). The explanation he gives is that the united petioles of the cotyle- dons carry their blades upwards, and thus replace the elongated aerial hypocotyls of allied species. Lord Avebury gives a similar reason for the correlation of a tuberous hypocotyl with concrescent cotyledons among the Umbelliferae (Lubbock, 30, 1 1 , pp. 23, 24). Darwin speaking of several pseudo-monocotyle- dons, together with some other species in which both cotyledons are very much reduced in size or even absent altogether, says : ‘ From the several cases now given, which refer to widely different plants, we may infer that there is some close connexion between the reduced size of one or both cotyledons and the formation by the enlargement of the hypocotyl or of the radicle of a so-called bulb.’ He attributes this to correlation of growth : the expenditure of material in the formation of a bulb or tuber is balanced by the economy effected in the reduction of cotyledonary tissue (10, p. 97). The pseudo-monocotyledons of Table II are in fact also characterized by the early formation of tubers, or at least by the development of a much shortened squat axis. The formation of underground root-stocks, of tubers, corms, and bulbs, is characteristic of the plants called ‘ geophilous 5 by Professor Areschoug ( 3 ). The general definition of the term which he gives on page 1 is very wide : 4 We include under that head such plants as form the buds by which they re- produce the shoot underground : those plants in fact which develop their aerial organs more or less completely beneath the surface of the soil.’ Defined in this way the term would include all biennials and herbaceous perennials of the temperate and arctic zones, for the aerial shoots of all such plants dis- founded on the Structure of their Seedlings. 79 appear during the winter, and are replaced in the following spring by the development of buds formed underground. Geophilous characters are shown most clearly by plants which put forth aerial shoots during a short annual season only. Such are the two classes of plants termed ‘ alpines’ and ‘ bulbs ’ by gardeners. The underground organs of such plants attain to some size, not unfrequently exceeding that of the aerial shoot. They are native to situations which have a short annual period in which the conditions are favourable to vegetation, and a longer dead season. The short hot summer of the arctic regions and of alpine summits, which does not begin until the snow melts, and is followed by a long frost-bound winter ; the summer in the interior of South Africa, ushered in by rains, and followed by a season of dry cold ; the damp warm spring of the Mediterranean region succeeded by a hot dry summer ; these are examples of climatic conditions favourable to highly specialized geophytes, and within such regions the habit was no doubt developed. In order to use the short season of vegetation to the best advantage the geophilous plant or geophyte must be furnished with a store of nourishment, and this is placed at some distance below the surface of the soil for protection against the cold or heat of the dead season. A plant so provided can throw up leaves and flowers at a few days’ notice from the bud attached to its swollen axis or tuberous root. The leaves when once above the ground make the most of their short life. They restock the underground organs with food for the following season, and they support the flowers, and later the maturing fruit, until the seed is ripe. When this occurs before the advent of the cold or drought withers the aerial shoots, the cycle of development is complete, but in such localities it must often happen that an early frost or a dry season kills all the seed formed by a plant before it is ripe. The fact that all the species mentioned in Table I, with the exception of Rhizophora , are highly specialized geophytes suggests very strongly that union of the cotyledons is an 8o Sargant.— Theory of the Origin of Monocotyledons adaptation to this habit. When we consider the conditions under which a typical geophyte lives, it is very clear that its seedlings must be even more perfectly adapted to the environ- ment than the mature plant in order to have a chance of surviving. The seed formed at the end of the growing period is commonly capable of resisting a considerable degree of cold or drought in the long dead season. When the genial weather returns and it germinates, the seed is confronted with a difficult problem. During the short period of vegetation the growth of the seedling must proceed in such a way that the structure completed by the end of the season is capable of living through the severe weather which follows. Accordingly we find that the seedling begins at once to form its underground organs. Not unfrequently the whole structure remains underground during the first season of growth (Megarrhiza Californica, Darwin, 10 , p. 82 ; Arum maculatum, Rimbach, 33 ). More commonly the cotyledons only appear above ground in the first season (E rant his hiemalis , Fritillaria imperialis), or the cotyledons may remain underground in the seed and the first leaf break through the soil {Anemone nemorosa, Irmisch, 23 , p. 17, Figs. 26-28 ; Eucomis nana, Jacq.). In other species both cotyledons and foliage leaves come up above ground in the first season and act as assimilating organs {Delphinium nudicaule, Iris sp.). In all these cases, however, the production of assimilating surfaces seems to be an object of secondary importance to the seedling of a geophilous plant in its first season. The forma- tion of adequate subterranean organs at a safe distance below the surface of the soil is the condition on which the life of such a seedling ultimately depends, and its powers are devoted in the first place to this task. Concrescent cotyledons seem to be an adaptation for pro- ducing effective assimilating surfaces with the least possible expenditure of material (Lubbock, Sterckx, 1 . c.). The pro- duction of a single cotyledon, whether by the more complete fusion of two or in any other way, is also an economy as founded on the Structure of their Seedlings . 81 compared with the formation of two cotyledons (Darwin, 1. c.). It is true that in time the extra assimilating surfaces will more than repay the cost of their production, but time may fail the geophyte which dares not risk being caught by the bad weather unprepared. These considerations have led me to look upon the Mono- cotyledon as an organism adapted primarily to a geophilous habit. The single cotyledon has been shown to be connected with this way of life in some Dicotyledons, and many of the features which distinguish Monocotyledons from Dicotyledons may be explained as having been formed under the conditions I have just described. Since I have adopted this view as a working hypothesis, the purpose of many details in the structure of Monocotyledons which had puzzled me before has become comprehensible. Distribution of the Bundles in the Stem . An erect subterranean axis with much shortened inter- nodes and crowded with the sheathing bases of leaves must inevitably receive a number of traces from each leaf, and these traces — entering the axis in segments of its cir- cumference corresponding to the breadth of the leaf-base — would naturally arrange themselves in more or less complete concentric circles. Mr. Henslow has well described the process by which this might occur (15, p. 512), but his suggestions are much more applicable to a short vertical subterranean axis such as that found in the four-year-old seedling of Podophyllum (Holm, 19) than to the rhizome of Nymphaea. In a squat underground root-stock secondary growth of the xylem in thickness would be useless : the bundles are essentially channels of communication between the leaves and the roots, and they are not required to support a great mechanical strain. Thus the extra-fascicular cambium would first disappear — as it has done in Podophyllum — and later the cambial zone from each bundle. The bundles of Podophyllum possess distinct fascicular cambium, but they are isolated from each other by the well-marked bundle-sheaths. 82 Sargant. — Theory of the Origin of Monocotyledons Miss Anderssoa (2) and M. Queva (33) have found a well- defined cambial zone within the bundles of some Mono- cotyledons, and traces of such formation in many others. The tuber of Corydalis solida (Jost, 28) appears to retain normal secondary growth in thickness. The cambium forms a new tuber every year within the old one, adding to the wood a great mass of parenchymatous elements which become filled with reserve food-material. The anatomy of Dicotyle- donous tubers has been somewhat neglected, but I believe this structure to be exceptional. The seedling anatomy of Delphinium sp. and Anemone coronaria suggests that it may be found in the mature tubers of these species also (pp. 54-56). The food supply, however, is more commonly stored in the con- junctive tissue and cortex ( Eranthis , Podophyllum , Cyclamen , and the roots of Ranunctdus Ficaria). The development of the cortex and conjunctive tissue inevitably isolates the bundles traversing the tuber. Early disappearance of the Primary Root . This character is by no means universal among Mono- cotyledons. In many arborescent species the primary root persists for a considerable time, becoming stout and well developed (Yucca, Palms). But the rule among bulbous and herbaceous species certainly is that the primary root dis- appears at the same time with the cotyledon. Bulbous plants as a rule lose their roots at the end of each growing season, and put out new ones at the beginning of the next. This habit is no doubt correlated with the direct connexion of each leaf with a particular root so characteristic of bulbous plants (cf. a quotation from Mirbel given by Mr. Henslow, 15, p. 506). The annual crop of roots is clearly bound up with the annual recurrence of a period of vegetative activity. Eranthis agrees in this respect with Monocotyledons. The primary root is replaced in the second spring by a circle of roots developed in a girdle surrounding the tuber (Irmisch, 24, Fig- !5)- founded on the Structure of their Seedlings. 83 Absence of a true Epidermis in the Root above the Root- sheath. This character of the root is so far as we know universal among Monocotyledons, but not confined to them. It is found in the Nymphaeaceae among Dicotyledons. I can form no guess as to its origin. Parallel Venation of the Leaves . Parallel venation is general among the leaves of Mono- cotyledons, but by no means universal. Professor Areschoug has remarked that the linear leaves characteristic of most bulbous Monocotyledons are better adapted to push upwards through the soil than any Dicotyledonous type of leaf ( 3 , p. 55). The bulb seems in many respects to be the most highly specialized form of geophyte: its squat axis and pointed leaves with their broad sheathing base are clearly adaptations to a geophilous life. The anatomy of the stem and the short life of the roots are characters correlated with those just mentioned. The Ternary Symmetry of the Flower. The three-whorled flower is very generally found among Monocotyledons, but is not universal. Many of the exceptions may be derived from it by reduction (Aroideae). No connexion between this symmetry and a geophilous habit occurs to me, except that the parts of the flower may perhaps pack easily into a bud when arranged in this way. The presence of an Endosperm in the Seed. This character is neither universal among Monocotyledons nor confined to them, but it is much more common in this class of plants than among Dicotyledons. I believe it to be a character common to the majority of highly specialized geophytes. This is illustrated by the fact that among the twenty-seven Dicotyledonous genera mentioned in Tables I and II, three only ( Card amine, Serratula , and Pinguicula ) 84 Sargant. — Theory of ihe Origin of Monocotyledons possess exalbuminous seeds. The connexion is not difficult to understand. The seed of geophilous plants must become ripe within a short period, and the embryo therefore remains small, and commonly but little differentiated, while the endo- sperm is packed with food-stuff. With this is connected the slow germination of many species with concrescent cotyledons. The prolonged maturation of the embryo within the seed of Ranunculus Ficaria — a process extending over nearly two years after the seed is ripe — has been mentioned already. It is fully described by M. Sterckx ( 38 , p. 42, Figs. 1 51-160). A similar maturation of the embryo takes place in the seeds of Eranthis hiemalis , Corydalis cava (Schmid, 1 . c.), and of several species of Anemone after they are shed, but here the process is complete at the end of the first season and the seeds germinate in the following spring (Sterckx, 38 , p. 79). M. Sterckx’ observations, however, were made on plants growing in a temperate climate with a long summer. It is very probable that the seeds of these species if shed at the end of a short alpine or arctic summer might defer the maturation of their embryos to the next year, and germinate only in the second summer after dispersal. The slow germination of many Monocotyledonous seeds, par- ticularly those belonging to bulbous species, is a fact familiar to all gardeners. The suggestions here made as to the origin of Mono- cotyledons from a Dicotyledonous stock will perhaps be thought worthy of consideration by botanists. It is certain that if the theory be adopted as a working hypothesis it will suggest new lines of research, for example a more complete investigation of the embryology of Monocotyledons and the anatomical investigation of geophilous Dicotyledons. Not less important is the study of seedlings and immature plants in the field, in continuation of the work of Irmisch, Holm, and others. founded on the Structure of their Seedlings . 85 Index to Species mentioned. Abronia arenaria, 77. Abronia grandiflora, 77. Abronia umbellata, 77. Acanthophoenix crinita, 48. Aconitum Anthora, 73. Agave Rovelliana, 42. Agave spicata, 41. Albuca Nelsoni, 9, 23. Allium angulosum, 32. Allium ascalonium, 31. Allium Cepa, 31. Allium neapolitanum, 31. Allium Porrum, 31. Allium serufschanicum, 31. Aloe Buchanii, 38. Alstroemeria (gar. var.), 41. Amomum angustifolium, 50. Anemarrhena asphodeloides, 4, 26. Anemone alpina, 73. Anemone apennina, 65, 75. Anemone blanda, 73. Anemone coronaria, 56, 73. Anemone narcissiflora, 73. Anemone nemorosa, 65, 80. Anemone rupicola, 73. Anthericum Liliago, 29. Anthurium Bakerianum, 2, 40, 45 . Areca sapida, 48. Arisaema speciosum, 45. Arthropodium cirrhatum, 30. Arum maculatum, 44, 80. Asparagus decumbens, 37. Asparagus officinalis, 37. Asphodeline liburnica, 26. Asphodelus albus, 27. Asphodelus cerasifer, 27. Asphodelus fistulosus, 27. Bloomeria aurea, 32. Bongardia Rauwolfii, 73. Bravoa geminiflora, 41. Brodiaea lactea, 32. Bulbine annua, 9, 28. Bunium luteum , 74. Buniurn petraeum , 76. Canna sp., 50. Capnorchis Cucullaria , 76. Cardamine (Dentaria), 73, 84. Carum alpinum, 76. Carum Bulbocastanum, 76. Chaerophyllum bulbosum, 74. Chamaerops Fortunei, 49. Chamaerops humilis, 49. Chlorogalum pomeridianum, 29. Cordyline australis, 34. Corydalis cava , 69, 76, 84. Corydalis fabacea, 76. Corydalis ochroleuca, 69. Corydalis soli da, 76, 82. Corydalis tuberosa, D.C., 76. Cotula coronopifolia, 75. Cyclamen persicum, 76. Delphinium Jissum, 73. Delphinium hybridum, 73. Delphinium nudicaule, 54, 73, 80. Delphinium ochroleucum, 73. Delphinium puniceum , 73. Delphinium Requienii, 53. Delphinium sp., 54. Dentaria , 73, 83. Desmoncus minor, 48. Desmoncus sp., 48. Dicentra Cucullaria, 76. Dipcadi serotinum, 12. Dodecatheon Meadia, 74. Doryanthes excelsa, 42. Doryanthes Palmeri, 42. Dracaena Draco, 36. Echinocystis fabacea, 74. Elettaria cardamomum, 50. Eranthis hiemalis, 5,56, 73, 80,82, 84. Eremurus spectabilis, 27. Eremurus turkestanicus, 27. 86 Sargant. — Theory of the Origin of Monocotyledons Erigenia bulbosa, Nutt., 76. Erythronium Hartwegi, 23, 25. Eucomis nana, Jacq., 18, 80. Euterpe edulis, 50. Ferula foetida, 75. Freesia sp., 44. Fritillaria alpina, 25. Fritillaria imperialis, 23, 80. Galtonia candicans, 12. Geonoma oxycarpa, 49. Hyacinthus orientalis, 20. Hyacinthus romanus, 14. Iris Boissieri, 43. Iris sibirica, 43. Iris sp., 43, 80. Lachenalia Nelsoni, 21. Leontice altaica , 73. Leontice Leontopetalon, 73. Leontice vesicaria, 73. Lilium croceum, 25. Lilium Henryi, 25. Lilium sp., 25. Megarrhiza californica , 74, 80. Milla biflora, 32. Muretia tanaicensis, 74. Musa Livingstonia, 50. Muscari armenaicum, 16. Muscari atlanticum, 15. Muscari comosum, 20. Muscari neglectum, 18. Nelumbium, 70. Nigella damascena, 53. Ornithogalum exscapum, 21. Ornithogalum sulphureum, 20. Oxalis, 73. Phlomis tuberosa, 75. Phoenix dactylifera, 49. Pinguicula caudata, 75, 83. Pinguicula grandiflora, 75, 76, 83. Pinguicula lusitanica, 75, 83. Pinguicula vulgaris, 75, 76, 83. Podophyllum Emodi, 73, 77. Podophyllum peltatum, 73, 77, 81. Polygonum bistorta, 74, 77. Polygonum sphaerostachyum, 74, 77 - Prangos ferulacea, 74. Ranunculus Chius, 65. Ranunculus Ficaria, 63, 75. Ranunculus millefoliatus, 64, 75. Ranunculus parnassifolius, 64, 73. Ranunculus repens, 65. Renealmia racemosa, 50. Rheum Moorcroftianum, 74, 77. Rheum officinale, 75, 77. Rhizophora conjugata, 74, 77. Rhizophora Mangle, 74, 77. Scilla festalis, 20. Scilla peruviana, 21. Scilla sibirica, 20. Serratula radiata, 74, 77, 83. Serratula tinctoria, 75, 77, 83. Smyrnium Olusatrum, 74. Smyrnium perfoliatum, 74. Smyrnium rotundifolium, 74. Tamus communis, 9, 70. Thrinax excelsa, 48. Tricyrtis hirta, 33. Trillium grandiflorum, 34. Trollius Ledebouri, 73. Tulipa praecox, 25. Tulipa sp., 25. Urtica dioica, 75. Veratrum nigrum, 33. Yucca aloifolia, 35, 39. Yucca arborescens, 35. Yucca gloriosa, 36, 39. Zygadenus elegans, 32. founded on the Structure of their Seedlings . 87 References to Literature. 1 . Agardh, C. A. : Larobok i Botanik. Part I. Malmo, 1829-32. 2 . Andersson, S. : Ueber die Entwickelung der primaren Gefassbiindelstrange der Monokotylen. Bihang till K. Sv. Vet. Akad. Handl., Bd. xiii, 1888. (Full abstract in Bot. Centralblatt, vol. xxxviii, 1889, pp. 586 and 618.) 8. Areschoug, F. W. C. : Beitrage zur Biologie der geophilen Pflanzen. Lund, 1896. 4 . Bernhardi : Ueber die merkwiirdigsten Verschiedenheiten des entwickelten Pflanzenembryos und ihren Werth fiir Systematik. Linnaea, vol. vii, 1832. 5 . Bischoff, G. W. : Beobachtungen iiber den Gang des Keimens . . . bei Cory- dalis-Arten. Tiedemann’s Zeitschr. f. Physiologie, Bd. iv, 1831, p. 146. 6. Buchenau, Fr. : Morphologische Studien an deutschen Lentibularieen. Bot. Zeit., 1865, p. 64. 7 . Campbell, D. H. : On the Affinities of certain anomalous Dicotyledons. American Naturalist, vol. xxxvi, 1902, p. 7. 8. Chaveaud, G. : Passage de la position alterne a la position superpos^e de l’appareil conducteur . . . dans le cotyledon de l’oignon (Allium cepa). Bull. Mus. Hist. Nat. Paris, 1902, p. 52. 9 . Dangeard, P. : Recherches sur le mode d’union de la tige et de la racine. Le Botaniste, I, 1889. 10 . Darwin, Ch. : The Power of Movement in Plants. London, 1880. 11 > Dickson, A.: On the Development of the Flower of Pinguicula vulgaris, L., with remarks on the embryos of P. vulgaris, P. Grandiflora, P. lusitanica, P. caudata and Utricularia minor. Trans. Roy. Soc. Edin., vol. xxv, 1869, p. 639. (Abstract in Bot. Zeit., 1870, p. 220.) 12. On the Germination of Podophyllum Emodi. Trans. Bot. Soc. Edinburgh, vol. xvi, 1882. 13 . GIsrard, R. : Recherches sur le passage de la racine a la tige. Ann. d. Sci. Nat., ser. vi, Botanique, 1881, p. 279. 14 . Hegelmaier, F. : Vergleichende Untersuchungen iiber Entwickelung dikoty- ledoner Keime. Stuttgart, 1878. 15 . Henslow, G. : A Theoretical Origin of Endogens from Exogens by Self- Adaptation to an Aquatic Habit. Linn. Soc. Joum., xxix, 1892, p. 485. 16 . Hildebrandt, F. : Die Lebensverhaltnisse der Oxalis-Arten. Jena, 1884. 17 . s I — Einige Beobachtungen an Keimlingen und Stecklingen. Bot. Zeit., 1892. 18 . Holm, Theod. : Contributions to the Knowledge of the Germination of some North American Plants. Mem. of the Torrey Bot. Club, vol. ii, 1891. 19 . Podophyllum peltatum : a morphological study. Bot. Gazette, vol. xxvii, 1899, p. 419. 20 . Erigenia bulbosa, Nutt. A morphological and anatomical study. Amer. Journ. of Science, Jan. 1901. 21 . Irmisch, Thilo : Beitrage zur vergleichenden Morphologie der Pflanzen. Abth. 1. Halle, 1854. 88 Sarg ant . — T heory of the Origin of Monocotyledons . 22. Irmisch, Thilo : Beitrage zur vergleichenden Morphologie der Pflanzen. Abth. 2. Halle, 1856. 23 . — Ueber einige Ranunculaceae. Bot. Zeit., 1856. 24 . Ueber einige Ranunculaceae. Bot. Zeit., i860. 25 . — Ueber einige Fumariaceae. Abhandl. d. Naturf. Gesell. Halle, Bd. vi, 1862. 26 . — Ueber einige Ranunculaceae. Bot. Zeit., 1865. 27 . — Einige Bemerkungen iiber Aconitum Anthora. Abhandl. v. naturwiss. Vereine zu Bremen, Bd. iii, 1873, p. 365. 28 . Jost, L. : Die Erneuerungsweise von Corydalis solida, Sn. Bot. Zeit., 1890, P- 2 57 * 29 . Klebs, G. : Beitrage zur Morphologie und Biologie der Keimung. Unters. a. d. Bot. Inst, zu Tubingen, Bd. i, Leipzig, 1881-5, P- 53 6 * 80 . Lubbock, Sir J. : A Contribution to our Knowledge of Seedlings. London, 1892, vols. i and ii. 31 . Lyon, H. L. : Embryogeny of Nelumbo. Minnesota Bot. Studies, ii, p. 643, 190T. 32 . Qutf.VA, C. : Contributions a Panatomie des Monocotylifdonees. Trav. et Mem. de l’Universite de Lille, 1900. 33 . Rimbach, A. : Ueber die Lebensweise des Arum maculatum. Ber. d. deutsch. bot. Gesell., 1897. 34 . Sargant, E. : A new Type of Transition from Stem to Root in the Vascular System of Seedlings. Ann. of Bot., vol. xiv, 1900, p. 633. 35. The Origin of the Seed-Leaf in Monocotyledons. New Phytologist, vol. i, 1902, p. 107. 86. Scott, R., and Sargant, E. : On the Development of Arum maculatum from the Seed. Ann. of Bot., vol. xii, 1898, p. 399. 37 . Solms-Laubach, Graf zu : Ueber monocotyle Embryonen mit scheitel- biirtigem Vegetation spunkt. Bot. Zeit., 1878, p. 65. 38 . Sterckx, R. : Recherches anatomiques sur l’embryon et les plantules dans la famille des R^nonculacees. Mem. de la Soc. roy. d. Sci. de Liege, ser. iii, tom. ii, 1899. 89 . Strasburger, E. : Ein Beitrag zur Kenntniss von Ceratophyllum submersum und phylogenetische Erorterungen. Prings. Jahrb., vol. xxxvii, 1902, P- 477 - 40 . Tansley, A. G. : ‘ Reduction ’ in Descent. New Phytologist, vol. i, 1902, P- J 3 I- 41 . Van Tieghem, Ph. : Morphologie de l’embryon et de la plantule chez les Graminees et les Cyperacees. Ann. d. Sci. Nat., s£r. viii, tom. iii, 1897, p. 259. 42 . Winkler, A. : Ueber die Keimblatter der deutschen Dicotylen. Verhandl. d. bot. Vereins d. Provinz Brandenburg, Bd. xvi, 1874. 43 . Ueber einige Pflanzen der deutschen Flora deren Keimblatt- stiele scheidig verwachsen sind. Ibid., Bd. xxvii, 1885. 44 . Die Keimpflanze des Ranunculus parnassifolius. Ibid., xxxv, 1893, p. 160. Anomale Keimungen. Ibid., xxxvi, 1894, p. 127. 45 . founded on the Structure of their Seedlings . 89 EXPLANATION OF FIGURES IN PLATES I-VII. Illustrating Miss Sargant’s paper on the Origin of Monocotyledons. The figures on Plates I and II are drawn by Miss E. Sargant, with the ex- ception of Fig. 5 on Plate I (Miss E. N. Thomas). The figures on Plates III-VII are drawn by Miss Agnes Robertson, with the exception of those marked (E. S.) or (E. N. T.). PLATE I. Albuca Nelsoni. Fig. 1. Outline of whole seedling A 5 , drawn from life. x 1 / l . Outline of young bulb and adjacent parts from seedling B u preserved in spirit, x 1 / 1 . Fig. 2. From microtome series through seedling A s . Transverse section of embryonic stem-bud enclosed in expanded base of cotyledon, x 75. Fig. 3. From same series, *16 mm. below Fig. 2. Transverse section through transitional region. Each main cotyledonary trace has formed three protoxylem groups: px v px iy px. iy and. px iy px 2 ' , px z . x 210. Fig. 4. From same series, *12 mm. below Fig. 3. Triarch root forming, but original tetrarch structure indicated by presence of protoxylem group px z +pxj. X 210 . Hyacinthus romanus. Fig. 5. Outline of seedling A 5 , from life, x 1 / i . (E. N. T.) Fig. 6. From microtome series through seedling A 5 . Transverse section through embryonic stem-bud enclosed in expanded base of cotyledon. Two main bundles, M lf M 2y and four lateral strands in cotyledon, x 75. Fig. 7. From same series, *27 mm. below Fig. 6. Formation of phloem girdle indicated. Two lateral bundles, / t , / 2 , unite with main bundles, M ly M 2 , to form stele, x 225. Fig. 8. From same series, *04 mm. below Fig. 7. The whole xylem of bundles l ly l 2 , has joined the lowest group derived from the main bundles, px z +px z . x 225. Fig. 9. From same series, .13 mm. below Fig. 8. Tetrarch root-stele. The last- formed group of protoxylem,/^, is smaller than the others, x 225. PLATE II. Muscari atlanticum . Fig. 1. Outline of seedling A ly preserved in spirit, x 1 / 1 . Fig. 2. From microtome series through seedling A±, just below first node. Two main cotyledonary traces, M ly M 2 , and two lateral ones, l L} l 2y in stele, x 200. Fig. 3. From same series, -03 mm. below Fig. 2. Pentarch root-stele indicated. The two lateral traces (/ x , l 2 in Fig. 2) have supplied the lowest phloem group, x 300. 90 Sargant . — Theory of the Origin of Monocotyledons Muscari armenaicum. Fig. 4. Outline of seedling A 3 , drawn from life, x' l / x . Fig. 5. From microtome series through seedling A 3 , at base of first node. The lateral trace l 3 is inserting itself on l x . The two main traces, M x , M 2 , are united by the common protoxylem group, px 2 +px 2 . x 200. Fig. 6. From same series, .07 mm. below Fig. 5. Pentarch root-stele indicated. The lateral traces supply the two lower phloem groups and the protoxylem group between them, px 5 , with part of two others. x 300. Fig. 7. Outline of seedling A 5 , drawn from life, x 1 / x . Fig. 8. From microtome series through seedling A h , just below first node. Two main cotyledonary traces, M x and M 2 , and two lateral ones, l x , l 2 . x 200. Fig. 9. From same series, -07 mm. below Fig. 8. Tetrarch root-stele indicated. The lateral traces (l x , l 2 , in Fig. 8) form half the stele, supplying the two lower phloem groups — which are sensibly smaller than the upper ones — the whole of the protoxylem group px 5 , and part of groups px 3 and pxj. x 300. PLATE III. Fritillaria imperialis. Fig. 1. Outline of seedling A x , drawn from life, x 1 / 1 . Fig. 2. From microtome series through seedling A x . Transverse section through enlarged base of cotyledon, enclosing young stem-bud. Two massive bundles, M x , M 2 , in cotyledon : three strands in first leaf, x 66. Fig. 3. From same series, -32 mm. below Fig. 2. First node. Two plumular traces are inserted on M x , M 2 . One branch from the protoxylem of M L goes to meet the nearest plumular trace ; the other forms part of the group px 2 at the top of the section. The protoxylem of M 2 divides in the same way. x 200. Fig. 4. From same series, -18 mm. below Fig. 3. Insertion of plumular traces is completed. The xylem group of M L and M 2 are each crescent-shaped. The protoxylem of each crescent covers its convex outline : the concavity is occupied by a compact phloem group, x 133. Fig. 5. From same series, -03 mm. below Fig. 4. Protoxylem crescents broken into two groups, px 2 ,px 3 . The structure is that of a diarch root with two thin plates of protoxylem extended tangentially, x 133. Fig. 6. From same series, *15 mm. below Fig. 5. Phloem in four groups: protoxylem breaking up into four too. Tetrarch root-stele indicated, x 133. PLATE IV. Chlorogalum pomeridianum. Fig. 1. Outline of seedling A/, preserved in spirit, x 1 / 1 . (E. N. T.) Fig. 2. From microtome series through seedling A 3 ', just above first node. Double cotyledonary trace M x + M 2 with three protoxylem groups, px X) px 2 ,px 3 . Single plumular trace, which divides as it approaches cotyledonary trace into two branches, Pl x , Pl 2 . x 250. (E. S.) Fig. 3. From same series, .02 mm. below Fig. 2. Phloem masses above and below xylem. Four protoxylem groups, of which px / is plumular. Diarch root- stele is suggested, x 250. Fig. 4. From same series, .10 mm. below Fig. 3. Tetrarch root-stele, x 250. founded on the S trice hire of their Seedlings. 91 Anthericum Liliago . Fig. 5. Outline of seedling B L , preserved in spirit, x Vi- C E - s 0 Fig. 6. From microtome series through seedling B x , just above first node. The section cuts each plumular trace twice : in situ within the first leaf (A, B, C), and also as they approach the double trace of the cotyledon in two groups (Pl lt PIP). X 190. Fig. 7. From same series, -14 mm. below Fig. 6. The phloem is in two masses, but there are four distinct groups of protoxylem, px L , px^, px s , px{. X 190. Arthropodium cirrhatum. Fig. 8. Outline of seedling B x , preserved in spirit, x 1 / 1 . (E. S.) Fig. 9. From microtome series through seedling B t , above first node. The double trace from the cotyledon is moving towards the plumular traces PL x 250. Fig. 10. From same series, «i8 mm. below Fig. 9. The whole stele has been somewhat twisted in its descent. But it is clear from intermediate sections that px x represents the cotyledonary and px x the plumular protoxylem. The stele is root-like and diarch, but at + , + , are two small protoxylem groups in course of extinction, x 250. PLATE V. Allium neapolitanum. Fig. 1. From microtome series through seedling A x . Transverse section of embryonic stem-bud enclosed within enlarged base of cotyledon. Double bundle in cotyledon : three strands in first leaf, x 75. Fig. 2. From same section as Fig. 1. Double bundle of cotyledon enlarged, x 200. Fig. 3. From same series, .27 mm. below Fig. r, through first node. The phloem of the slender plumular trace has divided, and one branch fuses with each of the two cotyledonary phloem groups, x 200. Fig. 4. From same series, .04 mm. below Fig. 3. Diarch root-stele, x 75. Fig. 5. From same section as Fig. 4. Stele enlarged, x 200. Zygadenus elegans. Fig. 6. Outline of seedling A 3 , drawn from life, x Vi* (E. S.) Fig. 7. Transverse hand-section through petiole of cotyledon, showing single bundle, x 75. Fig. 8. From same section as Fig. 7. Bundle enlarged, x 200. Fig. 9. From microtome series through seedling A 3 . Transverse section of young stem-bud enclosed within enlarged base of cotyledon. Single bundle in cotyledon : three strands in first leaf, x 75. Fig. 10. From same section as Fig. 9. Bundle enlarged. Fig. 11. From same series, «i8 mm. below Fig. 9, through first node. A single plumular trace meets that from the cotyledon : both open out as they approach each other, and the phloem groups unite in pairs, x 200. Fig. 12. From same series, *07 mm. below Fig. 11. Diarch root-stele indicated, but not yet formed. The upper protoxylem group is derived from the cotyledon ; the lower from the plumular trace, x 200. 92 Sargant . — Theory of the Origin of Monocoty r edons. PLATE VI. Eranthis hie?nalis. Fig. i. Outline of seedling A 6y drawn from life, x %. (E. S.) Fig. 2. From microtome series through seedling A 2 . Transverse section of. embryonic stem-bud enclosed within base of cotyledonary tube, x 113. Fig. 3. From same series, *09 mm. below Fig. 2, passing through top of tuber. Each trace from the cotyledon, C l} C 2 , shows double structure, x 113. Fig. 4. From same series, *io mm. below Fig. 3. The two pairs of bundles are drawn side by side ; the xylem of each is in three groups, x 113. Fig. 5. From same series, -07 mm. below Fig. 4. Four phloem and eight xylem groups, x 113. Fig. 6. From same series, *73 mm. below Fig. 5, approaching the base of the tuber. The scattered traces have gathered together, and now form two phloem and four xylem groups. Three of the latter are complete : the fourth is forming to the SW. of the section, x 113. PLATE VII. Eranthis hiemalis. Fig. 1. From same series as Fig. 6 on Plate VI, and -27 mm. below it. Between each of the two phloem groups and the xylem internal to it, there are a few unlignified secondary elements in a radial row. px ' , px' y are the two groups of protoxylem within the phloem groups, which will disappear lower down, x 200. Fig. 2. From same series, *15 mm. below Fig. 1, through top of primary root. Diarch root-stele ; the groups px' y px’ , have disappeared, x 200. Fig. 3. From microtome series through older seedling A 5 . The section passes through the base of the tuber. Tetrarch xylem-plate. The elements px ' , px? are primary, x 200. Ranunculus Ficaria. Fig. 4. Outline of seedling A 3 , drawn from life, x %. (E. S.) Fig* 5 * Outlines of the cotyledons from three seedlings, A 3 , A iy B lt showing the venation of the blade, x 2. (E. S.) Fig. 6. From microtome series through seedling A 3 , cutting axis near insertion of first cauline root. The slender plumular trace in the upper part of the section is approaching the larger trace from the cotyledon in the lower part, x 100. Fig. 7. From same series, .09 mm. below Fig. 6, cutting axis at first node. The trace from the cotyledon is cut longitudinally as it approaches the plumular trace. Its double structure is clear, and the plumular trace is branching in two directions to meet it. x 2 50. Fig. 8. From same series, only *03 mm. below Fig. 7. The diarch root-stele is almost complete. The lower protoxylem group is from the cotyledon ; the upper one from the plumule, x 250. c Annals of Botany 1 4 P X .4 Albuca Nelsopi, Fi^s.l — 4. E. S arrant, del. SARGANT. ON 0 R I ' VoLXV/f, PL I. OF MONOCOTYLEDONS. University Press, Oxford. P X 3 + P X 3 + Hyacinbhus romanus, Figs. 5~9. W% I p*3 'Annals of Botany Vol.Xm, PL I P x < Albuca Nelsopi, Fi£s.l — 4. Hyacinthus romanus, Figs. 5-9. E. S argant, del. SARGANT. ON ORIGIfH OF MONOCOTYLEDONS. University Press, Oxford- (LSfrinaZs of folconi/ Musean atlanticum, Figs.l — 3. Muscari armenaicum, Figs. 4 — 9. E . Sargant , dsl . SAR6ANT ON ORIGIN Vol.XVflPl.il. P' X S I ■ ' University Press, Oxford : MONOCOTYLEDONS. M.xvn.pui. cyfanals 1 o/' jBotany E. Sargant, del. SARGANT ON ORIGIN OF MONOCOTYLEDONS. University Press, Oxford cu V ^yfnnalrS of Botany VoLXVlLPl/Il iperialis . F MONOCOTYLEDONS University Press, Oxford. Annals of Bo teeny Vol.. XVII. PI III. A Fritillari. SARGANT. ON ORIGIN 'mperialis. 0F MONOCOTYLEDONS. Oxford. c yfnnals of Botany HP Chloro^alum pom eridianum, Figs. 1—4. A. Robertson, del. SAR6ANT— ON 0 R I G ! Vol.XVILPlIV Arthropodium cirrhatum, Figs. 8~ 10. MON OCOTYLE DONS. University Press, Oxfofd. t-J/zinals of Botany Voimipuv Chlorogalum pomeridianum, Figs. 1— 4. Arbhropodium cirrhatum. Figs. 8-10. A. Robertson, del. University Press, Oxford. SARGANT— ON ORIGIN OF MONOCOTYLEDONS. Allium neapotitanum, Fi£s. 1~ 5. A . Robertson, del • SARGANT. — ON ORK N y \ /m t Vol.IVJl PI. V. Zygadenus elegans. Figs. 6-12. University Pr ess , Oxford. F monocotyledons. S. ery- throdonti In 5 . erythrodontus the male flower is seated on the stem close below the perichaetium (see Fig. 17). Now, in vS. setiferus there constantly occurs on the stem, just below the perichaetium, an innovation bud (see Fig. 42), and I think it is just possible that this bud, when very young, may have been mistaken for a male flower. If, as I feel convinced we must dp, we regard 5 . Lindigii (S. setiferus , Mitt.) as really dioicous, then the only important difference alleged between this species and 5 . latifolius is the presence of a ‘limbus angustus ’ in the leaves of the latter plant. An examination of the type specimens of 5 . latifolius in Mitten’s herbarium shows that the marginal cells in the lower half of the leaf are sometimes slightly different from those of the rest of the leaf. These marginal cells have their walls unthickened, and differ only from the adjacent leaf-cells in being slightly longer (Fig. 53); at about the middle of the leaf they cease. Whether or not it is considered that these marginal cells are sufficiently distinctly marked off to constitute a ‘ limb ’ — and in my opinion they are not — they are certainly to be found also in the leaves of vS. Lindigii (S. setiferus , Mitt.). Fig. 54 is drawn from the type specimen of setiferus in Mitten’s 136 Salmon. — A Monograph of herbarium. As regards the length of the excurrent nerve and the shape of the perichaetial leaves, I can find no differ- ence between Lindigii and ^S. latifolius. It may be noted that vS. Lindigii varies in size and also somewhat in habit; the stems are sometimes only a centimetre high, almost or quite simple, and of a rigid habit ; at other times, as is well seen in £ setiferusl the stems are more flaccid, much branched, and up to 4 cent. high. The most important characters, however, viz. the shape of the leaf, the strongly revolute margins, the characteristic areolation of hexagonal cells with pitted walls, the peristome with its long tube whitish at the base and divided above into sixteen nearly straight teeth each of which is split in its lower third into two filiform divisions, are found invariably in all the specimens, and I feel convinced that 5 . Lindigii , S. latifolius, and A. setiferus are names that have been given to one and the same well-marked species. The male plant does not seem to have been collected except in the case of the plant named 5 . latifolius in Mitten’s herbarium. The long arista, formed of the excurrent nerve, of the upper stem-leaves and perichaetial leaves is seen under a high magnification to be very minutely denticulate at intervals with subhyaline projections. The calyptra is truly mitrae- form, and is minutely asperous only towards the apex, and not anywhere setulose-hispid as is the calyptra of 6'. erythro- dontus and vS. clavipes. The stem in transverse section shows one or two peripheral rows of thick-walled cells, and is else- where composed uniformly of rather large polygonal cells with very thin and delicate walls, usually slightly and minutely thickened at the angles ; there is no ‘ central-strand/ The nerve shows in transverse section two ‘ pointer-cells ’ on the ventral surface, and on the strongly convex and projecting dorsal surface a well-developed band of stereid-cells ; there is a complete absence of * companion-cells.’ The superficial stomata at the extreme base of the capsule are few and scattered, with the long axis of the guard-cells sometimes parallel to that of the capsule, at others at right angles to it. 137 the Genus Streptopogon . The peristome of 5 . Lindigii has a very interesting and characteristic structure, not found elsewhere in the genus. It may be noted here that Muller and many authors describe the peristome- teeth of Barbala (including Syntrichid) as thirty- two in number, while Schimper, although giving this number in the c Bryologia Europaea,’ describes them in the £ Synopsis * as being sixteen in number, ‘ in crura 32 divisi.’ Brotherus also, in giving the characters of the family Pottiaceae , in which the genus Streptopogon is placed, says : * Zahne 16, einer niedrigen oder hoheren, zuweilen rohrenformigen, schrag gewiirfelten Basilarmembran aufsitzend, entweder flach, unge- teilt, durch enge Spalten durchbrochen, oft bis zur Basis in 2 (3) lineare und paarweise genaherte, meist ungleiche Schenkel geteilt, oder die Basilarmembran in 32 gleichweit gestellte, fast stielrunde, fadenformige, aufrechte oder schrage, allermeist spiralig links gedrehte Peristomaste gespalten, die sich nach der Anlage auf 16 P.-zahne zuriickfuhren lassen/ The peristome of 3 . Lindigii is certainly, I think, to be regarded as being composed of sixteen filiform teeth, each of which is regularly split into two filiform divisions in its lower third, rather than of thirty-two teeth uniting above into sixteen. It affords a very interesting example of a transitional stage. As in 3 . erythrodontus , there is at the mouth of the capsule a * false annulus,’ formed of a few rows of exothecial cells which suddenly become smaller and thicker-walled. It is worthy of note that the operculum on being removed from a nearly mature capsule frequently carries away with it, attached to its apex, the exserted part of the columella ; so that an approach is made towards those species, e. g. Pottia Heimii (Hedw.), Bry. eur., Desmatodon sy sty tins , Bry. eur., in which the columella is permanently and regularly attached to the operculum. S. cavifolius, Mitt. (Figs. 67-71). S. cavifolius , Mitt, in Spruce, Cat. Muse. Amazon, et And., 3 (1867) (nomen) ; Spruce, Muse. Amazon, et And., nr. 140 ; Mitt., Muse, austr.- amer., 180 (1869); Jaeger, Adumbr., i, 255 (1873); Paris, Index bryolog. in Actes Soc. Linn. Bordeaux, li, 275 (1897) ; C. Mull., Gen. 138 Salmon. — A Monograph of Muse. Frond., 421, 422, 423 (sect . Eustreptopogori) ( ‘ 1901,’ i. e. 1900) ; Broth, in Engler and PrantFs Nattirl. Pflanzenfam., 214. Lief., p. 418 (sect. Calymperella ) (1902). Dioicus?, laxe caespitosus, olivaceo-fuscescens, caule ad 2*5 cent, alto dichotome vel fastigiatim ramoso inferne radiculis fuscis ramosis dense vestito, foliis caulinis confertis patentibus vel raro erectis sicci- tate incurvis late ovato-oblongis concavis vel cymbiformi-concavis apice perfecte cucullatis 2-3 mill, longis margine utroque ad folii medium recurvo superne erecto undique integerrimo, nervo medio- cri flavo infra folii summum apicem desinente, cellulis mediis hexagonis et hexagono-rectangularibus marginem versus gradatim minoribus hexagono-quadratis superioribus regulariter hexagonis ad marginem quadratis inferioribus longioribus rectangularibus marginem versus subquadratis cellulis omnibus pellucidis utriculo primordiali collapso repletis aetate parietibus plus minus porosis, cellulis summis subtus (rarissime etiam supra) grosse papillatis, papillis apice truncatis gemmas anguste cylindricas transverse septatas e cellulis 4-8 compo- sitas ad 200 /x longas circ. 20 jx latas ferentibus, caeteris laevibus, inter- dum cellulis marginalibus 1-2-seriatis infra folii medium elongatis et limbum plus minus distinctum efformantibus, foliis perichaetialibus caulinis conformibus, sed parum maioribus e basi ampliori magis vaginante, apice cucullatis interdum gemmiferis, capsula in pedunculo perbrevi erecto crasso superne tumido-incrassato 1-5 mill, longo emergente erecta subcylindrica circa 2-5 mill, longa, peristomii immaturi dentibus filiformibus rubris fere ad operculi apicem pro- duces basi in tubum pallidum coalitis, operculo conico-subulato 1*25 mill, longo cellulis haud spiraliter contortis, calyptra mitraeformi glabra basi subinflata 1-75 mill, longa apice fusca cellulis basin versus laxis brevibus. Hab. — America australis : Ecuador , Andes Quitenses, Bafios ad pedem montis Tunguragua, in ramulis praecipue malvacearum suffruticosarum, etiam in monte Guayrapata (6,000-10,000 ped.) (Spruce, Musci Amazon, et And., nr. 140), sterilis ! Colombia ; Bogota, Pacho, 2,000 mtr. inter Fabroniam polycarpam et S. rigidum (leg. A. Lindig) in Herb. Hampe, sterilis ! America septentrionalis : Mexico ; inter Hypna , ad arbor, (in Herb. Ph. Bruch), c. fr. ! In Mitten’s description of the present plant no mention the Genus Streptopogon. 139 is made of the papillate gemmiferous cells at the apex of the leaves ; these, however, are found constantly in all the leaves, and are very characteristic of the species. The papillate cells at the back of the leaf are confined to the apical region, where they occur at the back of the hooded (cucullate) apex, not reaching quite to the incurved apical margin of the leaf and running down the leaf for a short way in two bands at a little distance from the nerve. The papillae are large, and very truncate at the apex. The gemmae are brownish, more or less cylindrical in shape, and consist of about 3-8 cells, the walls being apparently always transverse only and not longitudinal as well as in S'. rigidus. Very rarely a few cells on the upper (ventral) surface of the leaf, situated immediately below the incurved apex, bear the same shaped papillae, as well as those on the dorsal surface. I have observed this in the case of two leaves only amongst a considerable number of stems examined in Mitten’s herbarium and at Kew; also in a single leaf on one of the stems in Hampe’s herbarium, and here it was seen that the papillae bear gemmae of the same shape as those arising from the dorsal papilliferous cells. There occur also at times on the upper surface of the leaf long narrowly cylindrical gemmae, brownish in colour in the upper part and often pale below, 20 cells or more long, and sometimes slightly branched. These are somewhat similar to the gemmae which occur on the leaves of Ortho trichum Lyellii , Hook, and Tayl. Up to the present, S'. cavifolius has been known only, in the barren state, from the Andes of Quito (Spruce, Muse. Amazon, et And., nr. 140). There is, however, in Bruch’s herbarium at Kew a plant labelled ‘ Acrocarpum (nov. gen.) Capsida breviseta ( gymnostomo ?) Calyptra mitraeformis lacini - ata ; fol. late-lanceolata concavo-cucidlata. — Mexico, inter Hypna , ad arbor.’ On the label has been written later ‘ Streptopogon' \ and the plant proves on examination to be a fruiting example of S', cavifolius . This specimen bears a few very old and decayed capsules, also one young capsule with an apparently mature calyptra and a riper, nearly mature, 140 Salmon . — A Monograph of operculate capsule (Fig. 70). The calyptra is glabrous, and if, as appears to be the case, it is really mature forms in this character a notable exception in the genus, as in all the other species the calyptra is rough. In the nearly mature operculate capsule the peristome can be seen quite clearly through the cells of the operculum ; the teeth are red, almost straight, and spring from a palish basal membrane. The capsule is emergent, and is borne on a very short seta which is thickened upwards like that of 5 . Lindigii ; the perichaetial leaves resemble the cauline, except that they are slightly longer, and have the lower part more sheathing. In the single fertile stem that I have dissected, I was unable to find any male inflorescence ; as, however, the capsule was very old and the stem-leaves decayed, and as in the present genus the male flower in the autoicous species is very small and easily passed over, too much value must not be attached to this negative evidence, since it is possible that the antheridia may have decayed away. I have also detected four barren stems of .S', cavifolius growing intermixed with the type-specimens of 4 Calymperes Lindigii ’ (S. rigidus) in Hampe’s herbarium at the British Museum, so that a third locality, viz. Colombia, Bogota, Pacho, 2,200 mtr., can be now added for the species. The Mexican record noted above is of great interest, not only as adding the species to the Flora of North America, but especially by the discovery of the fruit, as establishing the position of the species in the present genus ; previously, on account of its barren condition and anomalous shaped leaves, its affinity was somewhat doubtful. In its usual form S. cavifolius has rather broad patent leaves, about \ mill, wide, slightly concave throughout up to the hood-shaped (cucullate) apex. Sometimes, however, as is well seen in stems in Mitten’s herbarium, the leaves are narrower, erect, not patent, and cymbiform-concave up to the cucullate apex (Fig. 63). The apex of the leaf in the latter case is often slightly wider than the lower part of the leaf, owing to the margins there being strongly incurved, so that the Genus Streptopogon . 14 1 the leaf, especially in the dry state, has a distinctly spathulate outline. That this form is not separable systematically, is clearly shown by the fact that on the stems in question leaves of the more usual form, i. e. wider and less concave, occur lower down the stem, especially at the places where branching takes place. I have also seen on other stems, e. g. in the specimens in Spruce, 4 Muse. Amazon, et And., nr. 140 ’ (in Herb. Kew), leaves clearly intermediate in shape between these two extremes. The stem seen in transverse section is composed of one or two peripheral rows of thick-walled cells enclosing a tissue formed of rather large cells with very thin and often flexuose walls ; there is no 4 central-strand ’ differentiated. The leaf- nerve is composed of two ‘ pointer-cells ’ and a strongly convex dorsal band of stereid-cells ; 4 companion-cells ’ are absent (see Fig. 68). I have followed Brotherus ( 3 ) in placing the present species in the section Calymperella of the genus. In order to do this a slight emendation of the characters of that section becomes necessary (see above, p. 114). Muller (21 and 24 ) defined his sections as follows : 4 Calymperella, C. Mull. Blatter mit anomaler, aus der vorgeschobenen, halsartig verlangerten Rippe gebildeten Blattspitze, welche sich in Puccinia-artige Korper auflost 1 ; and 4 Eustreptopogon, C. Mull. Blatter mit normaler Spitze ; Rippe auslaufend, oder in eine mehr oder weniger lange Granne austretend.’ Muller, probably without seeing specimens, placed the present species in the sect. Eustreptopogon, but it seems clear that its proper position is in Calymperella with 5 . rigidus, to which species it shows affinity in leaf-areolation and in the production of gemmae. S, clavipes, Spruce (Figs. 28-37, 7 2 j 73)- S. erythrodontus (Tayl.), Wils., var. clavipes, Spruce, Cat. Muse. Amazon, et And. 3 (nomen) (1867). A. clavipes, Spruce ex Mitt., Muse, austr.-amer., 178 (1869) ; Jaeger, Adumbr. i, 255 (1873) ; Paris, Index bryolog. in Actes Soc. Linn. Bordeaux, li, 275 (1897) ; C. Mull., Gen. Muse. Frond., 421, 423 142 Salmon . — A Monograph of (sect. Eustreptopogon) (‘ 1901/ i.e. 1900) ; Broth, in Engler and Prantl’s Natiirl. Pflanzenfam., 214. Lief., p. 418 (sect. Eustreptopogon ) (1902). S. Afasseei, Mitt. mss. in Herb. Dioicus, fasciculato-caespitans, olivaceo-fuscescens, habitu orthotri- choideo ; caule circ. 3 cent, alto ob innovationes fertiles plus minus dichotome ramoso, foliis caulinis flaccidis laxe confertis interdum subbiseriatis siccitate torquescentibus e basi ovali suberecta amplexante ad angulos decurrente in laminam elongato-lanceolatam flexuosam interdum semitorquatam patulo-patentem nervo excurrente plus minus longe aristatam productis, ad apicem limbatis, margine utroque ad folii medium vel paullulo ultra revoluto superne erecto denticulato vel spinoso-denticulato, cellulis superioribus plus minus regulariter hexa- gonis circ. 60 x 16-18 /x utriculo primordiali contracto repletis inferio- ribus longioribus oblongis vel subrectangularibus pellucidis marginalibus 1-4 seriatis elongatis angustis parietibus incrassatis limbum flavum unistratosum efformantibus, nervo mediocri luteo-rufescente in aristam validam flexuosam laevem producto, foliis superioribus perichaetiali- busque maioribus ad 7 mill, longis 1-50 mill, latis interdum erecto- patentibus et apice plus minus recurvis, foliis perichaetialibus caulinis superioribus conformibus apicibus capsulam superantibus, fructu ex eodem perichaetio interdum binato saepe innovatione continua ad latus deiecta, capsula in pedunculo ea tertia parte breviore superne incrassato tumido immersa vel emergente erecta oblongo-cylindrica circ. 3 mill, longa 1 mill, lata olivacea exannulata ore rubro crenulato exothecii cellulis rotundato-quadratis vel breviter rectangularibus collen- chymaticis ad capsulae os subito minoribus parietibus longitudinalibus valde incrassatis, basi ima stomatibus numerosis superficialibus in- struct^ peristomio rubro circ. 1*5 mill, longo brevissime tubuloso tubo haud rectangulari-tessellato, exinde cruribus 32 filiformibus liberis minute papillosis inaequilongis siccitate sinistrorsum contortis humidi- tate rectis vel apice divergentibus, columella exserta, operculo conico- subulato 1-75 mill, longo apicem versus tenui interdum subflexuoso cellulis haud spiraliter contortis basi margine rubro crenulato, calyptra paullulum infra os capsulae descendente mitraeformi superne fuscata glabra inferne usque ad basin valde setuloso-hispido, sporis globosis laevibus 23-30 n diam. Planta mascula feminea minore circ. 1 cent, alta ramulis brevibus infra florem gemmiformem crassius- culum oriundis repetite dichotomo-ramosa, caule radiculoso, foliis perigonialibus late ovatis concavis elimbatis nervo excedente breviter the Genus Streptopogon. 143 cuspidato-aristatis, paraphysibus filiformibus articulis superioribus subinflatis antheridia superantibus. Hah. — America australis. Ecuador — Andes Quitenses: Palla- tanga, 6,000 ped., c. fr. (Spruce, nr. 141 d) ! ; Loxa (Loja), on branches, c. fr. et pi. masc. (G. Massee, 1870), nr. 14 (sub S. Massed \ Mitt. mss. in Herb. Mitt.) ! The present species was first published by Spruce ( 29 ) in 1867 as a variety of A. erythrodontus (Wils.), but was after- wards given specific rank in Mitten’s ‘ Musci austro-americani ’ in 1 869. The only locality hitherto recorded for the plant has been Pallatanga in the Andes of Quito, where it was origin- ally discovered by Spruce, and distributed by him under the number 141 d (not 1418 as is given in ‘Muse, austr.-amer.’) in his ‘ Musci Amazonici et Andini.’ Although A. clavipes is very similar in habit and vegetative characters to S', ery- throdontus ^ a close comparison of the two species shows the existence of several important differences. In the first place the capsule of S', clavipes is immersed or emergent, never exserted as in S. erythrodontus ; the membrane of the tubular base of the peristome is not ‘ tessellated,’ and the free teeth of the peristome are not at all twisted in the moist state, and in the dry state less so than those of S. erythrodontus ; the exothecial cells are collenchymatous ; the cells of the operculum are not spirally arranged, but form straight rows ; and the calyptra is setulose from about the middle to the extreme base, the hairs being longer than those of A. erythro- dontus. In vegetative characters there is much less difference between the two species ; the shape of the leaf is the same, but the upper areolation of A. clavipes as a rule differs in the cells being narrower and more regularly hexagonal, — the cells often being arranged in a seriate manner (Fig. 36). It is to be noted, however, that occasionally the cells are quite irregu- larly arranged, and of the same shape as those of .S', erythro- dontus (Fig. 73). The limb is 3-4 cells wide in the lower part of the leaf, and, in all the specimens I have examined, is continued to the extreme apex, although becoming in the upper part of the leaf very narrow and reduced to one or two 144 Salmon.— A Monograph of cells wide. The leaves in drying shrink very much, and become slightly twisted, keeping erecto-patent and not be- coming appressed. The present species is described as ‘ monoicous ’ in ‘ Muse, austr.-amer./ but no description of the male inflorescence is given. On dissecting several fertile stems of the examples in s Muse. Amazon, et And., nr. 141 d,’ no trace of any male inflorescence could be found. Further, a specimen in Mitten’s herbarium shows that clavipes is really dioicous. This specimen bears the name of ‘ 5 . Masseei’ and is thus described in manuscript: ‘Folia oblongo-ovalia patentia apice recurva acuminata nervo in acumen piliferum apice laeve exeunte margine recurva inferne reflexa apicem versus denticulis aculeiformibus e limbo cellularum angus- tissimarum seriebus 2-3 oriundis serrulata, cellulis in folii medio oblongis versus marginem abbreviatis subquadratis utriculo collapso [repletis] perichaetialia parum longiora ad thecae cylindraceae apicem vel paulo infra attingentia, pedunculus brevissimus in collem thecae sensim dilatatus operculum elongato-conicum, peristomium basi coalitum. — Loxa, on branches ; Massee to Spruce. Very like -V. setiferus , but with a distinct limb ; the capsule with scarcely any distinct seta which is not twisted.’ This moss is certainly 5 . clavipes , agreeing exactly with the examples in Spruce's ‘ Muse. Amazon, et And., nr. 141 d.' The specimen is of special interest from the fact that it bears male flowers. These are borne on what appears to be a dis- tinct plant, the stem of which arises out of the tomentum by the side of a fertile plant. The stem of the male plant is 1 centimetre high, and is branched dichotomously at half its height beneath a male inflorescence ; each branch bears a male inflorescence at its apex, beneath which the dichoto- mous branching is repeated. The stem at the places where the branches originate produces numerous brown radicles. In general habit, and in the rather thick gemmiform flowers, the male plant of S. clavipes much resembles that of S. lati- folius , Mitt. (S. Lindigii , , Hpe). In the single stem that 145 the Genus Streptopogon. occurs in Mitten’s herbarium the leaves are much damaged, especially at the apex and margins, by parasitic algae, &c., or are very old and decayed, so that only traces of the limb are here and there to be seen, while the marginal teeth have apparently been destroyed by erosion. The perigonial bracts are quite elimbate. The structure of the stem and of the leaf-nerve of clavipes is the same as that found in ery thro don tus. The stomata at the base of the capsule are rather numerous ; the long axis of the guard-cells is sometimes parallel to that of the capsule, at others at right angles to it. On the whole, 5. clavipes must be considered to differ specifically from .S. erythrodontus in its immersed or emergent capsule, wdth collenchymatous exothecial cells, in the less twisted peristome, in the cells of the operculum not being spirally arranged, the setulose base of the calyptra with longer hairs, the (usually) narrower and more regularly hexagonal cells in the upper part of the leaf, and in the inflorescence. The difference shown in the cellular structure of the oper- culum by two such closely allied species as S. erythrodontus and .S. clavipes is interesting as affording evidence that no generic importance can be attached to the spiral or straight arrangement of the cells of the operculum (cf. Muller (24), pp. 30, 406). L 146 Salmon. — A Monograph of Bibliography. 1. Bescherelle, E. : Florule bryologique de Mayotte. Ann. Sci. Nat., 7 e s6r., ii, 88 (1885). 2. Idem : Essai sur le genre Calymperes. Loc. cit., 8 e sdr., i, 290 (1895). 8. Brotherus, V. F. : in Engler and Prantl’s Natiirl. Pflanzenfam., 214. Lief., 4 r 3> 4 I 7 _ 4 I 9> Fi gs. 271, 272 (1902). 4. Brown, R. : New Zealand Musci : Notes on the genus Streptopogon, Wils., with description of a new species. Trans. New Zealand Instit., xxx, 409, 410, PI. XLI, Fig. 2 (1897). 5 . Hampe, E. : Prodromus Florae Novo-Granatensis. Ann. Sci. Nat., 5® ser., iii, 342, 350, 35i (1865). 6. Idem: Musci novi Musei Melbournei. Linnaea, xl, 304 (1876). 7. Hooker, J. D. : Handbook of the New Zealand Flora, 420 (1867). 8. Idem et Wilson, W. : Musci Antarctica Hooker’s Lond. Journ. of Bot., iii, 539 (1844). 9. Idem et Idem : in Hooker’s FI. Antarctica, ii, 399, Tab. cli, Fig. 6 (1847). 10. Jaeger, A. : Adumbratio Florae Muscorum, i, 254, 255, 327 (1873), ii, 670 (1879). 11. Mitten, W. : Catalogue of Cryptogamic Plants collected by Prof. W. Jameson in the vicinity of Quito. Hooker’s Journ. of Bot., iii, 51 (1851). 12. Idem : Description of some new species of Musci from New Zealand, &c. Journ. Linn. Soc. London, iv, 72 (1859). 12*. Idem : In Hookers Flora Tasmaniae, ii, 376 (i860). 13. Idem : On the Musci and Hepaticae from the Gamer oons Mountain and from the River Niger. Loc. cit., vii, 147 (1864). 14 . Idem: Musci austro-americani. Loc. cit., xii, 14, 127, 177-180 (1869). 15. Idem : The Musci and Hepaticae, collected by H. N. Moseley, M.A., Naturalist to H.M.S. ‘Challenger.’ Loc. cit., xv, 66 (1876). 16. Idem : Botany of Kerguelen Island : Musci. Phil. Trans. Roy. Soc. Lond., clxviii, 32-34 (1879). 17. Idem : in Report on the Scientific Results of the Voyage of H.M.S. ‘ Chal- lenger.’ (Botany), i, pt. 2, 223 (1885). 18. Muller, C. : Synopsis Muscorum Frondosorum, i, 606 (1849), ii, 630 (1851). 19 . Idem : Reliquiae Rutenbergianae, iii. Abhandl. d. naturwiss. Vereins Bremen, vii, 207-208, Taf. xiii A and B (1882). 20. Idem: Bryologia Austro-Georgiae, in Die intemat. Polarforsch., 1882-1883; Die Deutsche Expedition, ii, 311-313 (1890). 21 . Idem: in Brotherus, Musci Schenckiani. Hedwigia, xxxiii, 128 (1894). 22. Idem : Bryologia Hawaiica. Flora, Ixxxii, 439 (1896). 23. Idem : Prodr. Bryologiae Bolivianae. Nuov. Giom. Bot. Ital., n. s., iv, 49, 50 (1897). 24. Idem : Genera Muscorum Frondosorum, 420-424, 458 (‘ 1901,’ i.e. 1900). 25. Paris, E. G. : Index bryologicus. Actes Soc. Linn. Bordeaux, li, 275-277 ( i8 97 )« 26 . Idem : Index bryologicus, Suppl., i, 86, 313 (1900). the Genus Streptopogon . 147 27. Salmon, E. S. : Bryological Notes. Journ. of Bot., xxxix, 357-359, tab. 427(1901). 28. Schwaegr ICHEN, F. : Species Muscorum Frondosorum, tab. cccx b (1842). 29. Spruce, R. : Catalogus Muscorum fere omnium quos in terris amazonicis et andinis per annos 1849-1860 legit Ricardus Spruceus, 3 (London) (1867). 30. Sullivant, W. S. : Musci. U. S. Expl. Exped. under the gommand of Charles Wilkes, U. S. N., 5 (1859). 31. Taylor, T. : The distinctive characters of some new species of Musci collected by Prof. W. Jameson in the vicinity of Quito, &c. ; Hooker’s Lond. Journ. of Bot., v, 50 (1846). 32. Wilson, W. : Remarks on the new species of Musci from Quito and Swan River, indicated by Dr. Taylor. Hooker’s Lond. Journ. of Bot., v, 450, tab. xv, f (1846). 33. Idem : in Mitten’s Catalogue of Crypt ogamic Plants collected by Prof. W. Jameson in the vicinity of Quito. Hooker’s Journ. of Bot., iii, 51 (1851). 34. WRIGHT, C. H. : Mosses of Madagascar. Journ. of Bot., xxvi, 264 (1888). I. 2 148 Salmon . — A Monograph of EXPLANATION OF FIGURES IN PLATES VIII, IX and X. Illustrating Mr. Salmon’s Monograph of Streptopogon. PLATE VIII. Figs. 1-27. Streptopogon erythrodontus (Tayl.), Wils. — Fig. 1, portion of plant, natural size ; 1 a, two capsules (showing variation in shape), from two stems in the same tuft (Spruce, Muse. Amazon, et And., nr. 141 c , in Kew Herbarium) x 2 ; Fig. 2, stem-leaf, x 14; Fig. 3, apex of same, showing limb continued to apex, and non-median nerve, x 52 ; Fig. 4, areolation in upper half of same, midway between the nerve and the margin, at three-quarters the length of the leaf, x 255 ; Fig. 5, margin of another stem-leaf, at a little distance from apex of lamina, showing the spinose-denticulate marginal cells, and the limb gradually ceasing, X255 ; Fig. 6, margin of stem-leaf in the var. intermedins , var. nov., at a little distance below the apex of the lamina, showing the weak denticulation and complete absence of limb, x 255 (Spruce, Muse. Amazon, et And., nr. 141 b (in part), in Kew Herbarium) ; Fig. 7, basal cells of stem-leaf of S. erythrodontus , showing pitted walls, x 400 ; Fig. 8, mouth of capsule, showing peristome with its tubular base and the exserted columella (Spruce, Muse. Amazon, et And. , nr. 141, in Kew Herbarium), x 52; Fig. 9, four teeth of the peristome, and part of the ‘tessellated’ membrane of the basal tube, x 68; Fig. 10, areolae of the ‘tessellated’ membrane, from the example in Spruce, Muse. Amazon, et And., nr. 141, in Kew Herbarium, x 150; Fig. 11, exothecial cells at mouth of capsule, forming a ‘false annulus,’ x 255; Fig. 12, stoma at base of capsule, x 255; Fig. 13, mitraeform calyptra, x 25; Fig. 14, cucullate-mitraeform calyptra, x 12; Figs. 15, 16, hairs from the calyptra, x 255; Fig. 17, male inflorescence, seated on the stem below the perichaetium, x 25 ; Figs. 18, 19, perigonial leaves, x 25; Fig. 20, transverse section of stem, x 150; Fig. 21, transverse section in lower half of stem-leaf, x 52; Figs. 22, 23, transverse sections of nerve and margin of leaf, in lower half of leaf, x 255; Fig. 24, transverse section in upper half of stem-leaf, x 52 ; Fig. 25, transverse section of nerve and part of lamina of leaf, showing a bistratose row of cells in the lamina, x 255; Fig. 26, transverse section of nerve and part of lamina of another stem-leaf, showing the occurrence of mammillate cells, x 255; Fig. 27, transverse section of the margin in the upper half of leaf, x 255. (Unless otherwise stated, all figures are drawn from authentic specimens (coll. Jameson), in the Kew Herbarium.) Figs. 28-37. S. clavipes, Spruce; Fig. 28, capsule and perichaetial leaves, x 12; Fig. 29, mouth of capsule, showing peristome (in the wet state) with short tubular base (the membrane of which is not tessellated) and the exserted columella, x 52 ; Fig. 30, part of peristome, showing teeth and membrane of tubular base, x 68; Fig. 31, collenchymatous exothecial cells, x 400; Fig. 32, mitraeform calyptra, x 25, and hair from base of same, x 255; Fig. 33, oper- culum, x 14; Fig. 34, stem-leaf (somewhat flattened), x 12; Fig. 35, margin of same, at about one-fifth from the apex, x 255 ; Fig. 36, areolation in upper half 149 the Genus Streptopogon. of leaf, midway between the nerve and the margin, x 255 ; Fig. 37, two stomata at the base of the capsule, x 255. (All figures drawn from the specimens in Spruce, Muse. Amazon, et And., nr. 141 d, in the Kew Herbarium.) Fig. 38. Transverse section of stem-leaf of S. rigidus , Mitt., from the specimen in Spruce, Muse. Amazon, et And., nr. 139, in the Kew Herbarium, x 255. Fig* 39* Gemmae from apex of leaf of ‘ S. Calymperes, C. Mull.,’ from the type in Muller’s herbarium, x 150. Fig. 40. Gemmae from apex of leaf of S. rigidus , Mitt., from the specimen in Spruce, Muse. Amazon, et And., nr. 139, in the Kew Herbarium, x 150. PLATE IX. Figs. 41-61. S. Lindigii, Hampe; Fig. 41, plant, nat. size; Fig. 42, capsule and perichaetial leaves, showing an innovation bud below the perichaetium, x 13; also part of an arista, near its base, showing the minute denticulations, x 255; Figs. 43, 44, two capsules, x 13; Fig. 45, part of peristome, showing the basal membrane, and each tooth divided into two in its lower third, x 68 ; Fig. 46, mitraeform calyptra, with its scabrous apex, x 68 ; Fig. 47, papillae towards the apex of the calyptra, x 255 ; Figs. 48, 49, two stem-leaves, showing variation in shape, x 12; Fig. 50, apex of a stem-leaf, x 52; Fig. 51, margin of same, just below apex of lamina, x 255; Fig. 52, areolation in upper half of stem-leaf, x 255 ; Fig. 53, marginal cells in lower half of stem-leaf, from the type of ‘ S. latifolius , Mitt.’ in Mitten’s herbarium, x 255 ; Fig. 54, marginal cells towards the base of a stem-leaf, from the type of ‘ S. setiferus , Mitt.,* in Mitten’s herbarium, x 255 ; Fig. 55, transverse section of nerve in lower half of stem-leaf, x 255 ; Fig. 56, transverse section of margin in lower half of stem-leaf, x 255; Fig. 57, portion of male plant, nat. size ; Fig. 58, male flower, x 12 ; Fig. 59, perigonial leaf and antheridium, x 25 ; Fig. 60, exothecial cells and two stomata at base of capsule, x 255 ; Fig. 61, exothecial cells at mouth of capsule, forming a ‘false annulus,’ x 255. (All figures are drawn, unless otherwise stated, from the type in Hampe’s herbarium.) Figs. 62-71. S. cavifolius , Mitt.; Fig. 62, stem-leaf, x 25; Fig. 63, another stem-leaf, with incurved margins and subspathulate outline, x 15; Fig. 64, papillate gemmiferous cells borne by the leaf on the dorsal surface towards the apex, x 400; Fig. 65, side view of a papilla, showing the truncate apex, x 400; Fig. 66, a gemma, borne by the papillate cells, x 255; Fig. 67, margin and areolation in the upper half of a stem-leaf, x 255 ; Fig. 68, transverse .section of nerve towards base of stem-leaf, x 400 ; Fig. 69, transverse section of margin in lower half of stem-leaf, x 400 ; Fig. 70, capsule and perichaetial leaf (from the Mexican example in Bruch’s herbarium at Kew), x 12 ; Fig. 71, calyptra, slightly inflated at base, x 15. (Unless otherwise stated, all figures are drawn from the type in Mitten’s herbarium.) Figs. 72, 73. S. clavipes , Spruce; Fig. 72, mouth of capsule, showing peristome in the dry state, x 52 ; Fig. 73, areolation of a stem-leaf, at about one-third from the apex, showing the irregularly shaped polygonal cells, x 255 (from the specimen in Spruce’s Muse. Amazon, et And., nr. 141 d in the Kew Herbarium). Figs. 74-77. ‘ Calymperes Lindigii , Hampe,’ from the type in Hampe’s her- barium ; Figs. 74-76, stem-leaves; Fig. 74, a lower leaf; Figs. 75, 76, two upper leaves, x 12; Fig. 77, part of a gemma, showing germination, x 255. 150 Salmon. — A Monograph of the Genus Streptopogon. Figs. 78, 79. S. rigidus , Mitt., areolation of upper part of two leaves from the same stem, showing (78) subhexagonal or (79) subrectangular cells, x 255 (from specimens collected by Weir at Boqueron, Bogota, in Mitten’s herbarium). Figs. 80, 81. Two gemmae, one germinating, from an authentic specimen (ex herb. Brotherus) of ‘6*. Schenckii, C. Mull.,’ in the Kew Herbarium, x 150. PLATE X. Figs. 82-88. ‘ S. Schenckii , C. Mull.’; Fig. 82, plant in the wet state, nat. size; Fig. 83, plant, in the dry state, x 9 ; Fig. 84, one of the upper gemmiferous leaves, x 13; Fig. 85, apex of same, with all but five of the gemmae removed, x 52; Fig. 86, one of the lower stem-leaves, x 13; Fig. 87, areolation in the upper half of a stem-leaf, x 255. Fig. 88, areolation at margin of stem-leaf, at about one-third from the apex, x 255. (Figs. 82, 83, from an authentic specimen (ex herb. Brotherus) in the Kew Herbarium ; Figs. 84-88, from the type in Muller’s herbarium.) Fig. 89. Gemma from leaf of ‘ S. Calymperopsis , C. Milll.,’ showing point of attachment at apex of leaf, x 150 (from the type in Muller’s herbarium). Figs. 90-92. 1 Calymperes Lindigii, Hampe,’ from the type in Hampe’s her- barium; Fig. 90, one of the lower stem-leaves, x 17; Fig. 91, apex of one of the upper leaves, x 52 ; Fig. 92, a gemma, x 150. Fig. 93. Basal areolation of stem-leaf of S. rigidus , Mitt., showing group of hyaline cells next the nerve, x 68 (from the specimen in Spruce, Muse. Amazon, et And., nr. 139, in the Kew Herbarium). Fig. 94. Transverse section of the nerve in lower half of leaf of * Calymperes Lindigii, Hampe,’ from the type in Hampe’s herbarium, x 255. Figs. 95, 96. Germinating gemmae of .S’. rigidus , Mitt., occurring among the lower leaves of an example collected by Weir at Boqueron, Bogota, in Mitten’s herbarium. Fig. 95, x 68; Fig. 96, x 150. Fig. 97. Apex of a stem-leaf from ‘ S. Calymperes , C. Mull.,’ from the type in Muller’s herbarium, x 150. /£ * ) tstfrinaL s of ftodani/ £ . S . Salmon, del. SALMON — ON STREPTOPOGON Vol.XWlPl.V/i 7. University Press , Oxford. Vol.XVIlPl.VJI/. £.S Salmon, del. University Press. Oxford. SALMON — ON STREPTOPOGON iS/nnal'S of ' JBotany SALMON ON STR EPTOPOGON. VI XVII, Pi IX. University Press, Oxford. Urinal'S of Botany VolWIfPlIX. SALMON ON STREPTOPOGON. Jjnnctls of Botoony Vol.XVIlPl.I. SALMON ON STREPTOPOGON. Some recent Observations on the Biology of Roridula. BY R. MARLOTH, Ph.D., M.A. With a Figure in the Text. MONG the various plants which possess a special interest dTx. to the biologist there are hardly any of greater impor- tance than the insectivorous plants. Belonging to several widely different natural orders, they are spread over all five continents, occurring in the forests of the tropics as well as in the tundra of the arctic regions, in the marshes near the shore of the sea as well as on the cloud-capped summits of the mountains. South Africa possesses two genera of insectivorous plants, both belonging to the natural order Droseraceae, viz. Drosera and Roridula. While the European species of sundews are tiny plants with radical leaves and inconspicuous little white flowers, some of the South African species develop stalks nearly a foot high and bear large handsomely coloured flowers. Unique in its structure, however, is the other genus, viz. Roridula, for while all other Droseraceae are small herbs only, Roridula forms shrubs. There are two species only in exist- ence, no other shrubby Droseraceous plant being known. These two species are R. dentata , L. and R. Gorgonias PL, which differ in their leaves as well as in the size of the plants, l Annals of Botany, Vol. XVII. No. LXV. January, 1903.] 152 Mar loth. — Some recent Observations for while the latter is a shrublet from 12 to 15 inches high, which possesses entire leaves, the former grows to a height of 4 feet and bears dentate leaves. The leaves of both species are closely covered with glandular hairs, similar in structure to those of Drosera (Fig. 15, 1 and 5). That the secretion Fig. 15. 1. Flowering branch of Roridula dentcita, L. 2. Flower. 3. Stamen in its first stage. 4. Stamen in its second stage. 5. End of a twig of R. Gorgonias , PI. All natural size. of these hairs is most effective is proved by the large number of insects which are found on every shrub of the plant. This property of the plant is well known among the people of the districts where it grows, for sometimes they suspend branches of the shrub in their houses for the purpose of catching flies. In fact it is known to the country people as the fly-bush. When recently visiting one of the localities where R. dentata is known to grow, viz. the valley above the Tulbagh water- 1 53 on the Biology of Roridula. fall, I noticed a spider walking about on the bushes, and on examining the bushes more closely I found that the spiders were quite numerous. They were all of one kind, belonging to the genus Synaema 1 (Crab-spiders). Dr. Purcell, who kindly examined the specimens, is of the opinion that it is an un- described species. The crab-spiders spin no web, but wait for their prey and pounce upon it whenever it comes near enough. This species had selected the Roridula for its residence, and was evidently quite at home there, for numerous little nests were hidden among the leaves, some of which were empty and serving only as hiding-places for the spiders, while others contained a large number of young spiders. The surprising feature of the matter was, that the spiders were able to walk or run over the leaves without the slightest hindrance from the sticky secretion of the tentacles. When- ever an insect was caught by a leaf and began to hum or to struggle, a spider in its neighbourhood would dart from its nest and secure the prey. Hence it is evident that the spider must be protected by some kind of varnish or grease against the sticky fluid, for neither their legs nor their bodies adhere to it in the slightest degree. Whether the same species of spider lives on any other plant is not known, but it has evidently adapted itself to the Roridida , and lives on the insects caught by the bush. As the R. dentata grows also in the Cedarbergen and the Cold Bokkeveld I have endeavoured to obtain some fresh material from those regions, in order to ascertain whether the spider occurs there as well, but owing to the disturbed state of the country I have not been successful as yet. The other species of Roridula , viz. R. Gorgonias , was for a long time only known to occur on the mountains of the river Zonder Ende, but recently Dr. Stoneman had found it in the valley of the Steenbrass river. When I visited this locality last February, I found the greater part of the valley burnt out, but finally succeeded in discovering a small patch of the plant. There were no spiders or spiders’ nests on them, 1 Nature, vol. lviii, 1898, p. 275. 154 Mar loth. — Some recent Observations and whether such may occur at the other locality of the plant I am unable to say. While studying the structure of the flowers of the shrub (Fig. 15, 2), I noticed that the position of the anthers varied, for some anthers were appressed to the filament, i. e. they pointed downwards, while others formed the continuation of the filament, standing upright. I soon detected the cause of this difference of position, for, on irritating the connective of a stamen, I saw the anther swinging round with a jerk ejecting a little cloud of pollen. This showed that the stamens of Roridula are irritable (Fig. 15, 3 and 4). This special contrivance showed that the fertilization of these flowers must be effected by insects ; but in spite of my watching the shrubs for about an hour, I did not observe any visitor. The difficulty of the case was to understand how an insect could be adapted to visiting these flowers, for how could it escape being caught by the leaves or calyx-lobes, unless it had learnt to avoid the danger in some special way. At last I found the solution of the problem, for I noticed a small hemipterous insect walking about between the leaves. I succeeded in securing a few of these insects, which were evidently as proof against the sticky fluid as the spiders. They /were kindly identified by Dr. Purcell and Mr. Mally as a species of Capsids, apparently undescribed. The micro- scope showed me that these insects possess a proboscis somewhat similar to that of a mosquito, and that they con- sequently obtain their food by perforating the tissues of plants and sucking their juices. As I found young specimens of this hemipter two months afterwards on plants of Roridula which I had brought with me to Capetown, and which I was culti- vating in my garden, it is evident that the eggs had been deposited on the plants and that this insect lived on the juice of the young tissues of the Roridula. The question suggested itself, whether the flowers possessed any special attraction for this insect. On investigating the contents of the gland-like connectives of the stamens, I ascertained by micro-chemical reactions that the internal tissue of the connective contained i55 on the Biology of Roridula. sugar in its cells, while the cells of its epidermis were free from it. The connective is consequently not a nectary in the ordinary sense of the word ; that means to say, it does not secrete honey on its surface, but it offers it only to insects which obtain their food by piercing the tissues. As our Capsid is not only able to do that but also to walk about freely on the plant, as if there were no tentacles with sticky glands, it is obvious that this insect is specially adapted to the fertilization of the flowers of Roridula. In order to obtain, if possible, some evidence in favour of this view, I examined the few specimens of the insect which I possessed for pollen-grains. Two specimens which I ex- amined did not contain any, but the third one carried quite a number of grains of Roridula pollen between the hairs of its body. Taking all these facts into consideration, there can be no doubt with regard to the relation between this insect and the plant. As stated above, there were no spiders on the specimens of the other species which I found in the Steenbrass river valley, but I noticed at once that R. Gorgonias was also inhabited by a Capsid, which was evidently quite different from that on R. dentata. As on that occasion I had provided myself with a muslin bag I was able to secure a larger number of the insects. On examining the spirits of wine in which I had pre- served them, I found numerous pollen grains of Roridula, and as the structure of the stamens of this plant, especially that of its connectives, is quite similar to that of R. dentata , it is evident that this insect lives on R. Gorgonias in the same way as the other one on R. dentata. Summing up these observations, we find that the Roridula catches insects in order to obtain an additional food-supply, but that a spider robs the plant of a share of its prey in spite of the sticky tentacles. At the same time the Capsid takes some of the juice of the plant, having likewise acquired immunity from the dangers of the glandular hairs, but the plant utilizes this otherwise 156 Mar loth. — Some recent Observations unwelcome lodger by offering him some special tit-bits in its flowers, securing in this way, with the aid of some specially developed contrivances, the cross-fertilization of its flowers. It is hardly possible to imagine a more complicated relationship of plants and animals. There is another peculiarity of R. dentata which deserves special attention. All other Droseraceous plants occur in swampy or wet places, and the annuals are found in localities which are moist during certain seasons of the year. The locality, however, where I found R. dentata was the dry slope of a hill, which consisted of hard iron gravel and clay. No other hydrophilous plants were to be seen. The unusual nature of the locality induced me to dig up several plants and to take a sample of the soil from the lowest layer into which its roots had penetrated. I put the sample at once into a well- corked tube and analysed it later on. It contained only 174 per cent, of moisture (expelled at 120° C.), and the loss by ignition, which represents the combustible matter and the chemically bound water, amounted only to 3*11 per cent. As the young plants as well as the larger shrubs possess a com- paratively small root-system, and as the amount of moisture in the soil is hardly sufficient for strictly xerophilous plants, it is surprising that a shrub which belongs to a typically hygrophilous order should be able to exist in such a locality. The locality in which I found R. Gorgonias , however, was of the usual nature, consisting of moist sandy soil, on which, among other plants, a species of Drosera , viz. D. cuneifolia , grew. Dr. Purcell has drawn my attention to an article by R. I. Pocock, published in 1898 in Nature 1 , from notes sup- plied by Mr. A. Everett. This gentlemen has observed that a species of Nepenthes in North Borneo is often inhabited by another crab-spider, viz. Misumena nepenthicola. This spider plunges boldly into the fluid of the pitchers whenever threatened by danger, and it is 1 Nature, vol. Iviii, 1898, p. 275. on the Biology of Roridula. 157 assumed that it preys upon the insects which enter the pitcher or which are caught in its fluid. Mr. Mally, of the Cape Entomological Department, has kindly made a general list of the insects found on a handful * of branches .of Roridula dentata , gathered by me on the occasion of my visit to the Tulbagh mountains. This list shows : — Hymenoptera : twenty-five specimens belonging to the sub- families Sphecina and Apina. Diptera: twenty specimens of Muscidae. Coleoptera: Of Coccinellidae were present Chilomenes lunatus , Fab., Exochomus nigromacidatus , Goeze, Pharus sexguttatus , Gyllh. and two other species. Of Scarabaeidae two species were present, viz. Lepitrix stigma , de Geer, and Pritrichia capicola , Fab. Hemiptera : One specimen each of Lygaeidae, Reduviidae and Membracidae. Capetown. May , 1902. On the Heteranthus Section of Cuphea (Lythraceae). BY T. A. SPRAGUE, B.Sc. (Edin.) Assistant in the Herbarium , Royal Gardens , Kew. With Plate XI. History and Taxonomy. HE section Heteranthus was established in 1877 by -1 Koehne ( 3 ), who created it to receive his three new species, Ctiphea setosa , C. epilobiifolia, and C. tetrapetala , which had this character in common that in each pair of opposite flowers one flower was older. He also placed C. rigidula , Benth., doubtfully in the section. In 1881 ( 5 ), while giving more detailed descriptions of his three species, he placed C. rigidula next to C. setosa , omitting all mention of the repeated dichasial branching of C. rigidula , which he evidently did not credit. In succeeding years Koehne added four other species, all from Colombia, one of which, C. Leh - manni , does not possess the character from which the section takes its name, namely the unequal age of the flowers of each pair. The two new species described in the present paper also alter the character of the section in important details, namely the presence of two petals only, and the occurrence of an erect instead of a deflexed disc. It may, therefore, be [Annals of Botany, Vol. XVII. No. LXV. January, 1903.] 160 Sprague. — On the Heteranthus Section useful to give shortly the principal characters of the section Heteranthns as now constituted. Principal characters. Prophylla 2. (Sub-genus Eucuphea .) Flores oppositi, in quovis pari inaequales (exc. C. Lehmanni). Bracteae magnae hypsophylloideae, ciliatae. Caulis saepius pilis fuscis, crassis biseriatim obtectus. Folia opposita. Petala 6, 4, vel 2. Stamina 11 alterne inaequalia. Discus saepius deflexus (in C. tarapotensi erectus). Ovula 3-10. Key to the species (mainly from Koehne). Filamenta inclusa vel parum exserta. C. setosa , C. rigidula , C. sordida. Filamenta valde exserta. I. Petala 6. C. hispidiflora , C. epilobiifolia , C. Buravii , C. Leh- manni. II. Petala 4. C. tetrapetala. III. Petala 2. 1. Discus erectus. C. tarapotensis. 2. Discus deflexus. C. Bombonasae , C. epilobiifolia var. Caquetae , C. tetra- petala var. Cosangae. Cuphea tarapotensis , Sprague, sp. nov. Suffrutex. Caulis (25 cm. circ.) foliaque ut in C. epilobii- folia. Pedicelli 3 mm. longi, ad vel infra medium prophylla ovata acuta ciliata gerentes ; bracteae late ovatae, longe ciliatae. Calyx (5-5*5 mm.) calcare breviusculo recto munitus, fauce ampliata adscendens, dense breviterque hirsutus, intus infra stamina pilosa ; append, lobis breviores, breviter setosae. Petala 2 (dorsalia), quam calyx paullo breviora, ovata of Cuphea ( Lythraceae ). 161 acuminata, ungue longo. Stamina episepala supra lobos \ exserta, epipetalorum breviorum duo dorsalia calycis sinus fere aequantia. Ovarium ovato-oblongum, villosum. Discus erectus, cylindricus, 1*25 mm longus, basi pilosus. Ovula 7-8. R. Spruce , Tarapoto (Peru). Cuphea Bombonasae , Sprague, sp. nov. Suffrutex. Caulis (18-35 cm.) foliaque ut in C. epilobii- folia. Pedicelli 2-3 mm. longi. ad vei supra medium prophylla ovata acuta ciliata gerentes ; bracteae late ovatae, acutae, longe ciliatae. Calyx (5-6 mm.) calcare longiusculo, leviter curvato munitus, fauce ampliata ascendens, dense hirsutus, intus infra stamina pilosa ; append, lobis breviores, brevissime setosae. Petala 2 (dorsalia), calycis §— f aequantia, oblongo- ovata, apice rotundata, ungue lato. Stamina episepala supra lobos | exserta, epipetalorum breviorum duo dorsalia calycis sinus fere aequantia. Ovarium ovatum, pilosum. Discus deflexus, oblique ovoideus, -75 mm. longus. Ovula 6-7. R. Spruce , in fl. Bombonasae ripis inundatis, May, 1857. Cuphea epilobiifolia , Koehne. Var. Caquetae , Sprague, var. nov. Prophylla ovato-oblonga. Calyx 6-8 mm. longus, calcare quam in C. epilobiifolia typica tenuiore. Petala 2 (dorsalia), late ovata vel suborbicularia, salmonea, ungue *75 mm., lamina 3-3*5 mm. longis. Staminum epipetalorum duo dorsalia calycis sinu breviora. Ovula 6-7. Sprague, rocky banks of a tributary of the Caqueta (Colombia), April, 1899. Cuphea tetrapetala, Koehne. Var. Cosangae , Sprague, var. nov. Pedicelli prophylla ad vel supra \ gerentes. Petala pro rata 2 (dorsalia), sed etiam 3-4 inveni, ovata. Staminum epipetalorum postica 2 calycis sinus hand aequantia. Ovula 9. W. Jameson , 775, ad ripas fl. Cosangae (Ecuador), 6,000 ped., Jan. On comparing the descriptions of the species of Heteranthus y the first point noticed is the remarkable uniformity in vegeta- M 1 62 Sprague . — On the Heteranthus Section tive characters, and the very numerous differences in floral structure displayed by the different species. The first is obviously correlated with the similarity of habitat which obtains throughout the group, all the members of which grow in gravelly soil among rocks on the upper courses of rivers. As regards the internal classification of the section, the relationships between the several species are too intricate to admit of any satisfactory natural grouping. C. rigidula is separated sharply from all the rest by the dichasial branch- ing of its inflorescence, and has perhaps its nearest ally in C. setosa. Geography. The following table shows at once that the section is characteristic of the Andes (including in this term the Coast Andes of Venezuela), and in fact inhabits the upper parts of Engler’s subandine (4) region. The only species occurring outside this limit are C. rigidula and C. setosa. We have unfortunately no locality for C. rigidula more precise than Guiana, but it may fairly be assumed from what we know of the habitats of the other species that C. rigidula comes from the mountains of the interior of Guiana, and possibly from the Roraima region. The early isolation of the Guiana mountains would explain the separateness of C. rigidula. Taking C. setosa (distribn. Andes and Tobago) next into consideration, we find that it is really only an apparent exception to the andine distribution of the section, for it is a well-known fact that both Trinidad and Tobago are geologically related rather to the South American mainland than to the other West Indian islands, and form the con- tinuation eastwards of the Coast Andes of Venezuela. The occurrence of C. setosa in Tobago is an excellent illustration of the South American affinity of the flora of that island first remarked by Eggers (6). The distribution of C. epilobiifolia (Andes proper and Venezuelan Coast range) illustrates the truly andine character of the Venezuelan Coast range recently pointed out by of Cuphea ( Lythraceae ). 163 Burkill (7). C. tetrapetala is also of wide distribution, occurring in the Andes from Mexico to Ecuador. The area of the remaining species is much more limited. Finally, we may observe that the centre of development of the section is in Colombia, which possesses no fewer than seven out of the ten species, four of them being endemic. Mexico. Central America. Colombia. Ecuador. Peru. Bolivia. Venezuela. Guiana. ! West Indies. 1 C. setosa . . . ,, rigidula . . ... ... ... ,, sordida . . . • • • „ hispidijlora . „ epilobiifolia . ,, Buravii . . • • . • • • ... ,, Lehmanni „ tetrapetala ... & ... „ Bombonasae . • •• • • . „ tarapotensis . ... £ Total . 2 1 7 2 2 1 1 ■ 1 Biology. All the species of Heteranthus grow among rocks by the side of rivers, and are subjected to periodical inundation ; we find accordingly that they are all perennial and somewhat fruticose, as in such situations annuals would speedily die out unless provided with very special means of propagation. In connexion with the habitat should also be noticed the narrow linear or linear-lanceolate leaves so characteristic of the section. No observations have been recorded as to the pollination of any of the species, but it is abundantly evident from the structure of the flowers that they are entomophilous ; more- over, their position growing gregariously by riversides is a peculiarly favourable one as regards frequency of insect visitors, which in the dense forest crowd at the top of such M 2 , 164 Sprague . — On the He ter ant hits Section trees as are in flower, and only descend in numbers to the ground in open spaces. The reduction of the petals to two in certain species must be regarded as an adaptation to insect pollination rather than as a step towards total loss of petals, for it is significant that the two remaining petals are always the posterior ones, which are situated one on each side of the entrance to the nectariferous calyx spur ; the path to the honey is thus better marked after the loss of the four other petals. The same object is sometimes attained in the six- petalled species of Cuphea by having the two posterior petals much larger or differently coloured ; in C. rigidula they can be distinguished at once by the intense violet colouration of their claws. It is interesting to note that the reduction of petals does not always proceed regularly ; it might have been supposed a priori that the corresponding petals on each side of the flower would have disappeared simultaneously, but this is not the case, e. g. in C. tetrapetala , var. Cosangae , several of the flowers had three petals, the two dorsal and one lateral. It may be as well to state here that buds were examined in every case, to eliminate risk of error from the fugacious nature of the petals. The function of the disc needs investigation ; formerly it was thought to be the honey-producing part of the flower, and was called the gland, but Kerner (2) showed that this idea was erroneous and that the honey is really secreted by the base of the spur. The only explanation since given is that the disc helps to narrow the entrance to the spur, and thus aids in the exclusion of unbidden guests ; while this may be true in some instances, it hardly seems to hold good for all the species of Cuphea. The exclusion of small creeping insects is thoroughly effected in certain species of Cuphea , e. g. C. micrantha , which has the intersepaline teeth provided with glandular hairs. In the section Heteranthus no such efficient protection exists, but the axis of the raceme and the exterior of the calyx of all the species are more or less densely clothed with hairs, C. hispidijiora being especially well provided in this respect. of Cuphea ( Lythraceae ). 165 The tufts of hairs on the base of the filaments of C. rigidula are doubtless of use in restricting access to the honey. In the whole genus Cuphea a peculiar mechanism exists to aid in the distribution of the seeds. After fertilization a mass of tissue just below the ovary grows rapidly and forces the placenta backwards, so that it splits the ovary wall and calyx tube, and finally projects from the posterior side of the flower bearing the ripening seeds. The pollination and insect visitors of C. setosa i and the question of the occurrence or absence of the section in Trinidad, are points well worth the attention of West Indian botanists. In conclusion, I must acknowledge a grant made by the Royal Society towards the expenses of the expedition on which the type of C. epilobiifolia , var. Caquetae was collected. I am indebted to Professor Koehne for a list of the specimens referred by him to the various species and varieties of the section Heteranthus. Bibliography. 1. Koehne, E. : Berichtigung der von D. P. Barcianu gemachten Angaben liber die Bliithenentwickelung bei den Cupheen. (Botanische Zeitung, 1875, PP- 302-7.) 2. Kerner, A. : Die Schutzmittel der Bluthen gegen unberufene Gaste. (Fest- schrift der K. K. Zoolog.-Botan. Gesellschaft in Wien, 1876.) 3. Koehne, E. : Lythraceae in Martii Flora Brasiliensis, xiii, 2, pp. 214-223. 4. Engler, A. : Versuch einer Entwicklungsgeschichte der Pflanzenwelt seit der Tertiarperiode. Leipzig, 1879, 1882. 5. Koehne, E. : Lythraceae in Engler’s Botanische Jahrbiicher, vols. i-vii. 6. Eggers, H. : Die Insel Tobago. (Deutsche Geogr. Blatter, Bremen, xvi (1893), pp. 1-20.) 7. Burkill, I. H. : Report on two Botanical Collections made ... in British Guiana. Introduction. (Trans. Linn. Soc.,ser. 2, Botany, vol. vi, pt. i.) 1 66 Sprague. — Heteranthus Section of Cuphea. EXPLANATION OF THE FIGURES IN PLATE XI. „ Illustrating Mr. Sprague’s paper on Cuphea. Fig. i. C. epilobiifolia , var. Caquetae. Part of plant, mag. nat. Fig. 2. „ Flower from side, x 3-5. Fig. 3. „ Flower opened at back, x 4-5. Figs. 4 and 5. „ Ovary and disc from side and back, x 6. Fig. 6. ,, Ovary opened, showing placenta and ovules, x 6. Fig. 7. C. tetrapetala , var. Cosangae. Flower from side, x 3*75. Fig. 8. „ Flower opened at back (ovary removed), x 4-5. Figs. 9 and 10. ,, Ovary and disc from side and back, x 5*25. Fig. 11. „ Ovary opened, showing placenta and ovules, x 5*25. Fig. 12. C. tarapotensis . Flower from side, x 5. Flower opened at back, x 6*25. Ovary and disc from side and back, x 6*5. Ovary opened, showing placenta and ovules, x 6.5. Flower from side, x 5. Flower opened at back (ovary removed), x 6*25. Ovary and disc from side and back, x 6*5. Ovary opened, showing placenta and ovules, x 6*5. Fig. 13. Figs. 14 and 15. „ Fig. 16. „ Fig. 17. C. Bombonasae. Fig. 18. Figs. 19 and 20. „ Fig. 21. „ Note. — The artist has represented the flowers in Fig. 1 as they were in the dried specimen ; in the living plant the spurs are of course uppermost (posterior) — -T. A. S. / US. Annals of Botany SPRAGUE. CUPHEA. Vol.XVJl PI. XI. University Press, Oxford. S P RAG U E. c U P H EA . Vol.XVJI, PL XI. University Press. Oxford. The Morphology and Development of the Ascocarp in Monascus. BY B. T. P. BARKER, M.A., Gonville and Cams College , Cambridge. With Plates XII and XIII. Source. HE fungus which forms the subject of this paper was -L obtained from a small cake of material which is used in the preparation of an Eastern Asiatic spirit, ‘ Samsu.’ The cake was supplied to me by the kindness of Mr. D. T. Gwynne- Vaughan and Mr. R. H. Yapp, the former of whom collected it during the Skeat Expedition to the Malay Peninsula. A small portion of the cake was added to a flask of sterilized rice, kept at 25° C., and an abundant mycelial growth was quickly formed. This consisted of a mixture of several Fungi, which were separated by the method of fractional plate cultures. Among them was the species here described. It is easily grown in pure cultures on various nutrient media, especially at a temperature of 25-30° C. Growth below 20° C. is very slow. In these cultures a vigorous mycelium is quickly produced, which soon bears numerous conidia in chains. Later the mycelium becomes vividly pigmented with a pig- ment, from a reddish orange to a purple tinge. Ascocarps are then formed abundantly, and all stages in their develop- ment can easily be obtained. [Annals of Botany, Vol. XVII. No. LXV. January, 1903.J 1 68 Barker . — The Morphology and Development of Methods. The methods used for determining the development and structure of the ascocarp in this fungus were twofold, viz. {a) The direct observation of the developing fructification under a Zeiss dz °il immersion lens (eye pieces 4 and 8) in hanging drop cultures. The hanging drops were made of beer-wort agar (beer-wort 98 per cent., agar 2 per cent.), and were infected with conidia from pure cultures of the fungus. The temperature was kept constant at 27° C., this degree being much more suitable for the rapid development of the ascocarps than the ordinary room temperature, growth prac- tically ceasing under i8°C. The results of these observations were checked by the examination of living material, containing developing asco- carps in all stages, under similar powers of magnification. In this manner the results of observations of comparatively few ascocarps, the growth of which had been watched from the start to the formation of the ripe spores, were generalized. (b) The examination of material after killing and staining. The fixing fluid used was the weak Flemming mixture. Ascocarps of various ages were not only examined whole, but also in series of sections, cut by the microtome. The material for these two methods was obtained by different means. For the examination of the entire ascocarps cultures of the fungus in a pure condition were made by infecting a tube of beer-wort with conidia, pouring the infected wort into a sterile Petri dish until the liquid covered the bottom of the dish to a depth of one-eighth to one-quarter of an inch, and then allowing growth to take place at a temperature of 25-27 0 C. The first stages of the ascocarps made their appearance after forty-eight hours ; and at the end of three and four days material was picked out with a sterile platinum needle and fixed. Such material contained ascocarps in all stages. After fixation, it was washed for twenty-four hours in running water and then hardened in a series of alcohols ; the blacken- ing produced by the osmic acid of the fixing fluid was the Ascocarp in Monascus. 169 removed by treatment with hydrogen peroxide ; and it was then stained with safranin for twenty-four hours. After de- hydration with absolute alcohol, the stained material was placed in xylol for a few minutes until perfectly transparent, then teased out carefully and mounted in xylol-balsam. The reason for cultivating the fungus in a thin layer of liquid in a Petri dish was that, when it was grown in any considerable depth of liquid, growth took place more slowly and ascocarps were produced more irregularly and less generally. The material used for section cutting was obtained from plate-cultures on beer-wort agar. Such cultures showed the preliminary stages of fructifications after forty-eight to seventy-two hours from infection with conidia at 25 ~ 27 °C. At intervals of twelve hours portions of the agar, containing the fungus were fixed, washed, and hardened as above. After passing successively through half-alcohol and half-xylol, pure xylol, and xylol-paraffin into paraffin, series of sections were cut by microtome. These were treated in the usual manner, decolorized by hydrogen peroxide and stained by the Flem- ming triple stain. In a few cases the iron-alum haema- toxylin stain was used, but apart from bringing out the conspicuous nucleoli it was unsatisfactory. The cultures on beer-wort agar have a considerable advantage over those in liquid media, in that the formation of ascocarps is general and plentiful throughout, and at the same time at any given moment the majority of them are at approximately the same stage of development. Control is therefore easy. They are, however, unsuited to the previous method of examination, since satisfactory teasing of the agar material is impossible, the agar itself at the same time partially obscuring the fungus. The Development of the Ascocarp. The results obtained from the examination of living material will first be considered. In- a hanging drop-culture of beer-wort agar, infected with 170 Barker . — The Morphology and Development of conidia and kept at 27 0 C, germination soon takes place by the putting out of one or more germ-tubes by a conidium, which at the same time increases slightly in size. The germ-tubes grow rapidly, transverse septa soon appear, and numerous branches are produced (see Fig. 1). In this way a vigorous and abundant mycelium is quickly formed. While the system of branching apparently does not follow any de- finite rule, it nevertheless often happens that the formation of a branch from one side of a hypha is responded to by the formation of another on the opposite side of the hypha, so that an arrangement of the branches in pairs is met with (see Fig. i,e). Another point to be noticed is that there is a considerable tendency on the part of the hyphae to swell at various points (see Fig. i,e). In a few cases the hanging drop almost dried up at the time of germination. In such instances the germinating conidia and hyphae swelled enor- mously, the subsequent branches only regaining the normal size when the drop again became more moist. After about twenty-four hours, the time, however, depending apparently principally upon the amount of mycelium present in proportion to the size of the drop, conidia begin to be formed. These are produced by the swelling of the tips of hyphae into spherical or ovoid bodies, which are then cut off by transverse septa. Chains of these conidia are usually produced by the swelling of the hypha immediately under the terminal conidium, the swollen part being then cut off by a transverse septum to form a second conidium, and the same process being then repeated time after time immediately below the conidium last formed. Such chains may be found, composed of as many as eight to ten conidia, although usually the number is considerably less. The conidia are developed very rapidly at first, but the rate of formation gradually becomes slower until very few fresh ones are formed. It is at about this time that the development of the ascocarps begins, being about twenty-four hours after the formation of the first conidia. The older hyphae are then filled with large vacuoles, and the Ascocctrp in Monctscns. x 7 1 contain many large fatty-looking globules and granules. The side branches, however, are in many cases filled with dense, semi-transparent protoplasm. In certain of these a small terminal cell is cut off by the formation of a transverse septum a little distance below the tip (Fig. 2, o). Immediately below the septum a small lateral protuberance makes its appearance (see Fig. 2, b), the development of which causes the terminal cell to become bent at a slight angle from the direction of growth of the rest of the hypha. This protuberance then becomes the main growing point of the hypha, and no further growth takes place in the direction of the previous growth, but the developing hypha instead becomes closely applied to the stationary terminal cell and following its course, at the same time pushing it more and more from its original position, until eventually it assumes a direction more or less at right angles to the parent hypha (see Fig. 2, c, d , e ). The terminal cell usually grows but little after its formation, .but in some cases a more considerable increase in length, and even branching and conidial formation, occur (see Fig. 3, a and b). Occasionally a similar process occurs at a considerable distance from the tip of a hypha, the new growing point developing immediately beneath a transverse septum and proceeding, as in the previous case, to bend the apical portion of the hypha from its original course (see Fig. 4); on some occasions also immediately beneath a conidium (see Fig. 6), or beneath the lowest member of a chain of conidia (see Fig. 7). In both instances the subsequent development of the new growing point is similar. As already stated, it grows into a small hypha closely applied to the apical portion of the original hypha. Its course along this is usually almost strictly parallel with it but slightly curling round it, but in some cases a very pronounced spiral winding occurs, to the extent at times of more than one complete revolution (see Fig. 5). The growth in length of this hypha is limited, rarely exceeding 40 ju. By the time that the limit of its growth in length has been reached, a septum has been formed in the neighbourhood of its point of origin (see 1J2 Barker . — The Morphology and Development of Fig. 2, e). The formation of the septum at this point marks off a single cell, composed of the whole of the small hypha developed as the result of the growth of the small pro- tuberance or new growing point mentioned above. This cell, for reasons given later, will be henceforward termed the ascogonium , while the original terminal cell of the parent hypha, clasped by the ascogonium, will be described as the antheridial branch. In those instances in which the asco- gonium has been produced at some distance from the apex of the parent hypha, that portion, the direction of which has been deflected by the growth of the ascogonium, will be regarded as the antheridial branch. There have now been formed two organs, the ascogonium and the antheridial branch, the subsequent behaviour of which leads to the production of the ascocarp. They must there- fore be regarded as the archicarp. Both of them at this period are filled with derise semi-transparent protoplasm, devoid of vacuoles but containing a few bright granules. The next step in the development of the ascocarp consists in a fusion between the two organs. The fusion takes place in most cases at the tip of the ascogonium, between that portion of it and the part of the antheridial branch in its immediate neighbourhood (see Fig. 2,/). Occasionally, how- ever, fusion takes place a little distance below the tip of the ascogonium (see Fig. 8 ). The fusion appears to take place in the following manner. A small papillar outgrowth is developed on the antheridial branch at the point, where fusion eventu- ally takes place, between that organ and the closely applied ascogonium. Solution of the walls then occurs at the point of contact between the papilla and the ascogonium, the proto- plasm of the two organs becoming continuous. There are two reasons for supposing the fusion to take place in this manner. Firstly, when the fused portion has become more conspicuous, the antheridial branch at the place of fusion is slightly swollen on the side in contact with the ascogonium and apparently projects into it. That is to say, it is the wall of the antheridium that constitutes the wall of the communi- the As cocarp in Monascus. 173 eating canal between the two hyphae (see Fig. 9). Secondly, in certain cases no fusion takes place and no ascocarp is developed ; but, nevertheless, a small papilla is developed on the antheridial branch between it and the closely applied ascogonium, or, in some cases, where the ascogonium only partially develops, at the place where the tip of the ascogonium would normally be (see Fig. 10). The exact moment of fusion is very difficult to determine in most cases, since the close contact between the two organs and their optical properties are such as to obscure almost completely the details of the process. I have never observed, either in the living state or in the fixed and stained material, a case of which it could be stated positively that fusion had occurred before the formation of the septum cutting off the ascogonium. I have, however, seen instances of undoubted fusion after the formation of the septum but before the occurrence of the next stage about to be described. It seems probable, therefore, that fusion succeeds the cutting off of the ascogonium, and is preliminary to and also necessary for the development of the subsequent stages. With regard to the necessity for fusion, I have never seen a developing ascocarp, in which the archicarp was still visible, that did not show perfectly clearly the existence of a fusion between the antheridial branch and the ascogonium. It should be mentioned here also that, while the fusion is practically invisible under a one-sixth inch objective and often under a one-twelfth inch oil immersion objective in the early stages of the developing ascocarp, it becomes easily visible later, when swelling and the degeneration of the contents of the antheridial branch and of the tip of the ascogonium occur. Positive proof of the existence of a fusion at quite an early stage is forthcoming, however, since I have seen granules pass from the ascogonium into the antheridial branch, and vice versa, in specimens in the stage now about to be described. This stage consists in the cutting off of a cell in the ascogonium by the formation of a septum across that organ between the place of fusion and the septum at its base 174 Barker . — The Morphology and Development of (see Fig. 2 ,g). The penultimate cell thus cut off varies con- siderably in size at the time of formation (see Figs. 2,g; 3, b ; and 5), but in all cases it has dense semi-transparent slightly granular protoplasmic contents and practically no vacuoles. It is from this penultimate cell that the ‘ sporangium * of previous authors is developed. On account of its importance and position I propose to term it the ‘ central cell/ the older terms ‘ sporangium * and £ ascus 5 being, as will be seen later, erroneous. It soon begins to swell up, and vacuoles make their appear- ance, its shape during the earlier period of swelling being more or less reniform or bean-shaped (see Fig. 2,/z). Later it becomes spheroid or ovoid. The ascogonium consists during this period of two cells, viz. the central cell and a cell at its apex, which is made up of that portion of the organ which has taken part in the fusion with the antheridial branch, and is more or less comparable to a ‘trichogyne’ (see Fig. 2 , g, &c.). Shortly after the formation of the central cell, investing hyphae begin to be formed around it. These are developed from the hypha which has produced the archicarp, and arise from that part of it immediately below the limiting septum of the ascogonium, i.e. just below the central cell. In most cases a single hypha is produced in that region ; and this proceeds to grow up around the central cell, closely applied to it (see Fig. 11, a). It begins very quickly to put out lateral branches, which also clasp the central cell. The lateral branches, especially the earlier ones, are usually pro- duced in pairs, and grow in opposite directions. These, in their turn, produce other branches, also clasping the central cell ; and development in this manner continues until the cen- tral cell is covered on every side, except those in contact with the antheridial branch and ‘ trichogyne cell,’ by investing hyphae. The growth of these hyphae then ceases (see Fig. 11, d-d). In speaking of the central cell as being invested on every side by these hyphae, it must not be understood that the whole surface is completely covered by them. What is the A sco carp in Monascus. 175 meant is that there is no large continuous surface left un- covered and unclasped, on every side by investing hyphae. But here and there the clasping hyphae leave exposed small portions of the surface of the central cell, and in this sense the investment is incomplete. Nevertheless, the whole of the central cell is clasped by the hyphae (see Figs. 11, d ; and 12). In some cases the main investing hypha does not itself become closely applied to the central cell, this function being left to some of its branches and their succeeding branches (see Fig. 12). In other cases, after growing closely applied to the cell for part of its course, it continues to grow for some distance beyond it (see Fig. 11, a). Occasionally also some of its branches do not become closely applied to the central cell (see Fig. 12). In those cases which have been described up to the present, all the investing hyphae have originated from a single outgrowth from the main hypha, just beneath the ascogonium. Occasionally, however, the investment of the central cell is completed by the growth of one or more other hyphae from the same region (see Fig. 12). The development of investing hyphae is often followed by the development of small branched hyphae on other parts of the hypha bearing the ascocarp. They are sometimes irregularly branched, but often the branches are produced in pairs and grow in a curved manner, as if clasping a spherical body. Fig. 14 shows examples of both kinds. The details of the development of the investing hyphae are seen fairly easily in the earlier stages under an immersion lens, but with lower powers of magnification they can be but imperfectly traced. In the later stages, even with the use of high * powers of magnification, it becomes very difficult to observe with certainty what is happening. The hyphae are at first very small, compared with the ordinary hyphae of the fungus and with the archicarp. Their protoplasm is very dense and less transparent than that of the central cell. Consequently the course of development 176 Barker . — The Morphology and Development of of the earlier branches is easily traced. Later, however, the hyphae begin to swell, and become more transparent, and, after further growth in length and branching have ceased, the individual hyphae are very indistinctly seen, and the system could not be correctly figured if the development from a very early stage were not followed. Further swelling and, at the same time, flattening out render them, except in a few cases here and there, almost invisible. A large number of oil drops also appear, gradually increasing in size. Later still, after the protoplasmic contents seem to have entirely degenerated and to have disappeared, they appear as nothing more than flattened walls (see Fig. 13, a-c). At this stage the fructification has acquired a brownish colour, due no doubt to these degenerated hyphae. While all these changes have been taking place, important developments of the central cell have occurred. These can be seen but indistinctly owing to the obscuring effect of the investing hyphae, particularly about the period of swelling up and flattening of those structures. At the time of the forma- tion of the first investing hypha, the central cell is compara- tively small, although as has been stated above, swelling has already begun to occur. The swelling continues during the formation of the hyphae, to such an extent that the whole fructification becomes a conspicuous and comparatively large body. By this time the contents of the antheridial branch and the ‘ trichogyne cell ’ have become disorganized and eventually disappear. At the same time those two structures have swollen considerably, and the fusion between them is then very easily seen. Later, their walls collapse, and in most cases all traces of their existence are lost (see Fig. 13, a , b , c). When the growth of the investing hyphae has ceased the central cell can still be seen, although with difficulty. Its outlines are no longer sharply marked ; but here and there portions of its surface can be sharply focussed, where the absence of investing hyphae has left it exposed. Later, when the hyphae begin to swell and become flattened out, such the A scocarp in Monascus. 1 7 7 parts of the surface are seen to bulge slightly, as though there were considerable pressure being exerted inside, which forced an expansion at the unclasped points. In a few cases I have seen a comparatively conspicuous bulging at one point of the ascocarp. This may be an impor- tant fact, and will be referred to later as possibly repre- senting the formation of the first ascogenous hypha (see Fig. 11, a). After this stage the optical effects produced by the swollen central cell and the swelling and flattening investing hyphae, together with the innumerable oil drops, render further details invisible for some considerable period in the development of the ascocarp. The general impressions produced up to the stage when the contents of the interior of the fructification again become visible are as follows : — At some part of the interior a small spherical space becomes visible. This is clearly defined on account of its optical properties differing from those of the rest of the ascocarp. The position of this space is not necessarily the same in all cases. Sometimes it appears towards one side of the ascocarp and sometimes apparently in the centre (see Fig. 13, a). It increases in size until it fills almost the whole of the interior of the fructification. As it increases in size it loses its apparent homogenous appearance ; and soon, when compara- tively large, presents the appearance of being filled with numerous large vacuoles. This apparent structure remains until the contents of the ascocarp become more clearly visible (see Fig. 13, b). As the contents gradually become more clearly visible, the misty appearance which has hitherto obscured the develop- ment is slowly lost, and it becomes possible to distinguish by degrees a mass of branching hyphae in the centre of the ascocarp, occupying the previous vacuolated space. It is undoubtedly to these hyphae that the appearance of c vacuola- tion ’ was due. The courses of the hyphae cannot be traced, since the N 178 Barker . — The Morphology and Development of interior is filled with such a tangled mass of hyphae and structureless material that the lower ones are obscured. Some of the hyphae are much larger than others, and are much vacuolated. Others are of varying sizes, but filled with dense protoplasm. Soon it can be seen that some of the latter have become spherical in shape, and in these, after a short time, spores are formed, eight spores in each (see Fig. 13 , 4 There can be no doubt that these spore-containing hyphal branches are in reality asci. The other hyphae and also the walls of the asci soon disin- tegrate and the spores are set free in the interior of the fructification, mixed with a mass of debris. In this way the mature ascocarp is formed. It appears to be nothing more than a spherical body, consisting of a struc- tureless brown wall enclosing a mass of spores mixed with mucilaginous substance. It might certainly be mistaken for a sporangium. The spores are liberated from this structure by the breaking down of the wall. The ripe spores are very characteristic in appearance. They have a reddish-brown colour, a bright yet almost opaque look, and in shape are ovoid with pointed ends. Their size is about 8 \x by 4 \x. This account of the development of the ascocarp derived from the study of living material is supplemented by observa- tion of fixed and stained material, an account of which will now be given. Owing to the comparatively small size of the mature asco- carps and the transparency of all stages after mounting whole in Canada balsam, very few additional details have been gained by the study of series of sections beyond those ob- tained by the observation of uncut, stained, and teased material ; so that the results of the two methods may well be considered together. The series of sections of the various stages have an advantage over the teased material in that the nuclei are much more conspicuous, and the branching of the the A sco carp in Monascus . 179 hyphae from which the asci are eventually developed may be to some extent traced ; but they have considerable disadvan- tages. Not only is there some difficulty in finding all the members of a series of sections of an ascocarp and of piecing them together accurately, but also in the cutting of the series the sections of the ascocarp become crushed or partially folded up, and in the subsequent floating out of the sections in hot water complete unfolding often does not take place; in particular great difficulty is experienced in distinguishing between certain portions of the central cell and the investing hyphae. Starting with the formation of the ascocarp, the chief interest in the stained material is fixed on the behaviour of the nuclei. On the whole the iron-alum haematoxylin method of staining is the most satisfactory for the nuclear work. The cells of the mycelium are multinucleate, and the same appears to be the case with the conidia from the time of their formation. The growing points of the hyphae, particularly those of the archicarp-bearing hyphae, are crowded with nuclei. The nuclei appear to stain in two ways. In the young hyphae and the archicarps the nuclei are distinguishable separately only by their nucleoli, which stain very deeply and are relatively large, the bodies of such nuclei being apparently almost unstained, each thus appearing as a light spherical space containing a deeply stained granule. The protoplasm stains rather deeply in these portions of the mycelium, not so deeply as the nucleoli, but darker than the bodies of the nuclei, this doubtless being due to the presence of some substance pecu- liar to the protoplasm of young hyphae which has a strong affinity for stains. On this account, and owing also to the large number of nuclei present in these parts, it is almost impossible to define the limits of any particular nucleus. Their numbers are indicated by the number of nucleoli. In the older hyphae the bodies of the nuclei stain rather deeply and almost uniformly, but no nucleolus is conspicuous, and the protoplasm with haematoxylin is almost unstained. 180 Barker .— The Morphology and Development of They are thus clearly defined. In certain parts, particularly in the antheridial branches after fusion with the ascogonia, an intermediate method of staining is found. The bodies of the nuclei stain uniformly but not deeply, while a distinct network of more deeply stained material is visible and an inconspicuous nucleolus is usually seen. In both the antheridial branch and the young ascogonium there are numerous nuclei. At the time of fusion several may be found in both organs close to the place where fusion occurs, especially in the antheridial branch (Fig. 15 a). After fusion no doubt a migration of nuclei occurs from the latter into the ascogonium. At this time the canal between the two organs is practically indistinguishable, and it is impossible to deter- mine clearly if nuclei are situated in it. The occurrence of several nuclei in its neighbourhood is, however, significant ; and in many cases nuclei appear to occupy the passage (Fig. 15, a). At a slightly later stage, when the canal is more easily seen and the central cell has been cut off by the formation of a wall, a nucleus can occa- sionally be found in the passage (see Fig. 15, b). The ascogonium, after fusion with the antheridial branch, contains a large number of nuclei ; and the central cell, when it is first cut off, seems to be almost entirely filled with them. They are not clearly defined on account of the affinity of the protoplasm for the stain and the slight staining capacity of their bodies. Their nucleoli alone are conspicuous (Fig. 15, b). Later, as the central cell grows larger, they are found grouped together at its centre in a dense mass (see Fig. 1 5, c ). The surrounding protoplasm is almost unstained, the nuclear bodies are now more darkly stained, and the nucleoli are not quite so conspicuous. Finally, when the central cell has attained a considerable size and is completely invested, the nuclei are scattered irregularly in it and are stained rather deeply and more uniformly. In the ascogenous hyphae the nuclei are not clearly defined, the staining of the younger branches being in particular very diffuse. Occasionally a few are found which show a structure similar to those of the the A sco carp in Monas cus. 1 8 1 young ascogonium, but usually they are only to be dis- tinguished from the surrounding protoplasm by being stained rather more deeply. At the time when it is first possible to distinguish with certainty the young asci as such, four or eight nuclei are usually found in each. Eventually eight nuclei are formed in each ascus, and the spores are produced by the accumulation of protoplasm around each nucleus. The small size of the archicarp renders it impossible to speak with more certainty of the nuclear behaviour during the earlier periods of the formation of the ascocarp. The nuclei are relatively numerous, and consequently in whatever posi- tion the young ascogonium is viewed, even in sections, some are always superposed above the others. This fact gives rise in most instances to appearances of nuclear fusions, the majority of which by very careful observation can be made out to be due simply to superposition. Some cases cannot be clearly determined. The nuclei are so small and the amount of stainable substance in them is so inconsiderable, being especially marked owing to the stained protoplasm, rendering them comparatively transparent and therefore almost inde- terminable in regard to their boundaries, that a positive state- ment as to fusion in such cases cannot be given. Nevertheless it is highly probable that fusions occur. There is an undoubted fusion between the antheridial branch and the young ascogonium, the extent of the fusion never being much greater than will permit of the passage of nuclei. That nuclei do pass from one organ to the other at some period is certain, since they have been found in the communi- cating canal. The fusion always takes place prior to the formation of the wall across the archegonium, which cuts off the central cell, so that the inference is that a nucleus or nuclei passed from the antheridial branch into that region of the ascogonium before the formation of the wall. Probably many nuclei pass, since, after the central cell is cut off ; it is found to be crowded with nuclei, while the number of nuclei in the antheridial branch seems to be less than in rather younger branches. Having admitted the 182 Barker. — The Morphology and Development of extreme likelihood of the course of events up to this point, supported as they are by direct observation, by every analogy it follows that the male nucleus or nuclei fuse with female nuclei in pairs in the central cell. The absence of one or two specially large or conspicuous nuclei supports the view that numerous fusions occur. The time of the occurrence of the fusions is probably during the state of aggregation of nuclei, at the centre of the central cell, when it is beginning to swell. Confirmation of this interpretation of the nuclear behaviour is forthcoming by the analogy of Pyronema. As Harper has shown (10), a ‘pore’ fusion occurs in this fungus between the trichogyne and the antheridium. Numerous nuclei pass from the latter through the trichogyne into the ascogonium, which then forms a wall at the base of the trichogyne, a cell analo- gous to the central cell of Monascus thus being produced. Its nuclei aggregate at its centre, the male nuclei also travelling to that position, and numerous fusions in pairs then occur between the male and female nuclei. Similar multiple fusions have been shown by Stevens to occur in the oospheres of Albugo Bliti (20) and Albugo PorHdacae (21), the details of the processes being essentially the same as in Pyronema. There is therefore considerable ground for believing that the nuclear behaviour in the archicarp of Monascus consists in numerous fusions in pairs of male and female nuclei in the central cell. It has not been possible to distinguish nuclei in the act of division. It is probable, however, that some of the nuclei, which have been described above as having a structure con- sisting of a deeply stained nucleolus and an unstained nuclear body, are actually nuclei in course of division. If this is so, the structure which has been described above as the nucleolus consists probably of the individual chromosomes grouped closely together in one of the stages of karyokinesis, and appearing on account of the small size of the nucleus and nuclear figures as a single homogeneous structure. The some- what irregular shape of the ‘ nucleolus ’ in some instances lends colour to this view, which is also supported by the facts the Ascocarp in Monascus. 183 that such nuclei are only found in young, actively growing hyphae, where dividing nuclei must certainly occur, and that the limits of the nuclei in these regions are very difficult to determine. It is noteworthy, also, that when the conspicuous ‘ nucleolus ’ disappears from a nucleus, the latter becomes more definite, and can be distinguished as a sharply marked spherical body with a reticulate network. If this view is correct, we have in Monascus another instance of active nuclear division preceding the formation of male and female gametes, so characteristic of the Oomycetes and Pyronema . During the formation of the first few investing hyphae, nothing of peculiar interest is seen, except that the central cell increases considerably in size (see Fig. 16). During this time it stains conspicuously, and can easily be seen. As the development of the investing hyphae proceeds, the central cell still goes on increasing in size, but stains less and less con- spicuously, until at last, in many cases, all sight of it is lost. Both sections and teased material at this stage represent apparently the ascocarp as possessing only numerous small hyphae (see Figs. 17 and 18). This appearance, however, is misleading. For in the teased material careful focussing reveals the fact that the hyphae apparently within the asco- carp are in reality some of the investing hyphae, which, staining deeply, appear to be within the ascocarp, though they are actually merely in view through the unseen central cell. This illusion is heightened by the fact that the latter is ovoid or spherical, so that at every plane some of the investing hyphae are sharply in focus. In the sections it is impossible to get the ascocarps cut sufficiently thin to show a section of the central cell only with a ring of investing hyphae around it. Owing to their small size at this stage some of the investing hyphae either above or below it are sure to be included in the section, and these produce the illusion. Such appearances cease when the investing hyphae reach the swelling and flattening stage, the continued growth of the central cell also aiding the alteration. The investing hyphae above and below the central cell now become much more 184 Barker . — The Morphology and Development of indistinct, and their course can hardly be traced. The only positions where they are clearly visible are at the sides of the central cell. The latter in consequence becomes clear in outline again, and its further development can be followed. Its structure at this stage seems to be very variable. On rare occasions it is a large, more or less spherical cell, filled with much vacuolated protoplasm and containing numerous nuclei (see Fig. 19). Sometimes it appears as a large spherical cell — as in the preceding case, but with a prominent protuberance at some point of its surface (see Fig. 30). More usually, however, it is a spherical body with a round cavity developed at some point within it. In this cavity is a greater or less number of hyphae, deeply stained for the most part and very conspicuous. The size and position of this cavity are very variable in ascocarps of the same size. In some the cavity is very small, is situated close to the surface of the cell, apparently coming to the surface at some point, and contains very few hyphae. Fig. 21 shows a case in which only a single hypha is present. Figs. 22, 23, 24 show instances in which only a few branching hyphae are developed. At the same time these figures show the varying positions of the cavity with reference to that of the stalk of the ascocarp, i.e. the main hypha from which the archicarp was developed. In other instances the cavity is much larger and contains many hyphae, some small and conspicuously stained and others larger and much vacuolated. The cavity then occupies a large part of the interior of the central cell, sometimes occupying it so fully that the latter is nothing more than a thin double envelope of varying thickness, and often very difficult to distinguish from some of the investing hyphae. Figs. 25-28 represent this stage in various degrees. The teased preparations show these examples much more clearly than the sections, since there is considerable confusion in the latter between the sections of the thinner parts of the central cell and the sections of the investing hyphae. The sections, however, show that in most cases in the cavity there the Ascocarp in Monas cits. 185 is a large deeply-stained central hypha with many prominent nuclei, and around this, in a circle, are other smaller hyphae which seem to arise as lateral branches of the central hypha (see Figs. 23-27). In young stages there appear to be three main hyphae in the cavity, one the prominent central hypha, and the other two springing as opposite branches from this. The main central hypha thus seems to branch in a manner similar to that of the main investing hypha. Each of these hyphae branches freely later, and produces within the cavity a densely-woven mass of hyphae of various sizes. Only the small, young hyphae then stain deeply, the older ones becoming quickly filled with large vacuoles and staining but little. In later stages these swell so much and are almost unstained, so that it becomes impossible to trace their course. As the ascocarps increase in size, the size of the cavity in the central cell becomes much greater and the mass of hyphae within it very considerable. The central cell, in a sense, seems to develop accordingly, so that the whole ascocarp is composed practically of a solid tissue. A section across such an one shows an external ring of investing hyphae, very much flattened out and consisting of very little more than cell- walls ; these are not contiguous, so that the ring is incomplete : then comes a complete ring of tissue, consisting of a section across the central cell ; it has both an outer and an inner wall, and is of varying thickness. In most sections, completely enclosed by this ring, is the central cavity, filled with branching hyphae of various sizes (see Figs. 25-32). After this stage degeneration seems to take place in the ascocarp. The internal hyphae become mixed up with a structureless substance, probably mucilaginous in nature* and produced by the breaking down of some of the older ones. Some of the branches swell up into spherical bodies, the young asci, in which eight small darkly-stained round masses appear. These are the early stages of the spores. They increase in size and eventually become developed into ripe spores, ovoid in shape, with pointed ends and thick walls. The wall of the ascocarp consists now of a complete brownish 1 86 Barker . — The Morphology and Development of structureless thin layer of cellulose-like material, which doubt- less is made up of the empty walls of both the investing hyphae and the degenerated central cell. Fig. 32 shows ascocarps at this stage, containing some asci with rudimentary spores and others with ripe spores. Further degeneration takes place within the ascocarp, the ripe spores being liberated from the asci and the remainder of the internal hyphae breaking down completely, a pseudo-sporangium being thus produced (Fig. 33). It has been mentioned above that the central cell in some cases shows a conspicuous protuberance. This is not only seen in cases in which no cavity exists in the central cell, but also in instances where the cavity is of considerable size. In the teased preparations I have endeavoured to trace the course of such protuberances in the latter instances. As far as I can make out, the protuberance seems to be an actual outgrowth of the central cell which grows over the surface of the latter, closely applied to it, until it reaches the neighbourhood of the central cavity ; then, at the point where the cavity comes nearest to the surface, it appears to penetrate into it and become continuous with the main hypha within it. I do not state positively that this is actually the case, seeing that the protuberance is not differentiated in the least from the central cell by staining, and bearing in mind that the shadow of an investing hypha may give rise to the appearance of the continuation of the protuberance above or below the central cell. But, at any rate, at certain planes the existence of such a protuberance directly from the central cell, and entirely independent of investing hyphae, is most plainly seen, and it is only about its length and course that any doubt is felt. Fig. 34 shows an example of these appearances. In sections I have not been able to trace the course of such protuberances owing to the confusing effect of the investing hyphae. We are now, more or less, in a position to discuss the morphological nature and mode of formation of the ascocarp from the evidence furnished by these results. the Ascocarp in Monascus . 187 The ascocarp evidently arises from an archicarp, as is the case with many other Ascomycetes, e. g. Sphaerotheca and Pyronema. The archicarp here consists of two organs ; one a male organ, the antheridial branch, and the other, the ascogonium, or female organ. A sexual process, represented by an undoubted fusion between the two, and probably also by multiple fusion between male and female nuclei, undoubtedly occurs, the antheridial branch appearing to take the most active part in the process of fusion as indicated by the forma- tion of the small papilla. As a result of this process, a fertilized cell, the central cell, is formed. From this, with the aid of the investing hyphae, the development of which seems to be called forth by the act of fertilization, the ascocarp is produced. The central cell swells enormously, the investing hyphae keeping pace with it at first by active growth, and later, when this ceases, by swelling and flattening. The latter effect is doubtless produced by continued growth of the central cell, which is also illustrated by the slight bulging that takes place at those portions of its surface which are uncovered by investing hyphae. The next step in the development consists in the formation of ascogenous hyphae from the central cell. It has not been possible to observe the earliest formation of these hyphae, owing among other things to difficulties in distinguishing them from investing hyphae. Nevertheless at a very young stage they have been observed as short-coiled comparatively stout hyphae situated in a kind of little nest or depression in the side of the central cell. The first appearance of this nest always coincides in point of time with the first appearance of the ascogenous hyphae as such, and it has been seen at a stage so early that it has been completely occupied by a single short-coiled hypha. It is then very small com- pared with the size of the central cell, and is always situated at some point of the surface of the latter, its exact position varying in different instances. It soon begins to increase in size, being all the while completely filled with closely entwined hyphae. Its growth continues, until it occupies almost the whole of the interior of the ascocarp. The ascogenous hyphae 1 88 Barker . — The Morphology and Development of eventually produce small spherical eight-spored asci. The asci are very thin-walled, and soon break down, liberating the spores into the cavity of the nest, and at the same time the ascogenous hyphae also degenerate, so that the ripe ascocarp is filled with a large number of spores lying free in its interior amid a mass of mucilaginous substance produced by the degeneration of the other structures. During this time the central cell has undergone many changes. The nest of asco- genous hyphae in its growth displaces it and causes a con- siderable alteration in its shape. As the nest increases in size, it penetrates towards the centre of the central cell, which, in its growth, closes over it, so as to make it appear as if it were an internal development. Eventually the central cell ceases to grow, but the ascogenous hyphae continue to enlarge the size of the nest until asci are formed, thus causing the sur- rounding wall, which consists of the hollowed-out central cell, to become stretched and therefore thinner. The contents gradually disappear and the walls become cutinized, so that finally nothing remains of the central cell but its walls, which form a complete envelope around the asci and ascogenous hyphae. At first spherical, it thus gradually becomes changed in shape to a hollow sphere by the formation of a depression at one point, which extends by degrees to its centre, the mouth of the depression being roofed over by its growth. The depression itself is caused by the formation of ascogenous hyphae and its enlargement is due to the growth of these structures. The ripe ascocarp is thus a simple sporangium-like structure — a pseudo-sporangium. The complicated interme- diate stages of its formation are due entirely to the curious behaviour of the central cell in growing around and thus enclosing the earliest formed ascogenous hyphae. It is thus in reality very simple in origin. No other satisfactory interpretation of the structures ob- served during the development of the ascocarp seems possible. The ascogenous hyphae must arise from the central cell, since no trace of a possible origin from the investing hyphae has been seen. In specimens of fixed material mounted in the Ascocarp in Monas cus . 189 balsam the central cell and its contained structures shrink away from the investing hyphae, so that it can be seen that no outgrowth from these into the central cell has given rise to the ascogenous hyphae. Moreover, it would be contrary to every analogy if they had such an origin. Another possible cause of the curious behaviour of the central cell might be that ascogenous hyphae are produced at one point of its surface, and these, during growth, press against the investing hyphae so as to force their bases into the central cell and thus displace it, so that it surrounds them. But evidence is against this view. Nowhere can the ascogenous hyphae be seen to touch the investing hyphae, and their tips are as a matter of fact directed towards the centre of the central cell, so that during growth they tend to push themselves in or their bases outwards. An actual internal development is also quite out of the question. An investigation of young ascocarps shows that the nest invariably arises at some point on the surface of the central cell. It is highly probable that the ascogenous hyphae have their origin from a single outgrowth of the central cell. I have never seen a case in which two nests of hyphae have been formed in the same central cell, and, as far as can be ascer- tained by careful examination of the youngest nests, they appear to be composed of a single coiled unbranched or slightly branched hypha. Later this branches very freely. It is difficult to see why the first ascogenous hypha should remain in close contact with the central cell and eventually become enclosed by it. One would naturally expect to find it growing out through one of the interstices of the investing hyphae, as in the case of Pyronema . Perhaps the same attraction which causes the investing hyphae to grow closely applied to the central cell holds good for it also. Un- doubtedly its behaviour results in the functions of protec- tion and nutrition being very efficiently performed for the ascogenous hyphae by the central cell and the investing hyphae. ^ 19 ° Barker . — The Morphology and Developments f Historical. Van Tieghem ( 24 ) in 1884 published an account of two hitherto undescribed Fungi, which he classed with the Ascomycetes and placed among the Perisporiaceae with such little known forms as Apiosporium and Cys to theca. He con- sidered them as constituting a new genus, which he named Monascns , having as its distinctive feature a novel form of perithecium. As its name implies, the perithecium consisted of a single ascus, invested by a covering of sterile hyphae, the small spherical body thus produced being regarded as the perithecium. The ascus itself was peculiar, in that it was for such a structure comparatively large and many- spored. Indeed, except for its cutinized wall and the absence of any columella, it resembled a sporangium much more than a typical ascus. To describe the species somewhat in detail, one form, Monascns ruber , consisted of a much-branched regularly- septate mycelium which produced under culture two forms of reproductive organs. In the earlier stages of the cultures conidia were formed abundantly. These were produced at the end of branches in rows of varying numbers, being formed basi- petally. They were colourless and somewhat spherical bodies, in size usually 10-12 \x.. Later the second type of reproduc- tion was developed. From one of the hyphae of the my- celium a short erect branch arose, which soon ceased to grow and began to swell at its apex. Immediately beneath the swollen tip a wall was formed, cutting off a terminal hemi- spherical cell. The other part of the branch was divided by two or three transverse walls. Beneath the terminal cell a whorl of branches was produced. These ramified and grew around it, until it was completely covered by them, without however being absolutely in contact with them until later. Contact was established eventually by the continued swelling of the terminal cell, which in the end attained a size of 40-54 \x. At this period it was brick-red in colour. During its swelling the contents of the investing hyphae gradually the A sco carp in Mona sens. 19 1 disappeared, their walls finally collapsing so that their presence was only indicated by apparent reticulated thicken- ings of its walls. Its coloured protoplasm at length became colourless, and divided into a very large number of small oval masses, each of which became a spore. The ripe spores were oval, colourless, and refringent with homogeneous protoplasm. They measured 7-8 \x and 4-5 m. They were liberated by the breaking down of the wall. The perithecium sometimes remained very much smaller and contained but few spores, e. g. 16 \i in diameter with 8-10 spores, and 11 ft with only 4 spores. The other species, Monascus mucoroides , differed from the preceding but little except in size. The conidia were larger, being usually 15-18 ^ i n diameter. The perithecia were also larger, having a diameter of 60-70 ft, and were produced at the end of a long branch or pedicel, in this respect resembling a Mucor sporangium even more than the preceding. Hence its name. The ascospores were spherical, with a mean diameter of 8 \x . The investing hyphae were similar ; but in the early stages, while grouping them- selves around the ascus as in the preceding species, they were not so closely applied to it, a considerable space being left between them and it, contact not being established until the latter had almost reached its full size. On this account Van Tieghem considered that there was no sexual relation between the ascogenous cell and any of the investing hyphae. The next account of a member of this genus was that given by Harz in 1890 ( 12 ). Under the name Physomyces heterosporus he has described a fungus which undoubtedly is a member of Van Tieghem’s genus, Monascus. It was met with in solutions of glycerine in a soap-factory in Bavaria, and attracted attention by its vivid carmine-red pigment. Its methods of reproduction were very similar to those of the preceding species. On nutrient gelatine substrata two kinds of conidia were formed, viz. torula-like conidia, borne either singly or in chains, 2*5-3*5 /x in diameter, corresponding to the conidia described by Van Tieghem, and macro-conidia, borne singly, more or less egg-shaped, and larger than the 192 Barker. — The Morphology and Development of preceding. The characteristic perithecia were not produced on gelatine substrata, but were soon developed in liquid media. The earliest stages of their development, which this author found, showed two or three small cells 3-4 \x in width and 2-4 times that length, situated at the apex of a branch. One of these was apparently the terminal cell of the branch, while the other one or two were placed somewhat at its side. From the central cell the f sporangium ’ was eventually pro- duced, and he hence considered it as an oogonium. Whether either of the other cells represented an antheridium he left undecided. Further observation of these structures was soon rendered impossible by the growth of investing hyphae from beneath the oogonium. By the time that the young fructifi- cation had reached the size 15-18 /x the oogonium was com- pletely covered by these hyphae. The ripe fruits were spherical, 40-53 \x in diameter, and containing numerous spherical, or slightly oval, hyaline, thick-walled, colourless, refringent spores of 4*5~5*i /x diameter. Sections of unripe fructifications, fixed in alcohol, showed the central oogonium filled with dense protoplasm and fat-drops of various sizes, surrounded by a layer of investing hyphae. Later stages showed the protoplasm regularly granular ; and finally the oogonium was found filled with numerous spores, in the early stages of formation polygonal, and later more or less rounded and thick-walled. The optimum temperature of growth of this species was 30-31 C. The mycelium was freely divided by septa. Harz seems to have been ignorant of Van Tieghem’s paper, a knowledge of which, in spite of the absence of figures accompanying it, would at once have shown him that he had to deal with a form of Monascus. As it was, while considering that it showed affinities with the Oomycetes, he constructed a new order, the Leptoomycetes, in which he included it with a few other little known Fungi, e. g. Helicosporangium parasiticum , Karsten, and P apulaspor a sepedonioides , Preuss. To it he gave the name Physomyces heterosporus. the Ascocarp in Monascus. 193 In the following year Brefeld (2) published his researches on Ascoidea , Protomyces , and Thelebolus , the results of which led him to consider these forms as intermediate between the Phycomycetes and the Ascomycetes, placing them accordingly in a new group, the Hemiasci. He suggested in a footnote the possibility of Monascus belonging to it. Into this group the genus Monascus seemed to fit naturally, judging from Van Tieghem’s account. It was first definitely placed there by Schroter (19), who at the same time recognized that Harz’s genus Physomyces was identical with Monascus . The order Leptoomycetes was therefore re-named by him Monascaceae, and in it were included the two species, described by Van Tieghem, together with Physomyces heterosporus , re- named Monascus heterosporus , H el icosporangiu m , Kars, and Papulaspora , Preuss., the two latter genera being included on the authority of Harz. No new facts with regard to the genus were brought to light until 1895 , when Went published a paper on ‘ Le Champignon de l’Ang-quac ’ (27). Ang-quac is a deep purple colouring matter prepared in China, and used in Eastern Asia for cooking purposes as a pigment. It consists of coloured powdered rice, the colour being produced by a fungus growing on the rice. Went isolated this organism and found it to be a new species of Monascus , naming it M. purpureus because of its characteristic colour. In studying its life-history he found several new and important facts in connexion with the development of the ‘sporangium,’ which the previous authors had not mentioned. The first stage consisted in the formation at the end of a hypha of two branches or cells, the one straight and apparently the terminal cell of the hypha, and the other formed just below it and slightly curving around it. The latter in course of growth continued to curve more and more, until the two were bent almost at right angles to the parent hypha. Went called the curved cell the ascogenous hypha, and regarded the straight branch as the first investing hypha. The asco- genous hypha then became divided into three cells by the O 194 Barker .— The Morphology and Development of formation of transverse septa. The cell at the apex of the ascogenous hypha he called the terminal cell, the middle cell the sporangium, and the lower cell the pedicel. The latter proceeded to put out branches, which grew around the sporangium, completely enveloping it. At the same time, the sporangium itself was continually swelling up, reaching in some cases a diameter of 75 /x. The terminal cell and the first investing hypha were soon lost sight of, owing to the development of the other investing hyphae. During the en- largement of the sporangium its wall thickened and its proto-' plasmic contents passed through several striking changes. In the young sporangium the protoplasm contained several large vacuoles. These divided again and again until the protoplasm possessed a foam-like structure. Later it became very opaque, the vacuoles at the same time becoming ex- ceedingly small, so that the interior of the sporangium could not be clearly seen. In the end the contents divided up into a number of spores. The exact moment of the division could not be discovered. While usually the whole of the sporangium was filled with spores, instances were occasionally met with where spores were only to be found in one portion of the sporangium, the remainder being filled with vacuolated protoplasm. When the surface of the mass of spores was carefully examined, no interstitial material was found between the spores, the latter presenting an angular appearance. The number of spores was variable, some sporangia containing only 6-10, while others contained from 150 to 500. When the spores were first liberated they retained their angular appearance, but soon assumed an oval shape. In size they were about 5-6*5 jot. Conidia were also produced soon after the formation of the perithecia. They resembled those described by the earlier authors. With regard to the systematic position of the fungus, Went, on Van Tieghem’s authority, in the absence of the necessary literature placed it in the genus Monascus. He considered also that this genus ought to be placed among the Hemiasci, showing in par- ticular much resemblance to Thelebolus . He also discussed 195 the Ascocarp in Monascus . the significance of the first investing hypha mentioned above. From its position and period of development he considered that it showed certain correspondence with the antheridial branch of certain Ascomycetes, but, in view of the facts that it had not the constant structure of such organs and that its function, as far as he had observed it, was merely that of an investing hypha, he concluded that the relationship was not clear. He observed, however, that in certain cases a second perithecium was developed from it, thus resembling the sporangial formation in Rhizopus, and therefore suggested that it might be a rudimentary organ, the vestige of another sporangium, recalling the group of sporangia that is found in Rhizopus. The value of the ascogenous hypha seemed to him clear. The sporangium corresponded to the sporangium of the Mucorini in most instances, and the pedicel to the sporangial pedicel of the latter group. In those cases, however, where the sporangium contained but 8 spores, he considered that it approached the asci of the Erysipheae, and in particular the ascus of Sphaerotheca. In such cases the resemblance to the Erysipheae was so great that it might easily be mistaken for the perithecium of one of that group. Recently Uyeda ( 23 ) published a paper dealing with the fungus of ‘Beni-koji.’ This substance is used in the pre- paration ‘ Anchu,’ a fermented drink of Formosa. It consists of rice-grains infected with a pigment-producing fungus. The latter he found to be a species of Monascus. His results on the development and morphology of the ‘ sporangium * corresponded in essentials with those of Went. The size of the ‘sporangium’ was usually about 38-38*5 // in diameter, and the number of spores 30-40, the latter being oval in shape and S~ 6 ^ in length by 4-5 \x in width. A dark-red pigment was produced by the fungus. Micro- and macro-conidia and intercalary gemmae were also formed. Uyeda believed the species to be identical with Went’s Monascus pur pur eus. 196 Barker. — The Morphology and Development of The Systematic Position of Monascus. Before attempting to discuss this point, in view of the results described in this paper, it seems advisable to examine the possibility that the fungus examined by me may merely bear superficial resemblances to the species of Monascus described by other authors, belonging in reality to an altogether different type. Comparing it for the moment with M.purpureus , as described by Went, choosing this species on account of its more detailed description and illustration, the superficial resemblances between the two are extraordinarily pronounced, and, were not one in possession of the complete series of figures accompanying this paper, having instead in view merely such figures as Figs, ir, a-d\ 13, a ; 19, 33; representing inter- mediate and isolated stages, no hesitation would be felt in classing them together as members of the same genus or possibly even as identical Fungi. In each case the earliest stages of perithecial formation are represented by the forma- tion of two branches at the apex of a hypha, the one straight and obviously the terminal cell of the parent hypha, and the other arising immediately beneath and curving around it. Then follows the division of the curved branch, the ‘ascogoniunT as it has been termed above, by transverse septa into two (or, as Went has it, into three) cells, leaving out of account for the time being the fusion which Went did not observe. The difference in the number of cells into which the ascogonium is thus divided is not of importance at this point, seeing that occasionally I found that a septum is formed across the parent hypha a little below the ascogonium, thus cutting off a cell which acts in every way similarly to the * pedicel ’ cell of Went. After the division of the ascogonium by transverse septa the subsequent behaviour in both cases is for a time identical, this consisting in the swelling of the central or penultimate cell and the formation of investing hyphae from the ‘ pedicel ’ cell or the region of the parent hypha cor- responding to it. After the full development of the investing the Ascocarp in Monascus . 197 hyphae it is still possible in a few cases (see Fig. 19) to find a structure corresponding to that next described by Went, viz. a large sporangium-like cell invested by a wall of small hyphae. The resemblance then apparently would cease for a time were the two forms studied by series of microtome sections, owing to the formation of the internal hyphae as described above, although when viewed in the whole condition no difference would be seen. Finally, at the time of spore- formation the similarity of structure is again noticeable. The apparent angularity of the spores within the perithecium de- scribed by Went is very clearly to be seen in many cases, but I am convinced that the angularity is due to the optical effect of the arrangement of the spores under very high magnification. This can easily be verified by transverse sections in which the spores are then seen to be of the normal oval shape. The liberation of the spores is accomplished in each case by the breaking down of the perithecial walls. After this analysis of the similarity of the two forms at different phases of the development, it will be admitted that there are strong reasons for supposing that the fungus which I have described here is closely related to M. purpureus . It yet remains to be shown, however, how the account of the sporangial method of spore-formation can be reconciled with the account given above of the formation of the spores in asci. That the latter method is undoubtedly the one made use of by the ‘ Samsu ’ fungus is obvious, as the accompanying figures show. Is there any possibility that it may also occur in M. purpureus , and that the earlier authors have over- looked it? It has been shown earlier that the ripe perithecium bears an exceedingly strong resemblance to an invested sporangium. It has further been mentioned that the swelling of the central cell, the c sporangium ’ of previous authors, can be traced for some considerable period during the development of the investing hyphae, and also that its further behaviour, when watched in the living condition, is then lost sight of owing to difficulties of observation. This is also admitted by the 198 Barker . — The Morphology and Development of previous writers. It has also been stated that the subsequent stages, visible in the living condition, consist of an apparent conspicuous vacuolization of the protoplasm of the central cell, and eventually the formation of spores within it. We have seen that the apparent vacuolization is due to the formation of much entwined hyphae, produced and practically surrounded by the much enlarged and curiously-shaped central cell ; and that the spores are formed in small spherical asci arising from these internal hyphae. It has also been shown that these structures can only be seen at all clearly when the material has been suitably fixed and stained at all the different periods in the development of the perithecia. It would not be surprising, therefore, if the earlier observers had overlooked these facts. From what has been brought forward it seems probable that they did overlook them, and this is rendered fairly certain from their papers and figures. Considering Went’s paper first, it has already been noted that, when the investing hyphae had formed a more or less complete covering to the central cell or ‘ sporangium,’ the behaviour of the latter was obscured. In a few cases it was possible to observe changes in the protoplasmic contents of the ‘ sporangium,’ which first presented the appearance of containing large vacuoles, this stage being followed by a somewhat similar phase in which the vacuoles were smaller and the structure more foam-like, these features in the end becoming so pronounced as to render the internal structure indistinguishable, which continued until spores appeared. Although the author searched carefully he was not able to discover the exact period or method of spore-formation. His figures, which accompany the paper, include examples of all these stages. Bearing in mind the fact that he was dealing with living material, we notice that the apparent structures of the ‘ sporangium,’ which he has described, are in essentials identical with the stages observed above under similar con- ditions. But we have seen that the apparent vacuolization is really due to the formation of hyphal branches from the ‘ sporangium, ’ which organ has more or less surrounded them the Ascocarp in Monascus. 199 owing to the exigences of the structure of the perithecium. The early large vacuoles are the first-formed hyphae, and the later small vacuoles are the numerous branches of various sizes arising from these hyphae. The confusing optical features of the mass of entwined hyphae are responsible for the opaque appearance noticeable later, while Went’s failure to discern the moment and method of spore-formation is naturally due to the nature of the development of the spores in asci, they being under the surrounding conditions only clearly visible when fully formed. The apparent angularity of the spores, mentioned earlier, which gave rise to the idea that they were formed by cleavage of the protoplasm in the typical sporangial method of spore-formation — see Harper ( 11 ) — is, as already pointed out, merely an optical effect. But apart from Went’s description his figures are sufficient to confirm the statements just made. His Figures 17 and 18 are practically identical with Figures 1 3, a , b , of this paper. Perhaps, however, the most convincing proof is that which may be deduced from his statement that in some of the ‘ sporangia’ he found spores in only one region, the remainder consisting of bands of protoplasm and vacuoles. Here it is clear that he had to deal with perithecia, in which the asci were not distributed throughout, but were grouped in one portion. The nature of the protoplasmic bands and vacuoles is obvious from the preceding. Thus we find that Went’s account is based on a misinter- pretation of the observed facts, and that M. purpureus in all probability is a true Ascomycete with a perithecial formation similar to that of the ‘Samsu’ fungus. Owing to the suggested identity between M. purpureus and the ‘Beni-koji’ fungus it is necessary to examine Uyeda’s results to see if any fresh evidence is forthcoming in favour of the 1 sporangium ’ view. It has been seen that this ob- server’s results agreed entirely with those of Went. He gives, however, two figures (Figs. 9 and 10) which may be taken as representing stages not figured by Went, his insufficient description rendering it uncertain if they merely reproduce 200 Barker .— The Morphology and Development of the stages figured by Went in the latter’s Figs. 20 and 22. Uyeda’s Fig. 9 represents a section through a developing perithecium, showing a large 'sporangium’ surrounded by a wall of hyphae. The S sporangium ’ is undivided and filled with granular protoplasm. Apart from any question as to whether any ‘ internal hyphae ’ have been overlooked in this preparation, it may represent the stage shown in Fig. 19 of this paper, or it may represent a section through an older perithecium, in which none of the ‘ internal hyphae ’ have been included, a portion of the swollen central cell with its investment of hyphae being merely shown. Fig. 10 of this observer represents a section through a perithecium, similar in size to the preceding, but having the ‘ sporangium ’ com- pletely divided into more or less angular areas. This, I suppose, represents the division of the protoplasm of the sporangium into spores, and may correspond to the stage which I have described above, where the ripe spores freed from the degenerated asci are lying within the perithecium and appear to be arranged in angular areas: but, judging from the figure, it probably represents the stage where the perithecium is entirely filled with dense entwined hyphae, shortly before the formation of the asci. There is then nothing in Uyeda’s paper to lead one to suppose that the ‘ Beni-koji ’ fungus differs in any way from M. purpureus , and thus from the - Samsu’ fungus, in the nature and method of development of its perithecia. Considering now Harz’s paper on Physomyces heterosporus , seeing how closely his account of the structure and develop- ment of the ‘ sporangia 5 corresponds with the accounts given by Went and Uyeda for M. purpureus , it seems hardly necessary here to recount in detail the reasons for supposing that he was really dealing with a form of Monascus. It is true that he did not describe the earliest stages of perithecial formation in much detail, and that consequently no com- parisons can be made as to the method of division of the ascogonial filament. But he stated that the earliest stages were represented by the formation of two or three small hyphae at the apex of a branch of the mycelium, and that the A scocarp in Monascus. 201 around these other hyphae springing from their bases were developed, so as to invest them. In the latter stages he gave a figure (Fig. 7) corresponding to Uyeda’s Fig. 10, to which the same arguments can be applied as have been already given for the latter. It may then fairly be concluded that Harz’s Physomyces heterosporus , or, as Schroter named it, Monascus heterosporus , forms its perithecia in the same manner as M. purpureus. With regard to the two species described by Van Tieghem, M. ruber and M. mucoroides , there is not a great deal to be said. We have this observer’s authority for considering M. purpureus as a member of the same genus, and from this fact it might be deduced that he had fallen into the same error as the subsequent authors. There is not the same amount of evidence at hand, however, since no figures accompany his paper. It is of course quite possible that the Fungi described by him possess the structure which he attributed to them, but, in view of the subsequent errors in connexion with apparently similar forms, one has considerable reason for concluding that these two species are allied to the ‘ Samsu ’ fungus. Having now examined the relationships of these various forms to one another, and having seen that there are the strongest grounds for regarding them as members of a single genus, there remains yet another point to be discussed before the characters of this genus are set forth. It concerns the behaviour and function of the structure which has been termed above the ‘antheridial branch.’ It has been shown that a fusion occurs between this organ and the ascogonium, preceding the development of the latter with its subsidiary structures into the perithecium, and that this fusion is probably accompanied by a passage of nuclei from the former into the latter, and subsequent nuclear fusion in the latter : in other words, that a sexual act takes place between the antheridium and the ascogonium. Harz and Van Tieghem have not described any definite organ corre- sponding to the antheridial branch, doubtless having observed it and regarded it as one of the first-formed investing hyphae. 202 Barker . — The Morphology and Development of Went and Uyeda, however, have seen and described it ; and, although the former pointed out its similarity to the antheridium of certain Ascomycetes, he failed to discover the fusion between it and the ascogonium, and suggested instead that it might be a rudimentary organ, the vestige of another sporangium. Both considered that in the present case it served as nothing more than the primary investing hypha. It seems likely that these observers have overlooked the fusion. It has been seen that the fusion is almost invisible at the time of its occurrence even under the highest powers of magnification, except in rare instances. At the time when it becomes visible, i. e. when the central cell has become much enlarged and the investing hyphae formed, they seem to have lost sight of the structure. In fact, Went stated that it was hidden by the other hyphae. These reasons, together with the significance of its constant occurrence, its time of formation, and its position, warrant us in regarding it as a true antheridial branch, and in believing that, apart from a few possible exceptional cases, in which the ascogonium may develop further parthengentially, fusion takes place between it and the latter organ. There can be no doubt in view of Went’s discussion of its significance that this author would have regarded it as an antheridium, had he observed the fusion. A minor point of interest is that which concerns the division of the ascogonium after fertilization. Both Went and Uyeda found that it became divided into three cells — the terminal cell, the ‘ sporangium/ and the pedicel. From the latter the investing hyphae arose. In the ‘ Samsu ’ fungus, on the other hand, only two cells are formed — the terminal cell, which includes the place of fusion, and the central cell, corresponding to the ‘ sporangium.’ The investing hyphae arise from the region of the present hypha immediately below the latter. From the figures of these authors I have no reason to suppose that their account of the origin of the pedicel is not generally correct. Its size and position certainly appear to the A sco carp in Monascus. 203 bear out their statement that it is cut off from the asco- gonium. As stated above, I have found occasionally a cell cut off below the ascogonium which behaves in the same way as their pedicel, but it is merely a cell cut off immediately below the ascogonium, and has not constituted a portion of that organ. It is also not so conspicuous as their pedicel. In one or two instances figured by Went, however, his ‘ pedicel ’ cannot have the origin ascribed to it, and is in those cases nothing more than the cell of the parent hypha im- mediately below the ascogonium. If their accounts be taken as correct for the majority of cases at least, we have in M. purpureus to deal with a more specialized form of perithecium than in the ‘ Samsu ’ fungus, a point which at once separates the two forms into different species ; whereas if their * pedicel ’ has really an origin similar to that in the somewhat rare instances just quoted, it is highly probable that the two Fungi are members of the same species. Since they have not given figures of the successive stages in the development of a single perithecium, such as could be obtained by observations of hanging-drop cultures, it is im- possible to make a more definite statement as to the identity of the forms. We are now in a position to state in detail the characters of the genus Monascus. The mycelium consists of much-branched, septate hyphae, which produce at certain periods two kinds, at least, of repro- ductive organs. The asexual organs are usually spherical or ovoid bodies, formed as a rule basipetally at the ends of branch hyphae in chains of varying lengths. They are usually colourless, but, after the formation of pigment has begun in the mycelium, they may be slightly tinged with the corre- sponding colour. Sexual reproduction results in the forma- tion of ascogenous hyphae. An archicarp, consisting of an ascogonial branch and an antheridial branch, is formed usually at the end of a hypha, the former arising immediately below the latter and proceeding to grow above and around it. Both are cut off into distinct organs from the parent hypha by the 204 Barker . — The Morphology and Development of formation of septa, the antheridial branch being usually the former apex of the parent hypha. Fusion then takes place between the two organs, followed probably by migration of nuclei from the antheridium into the ascogonium and sub- sequent fusion of these with the nuclei of the latter. The fertilized ascogonium then divides into a terminal cell and a central cell by the formation of a transverse septum, and possibly in some instances a third cell, the pedicel, is also cut off. The central cell begins to swell considerably, and becomes invested by hyphae, arising immediately beneath it, either from the parent branch or from the pedicel, when the latter is present. After swelling, the invested central cell produces one or more hyphae which develop vigorously and produce a mass of entangled ascogenous hyphae, which displace it to a certain extent, causing it to completely envelop them and to become closely adpressed to the enclosing investing hyphae. The latter soon become much flattened out and lose their contents, being represented in the later stages by a mere reticulum of brown cell-walls around the enlarged central cell. Asci are eventually produced from the asco- genous hyphae, and in each of them eight ascospores are usually formed. When the spores are ripe, the asci and asco- genous branches degenerate, the surrounding central cell having by this time lost its contents, remaining as a brown cuticularized enclosing wall. The spores are thus liberated into the cavity enclosed by this wall, and the ripe perithecium appears to be nothing more than a brown cuticularized sporangium-like structure. From it the spores escape by the degeneration of its walls. The number of spores is very variable. They are spherical or ovoid in shape, and possess thick walls. They are more or less red, brown, or orange in colour, and possess a very characteristic refringent appearance. From this description it follows that the genus must be placed among the Ascomycetes. At the same time it does not very clearly fall into any well-defined group on account of the curious behaviour of the central cell and the incomplete character of its investment. At various stages of its develop- the Ascocarp in Monascus. 205 ment it presents interesting resemblances to several types. Unfortunately there are but few instances in which the development of the ascocarp has been followed step by step from the earliest stages, so that the range of comparison is very limited. The archicarp is strikingly similar to the archicarp of cer- tain species of Peziza , e. g. Peziza scutellata as described by Woronin (29) : and in those instances in which the ascogonium curves spirally around the straight antheridial branch it recalls the archicarp of Penicillium — see Brefeld (3) — and many Gymnoascaceae. The young perithecia resemble the young perithecia of Sphaeria Lemaneae and Sordaria coprophila (30), and the similarity between the enlarged ascogonium of these forms and the developing central cell may also be pointed out. If the development of asci were to occur in the young perithecia of these forms, an ascocarp almost identical in structure with that of Monascus would result. The mature perithecium with spore-containing asci is some- what similar in structure to those of the Aspergillaceae and the multi-ascal Erysipheae. None of the Fungi just mentioned can be classed with it throughout the complete course of the development of the perithecium, the Pezizineae and the Sphaeriales separating themselves by the structure of the mature perithecium, and the Erysipheae and Plectascineae by the method of develop- ment of the ascogonium after fertilization. Its points of resemblance to so many widely separated groups of Ascomycetes are of particular interest when viewed in conjunction with the fact of the undoubted simplicity of the ascocarp in structure and development. There are several features which indicate the simplicity of the genus. One of the most noticeable is the want of dif- ferentiation and of specialization of the antheridial branch and the ascogonium, shown in so many anomalous cases. Under certain conditions any living cell of any hypha of the mycelium seems to be able to take on the functions of an antheridium, and the cell immediately beneath it to produce 206 Barker . — 7 "^ Morphology and Development of the ascogonium in the normal manner, further development taking place quite normally. Often, too, a normally produced antheridium, after functioning as such, proceeds to develop ordinary vegetative hyphae or conidia ; while, less often, even the ascogonium or, more accurately, the terminal cell of the ascogonium behaves similarly. There is thus shown a want of constancy in the position of development and in the specialization of the sexual organs which seems to point to their primitive nature, as compared with the more strongly defined archicarps of other Ascomycetes. The mature ascocarp is also in reality of very simple structure. While apparently a cleistocarp, as in theErysipheae, it is actually only of that nature because of the curious development of the central cell. The exterior investment of hyphae is very incomplete and scanty, and the whole of the hyphae within the ascocarp are ascogenous and arise from the fertilized ascogonium. The extent of the development of the ascogenous hyphae themselves is also very small, speaking comparatively, and variable, and the same holds good for the number of asci. The sexuality of the archicarp is also little developed. The male and female organs arise not only from the same hypha, but also from the same cell of it, and therefore pro- bably the male and female nuclei have their origin from the same nucleus or nuclei with the intervention of but few generations. The method of reproduction by conidia is also very simple. No specialized conidiophores are developed, any hypha being capable of producing conidia, these being formed simply by the formation of a wall just behind the apex of the hypha and the swelling of the terminal cell thus cut off. The primitive nature of the ascocarp has just been men- tioned. Leaving out of account the complexity introduced by the behaviour of the enlarged central cell, it is clear that the asci must be regarded as being devoid of a complete investment of sterile hyphae. The comparatively feeble development of investing hyphae would be quite insufficient the Ascocarp in Mon asciis. 207 to enclose the asci without the aid of the central cell. Viewed from this point of view, the ascocarp seems to be of the same nature as those of the Gymnoascaceae. A re- lationship to this group is also indicated by the shape, size, and method of development of the asci, and by the number and size of the ascospores. The archicarp is also very similar to that of Gymnoascus Reessii. In both forms the antheri- dium is typically a short straight hypha around which is coiled more or less the ascogonium. Fusion takes place between these organs, and the ascogonium subsequently develops further by producing a short branch, which gives rise to the ascogenous hyphae 1 . While these facts point to a relationship to the Gymnoas- caceae, there are certain features which are opposed to the idea of a very close connexion with this group. In the first place the investing hyphae of Monascus are only partially comparable to those of the Gymnoascaceae. In the former they arise from a definite point, i. e. immediately below the central cell ; in the latter this is not so markedly the case. In the former also they grow closely applied to the ascogonium, resembling rather the earliest sterile hyphae of the ascocarps of the Aspergillaceae, Erysipheae, Sphaeriales, and Pezizineae ; while in the latter the investment as a whole is of a compara- tively loose character. Attention may here, however, be called to the curious development of small branched clasp- like hyphae from the hyphae bearing the archicarp, at some distance below this structure (see Fig. 14), and even in some cases from neighbouring hyphae. They may serve to show a possible connexion between the investments in the cases under consideration. A second difficulty is the nature of the ascogonium. In Monascus , although filamentous when first formed, after fertilization it swells considerably, becoming more or less spherical before the production of ascogenous hyphae. In the Gymnoascaceae it remains unchanged through- out ; in some cases, e.g. in Ctenomyces serratus and Gymnoascus 1 I have obtained the facts concerning Gymnoascus from Miss Dale, whose paper on the subject has not yet been published. 208 Barker . — The Morphology and Development of Candidas , dividing into several cells, from which the ascogenous hyphae spring, and in other cases, e. g. in Gymnoascus Reessii, growing directly out into a branch, from which the ascogenous hyphae arise. The ascogonium of Monascus therefore resem- bles the enlarged more or less spherical ascogonia of the Sphaeriales and Pezizineae much more than those of the Gymnoascaceae. While these considerations tend to place it outside the Gymnoascaceae, there is nevertheless no other group of Asco- mycetes in which it could be placed. From the lower genera, such as Endomyces , Eremascus , Exoascus , and Ascocorticum , it is at once distinguished by the formation of an ascocarp. From the Pyrenomycetes, Discomycetes and the higher Plectascineae it is distinguished by the relatively simple ascocarp. Of the Fungi just mentioned the ripe ascocarps of the Aspergillaceae and the Erysipheae appear from a surface view to resemble strongly those of Monascus . Their internal structure is also very similar, if compared with the latter at the stage when the central cell is indistinguishable from the cutinized investing hyphae and the interior is filled with a mass of tangled hyphae and asci. The study of the method of development in each case shows, however, that this similarity in structure is of no value as indicating a close relationship between these forms. The whole of the structures within the ascocarp of Monascus have their origin from the ascogonium, and are of the nature of ascogenous hyphae and asci. In the other forms sterile hyphae not of ascogonial origin are mingled with the ascogenous hyphae and asci. There is a certain amount of similarity also between the archicarps of these forms. Very little is known about these structures in the Aspergillaceae, but the resemblance shown by that of Penicillium has already been mentioned. In this case, however, it has not yet been shown that fusion takes place between the sexual organs. The ascogonium moreover the Ascocarp in Monascus . 209 divides into several cells, from each of which ascogenous hyphae arise. In the Erysipheae the ascogonium and antheridium arise from different hyphae. Otherwise they are very much like those of Monascus. The ascogonium, however, divides into several cells after fertilization, some or all of which produce asci. The points of resemblance shown by the other Ascomycetes are confined to the archicarp and the earliest stages in the development of the ascocarp. The mature ascocarp of these forms, whether of the Discomycetous or Pyrenomycetous type, is a much more complicated and highly developed structure. The archicarp of Peziza scutellata has already been referred to. Woronin &(29), who has described it, found that the terminal cell of a short hyphal branch became somewhat enlarged, while from the cell immediately beneath it a small hypha was developed which grew around the former, be- coming closely applied to it. He surmised that the former was the ‘ egg-cell 5 or ascogonium, and the latter the antheri- dium. The behaviour of the two structures was soon obscured by the development of investing hyphae, a perithecium eventually resulting. There is thus very little direct evidence to warrant the assumption that they represent sexual organs or that they retain their sexual functions : but in view, in particular, of Harper’s work on Pyronema (10) and the Erysipheae (9), and also of the results of other observers, all of which tend to show that the archicarp is an organ of a sexual nature, although perhaps not necessarily always functional, to which the ascocarp owes its origin, these structures described by Woronin become invested with considerable significance and can fairly be looked upon as constituting an archicarp. If the enlarged cell be regarded then as an ascogonium and the smaller hypha arising immediately beneath it be taken as an antheridial branch, the similarity to the corresponding structures of Monascus is very pronounced, since in both cases they are developed in close contact at the apex of a short branch. It is true that in the former case the antheri- P 210 Barker . — The Morphology and Development of dial branch arises below the ascogonium, whereas i w Monascus it forms the apex of the branch, the ascogonium being deve- loped beneath by the formation of a new growing-point at that spot. This difference, however, is probably of no great importance, since it is merely a matter of the time of develop- ment. Where two or more structures are formed at the end of a hypha, it is the first-formed which appears to constitute the apex of the branch, and the others appear to arise below it. In reality, however, they are all terminal. It is thus with the cases in point, and in both instances eventually the asco- gonium by its superior development assumes the apical position, the antheridial branch appearing to arise below it, although in Monascus the latter was really first formed. Of the subsequent development of the ascocarp from the archicarp in Peziza scutellata we have insufficient details for further comparison. Fortunately, however, the complete series of changes in the case of Pyronema confluens , a member of the same group, is available for comparison owing to the successful and complete work of Harper (10). This fungus differs from the former in having the anthe- ridia and ascogonia developed on different hyphae. A slender filamentous hypha, the trichogyne, is formed as an outgrowth from the ascogonium, and fusion takes place at its tip between this and an antheridium. Nuclei then pass from the latter through the trichogyne into the ascogonium and there fuse with the nuclei of that organ. A wall is then formed cutting off the ascogonium from the trichogyne. The nuclear fusions take place during a period in which the nuclei are aggregated closely together towards the centre of the ascogonium, the outer portion of which is for the time being almost devoid of nuclei. While these processes are occurring, the neighbouring hyphae branch freely and form a close investment around the ascogonium, or rather, since these organs are usually pro- duced in rosettes or groups, around the whole group. The ascogonium then produces numerous outgrowths, which grow out between the investing hyphae and form the ascogenous hyphae. These eventually arrange themselves in a more or 2 1 I the A sc ocarp in Monascus. less definite layer, intermingled with and surrounded by the sterile hyphae, and eventually produce at their tips the elon- gated asci, the whole fructification having by this time assumed the characteristic cup like form. Comparing it with Monascus , the main point of difference from the latter is the occurrence of the sexual organs on distinct hyphae, which necessitates the formation of a tricho- gyne. The fusion between this and the antheridium corre- sponds with the fusion between the tip of the ascogonium and the antheridial branch in Monascus . The passage of male nuclei then takes place in both cases, followed also by the aggregation of the mixed sexual nuclei in the ascogonium. In both cases also the ascogonium is cut off from the antheridium by the formation of a wall ; in the case of Pyro- nema at the base of the trichogyne, and in the case of Monascus across the ascogonium just behind the place of fusion. The apical portion, i. e. the terminal cell, of the ascogonium in Monascus may be therefore considered as equivalent to the trichogyne of Pyronema. The nature of the fusion in both cases is very similar. The fusion is in no way complete as is the case, for example, where two hyphae fuse to form a zygospore. The two fusing structures maintain their individuality, and the opening between them is no more than a small pore, just sufficiently large enough to allow of the passage of nuclei. During the period of nuclear aggregation in Pyronema the fusions between the sexual nuclei occur. The occurrence of a similar period in Monascus makes it seem likely that the sexual nuclear fusions, which almost undoubtedly occur, take place during that time. At the end of this stage the asco- gonium in each instance puts out one or more branches, the ascogenous hyphae, which ramify to a greater or less extent and eventually produce asci. The investing hyphae in Pyro- nema are much more strongly developed than in Monascus , but in both cases the ascogonium itself is closely invested, differing in this point from the Gymnoascaceae. Thus, although Pyronema confluens differs from Monascus 212 Barker.— The Morphology and Development of so considerably in the structure of the archicarp and of the mature ascocarp, the processes leading to the formation of the latter correspond very closely in the two forms and suggest a common origin : and if the cytological behaviour of the former is characteristic of the other Pezizineae, Peziza scutel - lata is still more closely allied on account of its simpler archicarp. The Sphaeriales also seem to be allied in a somewhat similar manner. Woronin (30) has described structures in Sphaeria Lemaneae and Sordaria fimiseda which must be regarded as the archicarps of these forms. The ascogonium is an enlarged spherical cell, to which is closely applied a smaller hypha, arising in the former from another and in the latter from the same branch of the mycelium, which seems to be the antheridial branch. Around these numerous coiled hyphae arising from the neighbouring portions of the myce- lium grow closely applied, and a small spherical mass is thus formed. By the further development of this the characteristic perithecia are produced. The behaviour of the archicarp during this development is unknown, but it is surmised by analogy with Pyronema and other forms that it corresponds to a certain degree with these. If this be the case, the rela- tionship suggested between the latter and Monascus would also hold good for them and other Sphaeriales. These considerations point to the view that Monascus repre- sents a low and comparatively simple type of Ascomycete and is not far removed from a common ancestral type, from which all the higher Ascomycetes may be supposed to have sprung. The latter are separated into distinct families by the structure of the mature ascocarp only, and there seems to be no essential difference in the nature of the reproductive organs themselves. The discovery of the archicarp or of vestiges of this structure in members of the different groups seems to indicate that the ancestral Ascomycetes possessed functional sexual organs, the ascogonium and the antheridium, the fertilization of the former by the latter resulting in the development of asci by the formation of a more or less complicated system of asco- the Ascocarp in Monastics, 213 genous branches from the former. The sterile hyphae, which form the investing hyphae and contribute so largely to the actual vegetative portion of the ascocarp in the higher Ascomycetes, may be regarded as a secondary development, affording the ascogenous hyphae a better opportunity of pro- ducing asci successfully ; and it is the form taken by their development which determines the form of the mature asco- carp, and therefore serves to create the distinctions which characterize the various families. In Monascus we have a form that approaches very nearly this supposed ancestral type. It possesses antheridia and ascogonia which are fully functional, though simple in type and not highly differen- tiated, being in fact typical of a primitive form. The investing hyphae, moreover, are very subordinate, the investment being rudimentary as compared with those of the higher Ascomy- cetes, while the formation of subsidiary clasping hyphae (see Fig. 14) on the lower part of the hypha bearing the archi- carp and on the neighbouring hyphae may be considered as a primitive form of the much more highly developed invest- ment of the other types. It may be urged that these structures are vestiges, and that the fungus is a much reduced form, but the complete retention of sexuality together with the feebly differentiated nature of the sexual organs seems to be entirely opposed to this idea. The gap which separates Monascus from the supposed ancestral type is small. The distinguishing features are the occurrence of investing hyphae and the envelopment of the ascogenous hyphae and asci by the enlarged central cell. An explanation of the development of these features may perhaps be arrived at by a consideration of their probable functions. The investing hyphae in the higher Ascomycetes undoubtedly serve to protect the ascogenous hyphae and also the ascogonium, while producing them. This function also seems to be exercised by them in the case of Monascus , although by the nature of the structure only the ascogonium is directly protected, and that incompletely. The cutinization of their walls in the later stages of the development of the 214 Barker . — The Morphology and Development of ascocarp, and the manner of their arrangement around the central cell, certainly serve however to maintain the developing asci in a position of security within the cavity of the perithe- cium. Another possible function is suggested by the analogy of the investing hyphae to the auxiliary cells of the Florideae, a relationship of the Ascomycetes to this group having been considered likely by many authors. The function of the auxiliary cells seems to be that of supplying nourishment to the growing sporogenous ooblastema filaments. The investing hyphae may therefore serve to supply nutrient material to the developing central cell, and thus indirectly to the ascogenous hyphae, although no fusion takes place between them and the central cell as is the case between the ooblastema filaments and the auxiliary cells. The close application of the investing hyphae to the central cell doubt- less renders fusion unnecessary. If these are the functions of the investing hyphae generally among the higher Ascomycetes, and in a correspondingly less degree among the lower forms in which these structures are not so well developed, one would expect to find them per- formed in the latter instances to some extent by the asco- gonium itself. The peculiar shape taken by the developing central cell in Monascits has already been mentioned above on several occasions. A little consideration shows that this shape is the one most suited to carry out the combined functions of protection and nutrition for the growing asco- genous hyphae. The protective function is undoubtedly utilized, for after it has shrunken and its walls have become cutinized the young asci are completely enclosed in the resistent envelope thus produced by it. It exercises naturally a nutritive function, since the ascogenous hyphae arise directly from it. But this is exerted in an increased degree by the method of arrangement of these hyphae in relation to it. They are so arranged that they are in close contact with it from the moment of development, and the young vigorously growing tips appear to actually press into it, the cavity eventually becoming enlarged by this means. With such the Ascocarp in Monascus, 215 close contact the transference of nourishment from the central cell can be carried out with much greater ease than by its passage from that organ through the whole length of the ascogenous hyphae to the growing-points. Of course in the older perithecia such close contact no longer obtains, the hyphae themselves forming a somewhat considerable mass, but it is noticeable that at comparatively late stages the central cavity seems still to owe its enlargement to the burrowing of the youngest hyphae into the central cell. An adequate explanation is thus furnished of a unique and mysterious perithecial structure. This view explains why the first formed ascogenous hyphae do not grow out through the gaps in the reticulum of investing hyphae, but remain closely attached to and hollowing out the central cell. This most important point is apparently inexplicable except by the hypothesis just suggested ; and thus fresh emphasis is laid upon the already well recognized idea that asci can only be formed by young and vigorous hyphae, which moreover can only be raised to and maintained in that condition by an abundant supply of nutriment. Perhaps some light is thrown on the nature of the required nutriment in this instance. The ascocarps are by no means always formed on aerial branches : indeed they are often completely submerged in the culture medium. When the food supply in this begins to get low, the formation of ascocarps begins. If it be the ordinary form of food that is required to keep the ascogenous hyphae in a sufficiently vigorous condition, why do they not grow out into the surrounding medium and obtain the avail- able food, instead of trusting to the more difficult mode of supply from the central cell? It seems as if the required nutriment is a substance or substances, manufactured by the fungus from the raw food material supplied by the sub- stratum. The view put forward here, then, is that Monascus is a simple sexual Ascomycete, showing the relationships to the higher forms that may be expected to exist between lowly and highly organized genera of common origin, and at the 2i6 Barker . — The Morphology and Development of same time presenting but few features to distinguish it from the supposed ancestral types, these being, moreover, such as serve for a more successful production of ascospores. General Considerations. There arise in connexion with this view two questions which must be considered. Firstly, in what relation does Monascus , as representing a type not far removed from the ancestral type, stand to the lower Ascomycetes? And secondly, does Monascus for the same reason afford any indication of the origin of the Asco- mycetes from the lower Fungi or from the Algae? These questions can perhaps best be dealt with in conjunc- tion. The nature of the sexual organs suggests at once a con- nexion with the Oomycetes, an idea already familiar through the theory of De Bary (5) as to the relationship of the various groups of Fungi. The antheridia and oogonia of this group correspond very well with the antheridial branch and asco- gonium of the archicarp of Monascus. Although in most forms the sexual organs are produced on different branches, yet in some cases, e.g. most Saprolegniaceae, they are borne on the same branch, the antheridia arising immediately below the oogonia. Fertilization takes place in most cases, the antheridium becoming closely applied to the oogonium and sending into it a tube which penetrates through the periplasm and then empties the contents, in whole or in part, of the antheridium in the neighbourhood of the oosphere. After fusion of the sexual gametes, the fertilized oospore becomes invested with a thick resistant wall, to the formation of which the periplasm contributes largely. After a period of rest the oospore germinates ; in some cases, e. g. Albugo Candida , pro- ducing zoospores directly, i. e. becoming converted directly into a zoosporangium; in other cases, e.g. Phytophthora omni- vora ) De Bary (6), forming a short promycelium, which pro- duces a few conidia, the contents of each of which divide into eight zoospores ; and in many other cases forming the ordinary the Ascocarp in Monascus. 217 mycelium of the fungus, on which conidia, or zoosporangia, and sexual organs are formed. An alternation of generations is thus presented by the life-history of some of these Fungi. In every instance the ordinary mycelium of the plant repre- sents the gametophyte, while the sporophyte is represented in such forms as Phytophthora omnivor a , De Bary, by the promycelium, and in such forms as Albugo Candida by the oospore itself, being unrepresented in the third case quoted above. Owing to the great diversity in behaviour shown by the members of the group from the period of fertilization onwards, it is difficult to select one particular form as a type for comparison with Monascus ; but there can be no doubt of the relationship of the various members of the group to one another, and therefore a general comparison will serve. Starting with the formation of the sexual organs, the first point of difference is the formation of a special egg-cell or cells in the Oomycetes, no differentiation of such a structure being apparent in Monascus . Some or all of the nuclei of the ascogonium of the latter are, however, in all probability fertilized by the male nuclei, and these may hence be regarded as functionally similar, although apparently undifferentiated. The papilla of the antheridium of the former group, which penetrates through the periplasm of the oogonium to fertilize the oospheres, has perhaps its analogue in the small papilla produced by the antheridium of Monascus at the time of fusion between this organ and the ascogonium. The different degree of development in the two cases may be due to the fact that in the former the oospheres are specially rounded distinct bodies lying within the periplasm, and therefore not so easily reached by the male elements as the female nuclei of the latter, distributed evenly in the undifferentiated proto- plasm of the ascogonium. After fusion in Monascus a special fertilized cell, the central cell, is cut out of the ascogonium, 1 the term ‘ fertilized cell ’ being here used in the sense described by Harper (10) for the corresponding structure in Pyronema , and it is then equivalent to the oospores of the former. Instead, however, of becoming clothed with a specially 2 1 8 Barker . — The Morphology and Development of thickened wall and passing through a long period of rest, as is the case with them, it proceeds at once to swell up con- siderably and produce ascogenous hyphae. This process must be regarded as the germination of the fertilized ‘cell’ and the beginning of the sporophyte generation : and there- fore corresponds with the germination of the oospore and the production of the promycelium of such a form as Phytophthora omnivora De Bary. The generation of the sporophyte is terminated in the one case by the formation of ascospores in asci, and in the other case by the formation of zoospores in sporangia. The germination of these spores in the respec- tive instances gives rise to the gametophyte. A difference is shown in the time of germination ; the zoospores, which are naked masses of protoplasm, germinating immediately after coming to rest and clothing themselves with a cell- wall, while the ascospores, which are thick-walled resistant bodies, are specially prepared to pass through a period of rest during unfavourable external conditions before germination at a suitable time. Thus the functions of the oospores are not assumed by the fertilized 4 central cell, 5 but are passed on to the ascospores. The shifting of the period of the resting stage of the organism here indicated suffices to explain the differences of organization of the female ‘ cells ’ in the respec- tive cases, and renders the parallel behaviour of the respective Fungi as regards the course of their life histories much closer than appears structurally. Leaving out of the question the differences which may be taken as arising naturally from the delegation of the function of hibernating to different structures in the two cases, there is a remarkable degree of resemblance in the manner and the course of the reproductive processes of these Fungi, so widely different in habit and in the structure of the mycelium. It is certainly sufficiently marked to make the idea of relationship likely. A further point of resemblance between Monascus and the Oomycetes is the nuclear behaviour during the reproductive processes. It has been shown that in Monascus several nuclei from the antheridium probably pass into the ascogonium and 219 the A scocarp in Monascus. there fuse in pairs with female nuclei as in Pyronema . Probably also there is an excess of female nuclei in the ascogonium, which remain unfertilized and eventually degenerate. The nuclei which remain in the terminal cell after the cutting off of the central cell can certainly be regarded in this light, and perhaps, too, some of the nuclei enclosed in the central cell come under this heading. Stevens has shown that in Albugo Bliti (20) and Alfoigo Portulacae (21) numerous male nuclei pass into the oogonium and fuse in pairs with female nuclei, while other nuclei of the oogonium remain unfertilized in the periplasm. It is therefore necessary to examine more closely the details of these various features to determine, if possible, whether it is merely a case of parallel behaviour or whether a definite relationship is indicated. The members of the Oomycetes which show a marked alternation of generations by the formation of a promycelium, e. g. Phytophthora omnivor a, De Bary, and Pythium proliferum (6), are those which approach most nearly the simple sexual Ascomycetous type, of which Monascus is an example. In the above parallel the ascus of the latter is equivalent to the zoosporangium of the sporophyte generations of Phytophthora and Pythium. From a type similar to these forms the Ascomycetous type represented by Monascus could be derived by the suppression of the differentiated oospore stages and the transference of its hibernating function to the zoosporangia of the sporophyte, these structures becoming much more definite, owing to the acquirement of that function, and producing only a small limited number of resistant spores. Among the difficulties standing in the way of the acceptance of this hypo- thesis are the difference of the mycelium in the two instances, the lack of differentiation of the zoosporangia of the sporophyte from those of the gametophyte, the different methods of spore- formation in sporangia and asci, and the lack of intermediate forms. Considering these in turn, the difference of the mycelia consists in the absence of septa, except in the reproductive 220 Barker . — The Morphology and Development of organs, in the Oomycetes and their presence in Monascus . The cells of the latter are, however, multinucleate ; consequently the mycelium cannot be looked upon as very highly different- iated. Other Ascomycetes, e. g. Erysiphe , moreover, possess mycelia consisting chiefly of uninucleate cells. Others, e. g. Exoascus ) have very much reduced mycelia. There is thus shown in the group of Ascomycetes itself a difference in the character of the mycelium at least as great as that between the two cases that are being considered. The apparent similarity of the zoosporangia of the sporo- phyte and gametophyte of Phytophthora omnivor a seems to make the ascus, which belongs clearly to the sporophyte, equivalent to a typically gametophytic structure. If, however, in this species the promycelium is regarded as an elementary form of sporophyte — and it has been viewed thus in the present discussion — there is a theoretical difference between the zoo- sporangia produced by it and those produced by the gameto- phyte. The delegation of the special functions of the ascus to the former would cause also a morphological distinction, so that the ascus is strictly comparable only to them. The others have their analogues in the conidia of the Ascomycetes, for both are products of the gametophyte, and among the Oomycetes conidia and zoosporangia are homologous. Harper (11) has pointed out the difference in the methods of spore- formation by cell-division in sporangia and asci. In the former the protoplasm divides directly by simple fission ; in the latter a gradual aggregation of the protoplasm around each nucleus occurs. In the sporangium there is thus no epiplasm, while in the ascus it is always produced. He regards these facts as showing that there is no genetic relationship between sporangia and asci. Since the zoospores of a zoosporangium are formed by the fission method, the same objection may be raised against the homology of this type of sporangium also with the ascus. Juel (15), however, believes that the gap between the Phy- comycetes and the Ascomycetes is not so wide as indicated by Harper’s results, owing to the presence of periplasm in the oogonia of the Peronosporaceae, the process of the formation the Ascocarp in Mona sens. 221 of the oospheres affording a link between the processes typical of spore-formation in sporangia and asci. It is true that it may be urged against this view that the oogonium is not homologous with the ascus or with the sporangium, and that if the two latter structures be regarded as truly homologous the gap between them remains therefore as wide as before ; but it is certainly shown that in some Oomycetes there exists a method of spore-formation, although not occurring in homologous structures, which is to some extent intermediate. Stevens (21) has shown that in Albugo Bliti , A. Portulacae and A. Ti'agopogonis the method of formation of the oosphere in the oogonium is as follows : — The protoplasm of this organ becomes much vacuolated, clumps of denser protoplasm being distributed irregularly among the more vacuolated substance. These clumps increase in size by fusion, and eventually a single dense mass, the gcnoplasm of De Bary, is formed in the centre of the oogonium surrounded by the vacuolated periplasm. The nuclei are at this stage arranged in a ring around the gonoplasm in the inner portion of the periplasm. They divide, and one or more of their daughter-nuclei enter into the gonoplasm and there fuse with the male nucleus or nuclei. It is remarkable that the sharp differentiation between the gonoplasm and the periplasm seems to be associated with the zonation stage of nuclear arrangement. Karyokinetic division of the nuclei occurs at this time simultaneously, and it seems as if this division has some connexion with the final cutting out of the oosphere. Perhaps the kinoplasm of the spindles acts in combination throughout the whole region of zonation and cuts out the compound oosphere in a manner somewhat similar to that by which the ascospores are cut out by the radiating kinoplasmic threads of the asters, which has been shown by Harper (11) to be typical of the formation of spores in asci. At any rate the processes are similar up to a certain point,- for in each instance the oosphere or the ascospores are formed from a dense protoplasmic mass which gradually collects at one point in the mother-cell and is distinguished from a differentiated, 222 Barker. — The Morphology and Developinent of less dense and more vacuolated protoplasm, and with which eventually become associated the nucleus or nuclei which produce the nuclei of the spores. The occurrence of nuclear divisions during the period of protoplasmic differentiation is also typical of both groups. The results of Wager (25 and 26), Trow (22), Berlese (1), and Miyake (28) on various other Oomycetes also agree in most details ; but the zonation stage of the nuclei is not so marked, nor is the protoplasmic aggregation so pronounced in the early stages. As Stevens remarks in connexion with Albugo Candida (21), it is the absence of this preliminary aggregation which precludes the early marshalling of the nuclei into the form of a hollow sphere. There are then many points in common between the methods of formation of oospheres in the Oomycetes and of ascospores in the Ascomycetes, and further investigation may reveal even closer resemblances in the behaviour of the kinoplasmic threads during the final mitosis during oogenesis in the former. The hypothesis that the oogonium has been evolved from a game- tangium, which has been considered by Stevens (21), makes those somewhat allied methods of spore-formation of great interest in conjunction with the hypothesis of the homology of the ascus with the zoosporangium. If it be assumed that antheridia and oogonia are homologous with gametangia, it is no great step further to admit the evolution of asci from zoosporangia, seeing that among the lower Algae gametangia and zoosporangia are in many cases identical. The view of Harper may therefore not be of such importance as at first appeared, especially when it is considered that the structures which show similarity in method of spore-formation also produce spores of a similar physiological character, the presence and survival of the periplasm being thus explained. The lack of forms intermediate in character between Oomy- cetes of the type of Peronospora omnivor a and Ascomycetes of the type of Monascus is a point of some importance because of the width of the gap separating these forms. The lower Ascomycetes, apart from the Gymnoascaceae, are distinguished by a complete loss of sexuality or by its isogamous character, the Ascocarp in Monascus . 223 and the Hemiasci with one exception, viz. Dipodascus, appear to be asexual organisms. The likely forms are thus limited to Dipodascus , the heterogamous Gymnoascaceae, and perhaps the Erysipheae. The features which ought to be specially noticed are the extent of the development of the sporophyte and the nature of the asci. The sporophyte in Dipodascus is very little developed. According to Juel (15) and Lager- heim (16) the £ sporangium 5 is formed by the fusion of two very similar hyphae. One of these, which is regarded as the female branch, then continues to grow considerably in length, and a large number of spores are eventually formed in this outgrowth. The nuclear behaviour, described by Juel, consists in the passage of a nucleus from the male branch into the female hypha, where it fuses with one of the nuclei of the latter, both branches being multinucleate. The fertilized nucleus then divides repeatedly, and eventually, around each of these daughter-nuclei, protoplasm collects and spores are formed as in a typical ascus, the only difference being in the total number of spores produced. The sterile nuclei of the female branch seem to persist until spore formation, but take no part in it. Juel regards the ‘sporangium’ as equivalent to the whole system of ascogenous hyphae and asci. The c sporangium ’ is accordingly to be looked upon as the sporo- phyte. Dipodascus therefore presents to those Oomycetes, in which the oospore itself on germination becomes a zoosporan- gium, exactly the same resemblances as Monascus does to the Oomycetes, which form promycelia. The resemblance is even closer, because in the other case the development of a simple form of ascocarp adds another complication. Dipodascus and Monascus seem thus to stand in much the same relation to one another as do Albugo Candida and Peronospora omnivor a, the distinction being rather greater, however, owing to the more highly evolved sporophyte in Monascus. The homology of the c sporangium ’ of Dipodascus to the zoosporangium of the Oomycetes thus appears at first to correspond with the homology of the ascus of Mon- ascus to the latter ; but this would make the ascus and the 224 Barker . — The Morphology and Development of ‘ sporangium ’ homologous, whereas it has been shown that the kind of homology between these structures is one between the whole group of asci, regarded as a unit, and the single ‘ sporangium.’ Ought not, accordingly, the zoosporangia of the Oomycetes to be classed in a similar manner into two groups, which might be called respectively the mega- and the micro-groups ? The mega-zoosporangium would, in this way, be looked upon as being formed from the whole or a portion of the thallus by the direct conversion of this into a sporangium ; while the micro-zoosporangium would be formed by a differentiation of the former into sporogenous and vegetative parts, the sporogenous portions constituting the zoosporangia and being formed as specialized branches of the latter. Two kinds of zoosporangia are found among the Oomycetes. viz. the large sporangia of the Saprolegniaceae and the small conidium-like sporangia of the Pythiaceae and the Peronosporaceae. They may be taken as furnishing respec- tively examples of mega- and micro-sporangia, and the homo- logies as being between the sporangium of the former and the combined conidiophore (or sporangiophore) and conidia (or sporangia) of the latter ; thus furnishing an example com- pletely parallel with that of the ‘ hemi-ascus ’ or e sporangium ’ and the ascus. The existence of such a form as Dipodascus must hence supply a strong argument in favour of the hypo- thesis of a relationship between the Oomycetes and the Asco- mycetes. The organism itself can hardly be regarded as an intermediate form between Monascus and the nearest Oomy- cete, on account of the distinctions drawn above between asci, hemi-asci, mega- and micro-sporangia : it is, rather, a parallel form, but closer to its Albugo type than Monascus is to the Phytophthora type for reasons given above. It is, in addition, of importance as forming a link between the other Hemiasci, which are all asexual forms, and the sexual Asco- mycetes. The relationship of these two groups follows from the above. The Gymnoascaceae, although simple in structure, do not appear to stand in a position intermediate between Monascus the Ascocarp in Monascus, 225 and the Oomycetes. A comparison with the former has already been made, in which the most striking difference is the behaviour of the ascogonium, which becomes divided up into several cells, ascogenous branches being formed from each. This behaviour corresponds to that of the ascogonium of the Erysipheae, the members of which group show various degrees of complexity of the process. The simplest, or most reduced, method occurs in Sphaerotheca , in which form Harper (31) has shown that fusion takes place between the antheridium and ascogonium, followed by the fusion of a male and female nucleus and the division of the ascogonium into a few cells, one of which becomes converted directly into the single ascus. The nature of this ascus is therefore not quite the same as that of the ascus of Monascus , nor yet of the ‘ sporangium ’ of Dipodascus , but stands between the two. There is a differentiation of the ascogonium into two portions, one sterile and the other sporogenous, the two parts being separated by walls. In Dipodascus the two portions are either undifferentiated or else the sterile portion is absent. In Monascus the ascogonium itself may be considered sterile, but a portion of its branches sporogenous. There does not seem to be a form corresponding to Sphaerotheca among the Oomycetes. Perhaps the Erysipheae, the Gymnoascaceae and other Plectascineae are derived from a Dipodascus- like fungus, and are through that related to those Oomycetes, the sporo- phyte generation in which is represented simply by a zoo- sporangium. Their relation to Monascus would then be close but indirect. The Erysipheae, however, may be regarded as derived from the Monascus type, if the view that Sphaerotheca is a reduced form be accepted. The genus Erysiphe is most like the Monascus type. The ascogonium, after fertilization by a single nuclear fusion, divides into a row of several cells from the penultimate one of which the whole of the ascogenous hyphae probably arise, according to Harper (9). The asco- genous hyphae are but feebly developed and soon become in part converted into asci. The penultimate cell of the ascogonium corresponds thus to the central cell of Monascus , Q 226 Barker.— The Morphology and Development of and if Went’s statement as to the division of the ascogonium into three cells in Monascus purpureus is correct, the resem- blance of the ascogonium in this species to that of Erysiphe is still greater than that of the c Samsu ’ species. The Sphaero- theca form would thus be attained by the gradual loss of the ascogenous hyphae. Of the other lower Ascomycetes, Eremascus , which retains a sexual process but is isogamous, is nearer to the Dipodascus type, and so probably are also the Saccharomycetes through the sexual form, Zygosaccharomyces (32). It is difficult indeed to separate either group from the Hemiasci. Endomyces shows occasionally a small hypha attached to the developing ascus. According to Brefeld (2) no sexual process takes place between the two structures, but the small hypha may be regarded as a rudimentary male branch. Thus this genus also approaches very nearly the Dipodascus type, and can only be sepa- rated from the Hemiasci by the limited number of spores in the ascus, as is the case with the other two groups just mentioned. The limited number of spores is doubtless necessitated by the small size of the ascus, the Saccharo- mycetes showing a variation in number corresponding with the size of the cell. The close relationship therefore indi- cated between these groups renders very interesting the positions of the three forms, Ascoidea rubescens , Endomyces decipiens , and Saccharomyces anomalies , all of which produce characteristic hat-shaped spores, such as are formed by no other Fungi (33). The Exoascaceae and Ascocorticaceae seem to belong to the Dipodascus type rather than the Monascus type through such forms as Taphrina . While Dipodascus appears to be the only sexual genus among the Hemiasci at present known, several of the asexual genera of that group merit further consideration. Of these Protomyces has been placed at different times by De Bary among the Ascomycetes (7) and later among the Ustilagineae (8) ; by Schroter in a special group, the Protomycetes (18), and later among the Hemiasci (19) ; and by Brefeld among the the Ascocarp in Monascus . 227 Hemiasci (2). It is now generally accepted as belonging to the latter group. It is characterized by a septate mycelium, intercalary cells of which swell up and clothe themselves with a thick wall, forming chlamydospores. They germinate by the bursting of the outer wall and the escape of the proto- plasmic contents, surrounded by a wall. The contents of the cell thus extruded are multinucleate, and arrange themselves in a wall layer dividing up into spores, which eventually collect at the tip of the elongated cell thus converted into a sporan- gium by their division. Popta (17) has recently shown that no periplasm is produced during the division into spores, and accordingly regards the genus as being nearer to the Phyco- mycetes than Ascoidea, in which he finds periplasm produced, and therefore regards it as approaching the Ascomycetes. The chlamydospores of Protomyces resemble in appearance the intercalary ripened oogonia of Pythium and many Perono- sporaceae. As De Bary (5) has shown, the latter are often fertilized by an antheridium formed from the cell immediately beneath or above, the fertilization taking place through the wall separating the two cells. The figures of the early stages of chlamydospore formation in Protomyces given by De Bary (7) and Brefeld (2) show that the cells on either side of the young chlamydospore are filled with dense protoplasm, so that these structures may be looked upon as representing the intercalary oogonia and antheridia of the above-mentioned Oomycetes. There is certainly no evidence of any fusion between these structures through the separating wall, but it may easily have been overlooked, as has happened in the cases of many Asco- mycetes, where the fusion is only of sufficient size to allow the passage of a nucleus. The nuclear behaviour during the chlamydospore formation is entirely unknown at present, so that it is impossible to do more here than point out the resemblance to the intercalary sexual organs of the Oomycetes. But if it prove to be the case that the chlamydospore is sexually produced, it must then be regarded as an oospore, and we should have a member of the Hemiasci which retains its oospore stage. It would then have to be regarded as an Q 2 228 Barker . — The Morphology and Development of important connecting link between the Oomycetes and Asco- mycetes. Holtermann (13) has described a form, Conidiascus , which he places among the Hemiasci, in which reproductive bodies are produced as conidia like those of Peronospora , which later produce a few spores by the division of their contents, epiplasm being formed during the division. This form of reproduction is regarded as intermediate between conidia and asci, and thus serves to connect zoosporangia, which are homologous in the Peronosporaceae with conidia, and asci. The processes leading up to the formation of these structures do not seem to be thoroughly known at present, so that the comparison cannot be extended here. Popta (17) has shown that the method of spore-formation in Ascoidea is more nearly allied to the Ascomycetous type than to that of the Phycomycetes, owing to the occurrence of periplasm. The sporangia are apparently produced asexually. Harper (11) believes that Popta's results either indicate a method of division similar to that which he has described for Pilobolus , or that the process is unique and differs from that occurring in the sporangia or asci studied up to that time. Having reviewed briefly some of the features which seem to be of most importance in the question of relationship, there remain a few points which may be further considered. It has been seen that the antheridia and oogonia of the Oomycetes have probably been evolved from gametangia, the separate motile gametes of which have lost their individuality, and in the simplest forms such as Albugo Bliti , while several remain functional, others have lost their sexuality, or rather remain unfertilized, and constitute the periplasm, which may be supposed to have thus originated. Other forms, such as Peronospora parasitica , show a higher degree of differentiation, only one male and one female gamete remaining functional. Similarly, among the Ascomycetes, which still possess an archi- carp of functional male and female organs, Monascus and Pyronema behave like Albugo Bliti , and Sphaerotheca — and Dipodascus among the Hemiasci — like Peronospora parasitica. 229 the A scocarp in Monascus . In the cases of Monascus , Pyronema , and Dipodascus super- numerary gametes occur in the female organ, corresponding to the periplasm of the Peronosporaceae. In Sphaerotheca only one gamete seems to be produced in each organ ; but in this case the supernumerary gametes may be considered to have disappeared during the course of evolution, since peri- plasm is not needed to produce a wall for an oospore, which function it assumes in the Peronosporaceae, affording perhaps a reason for its presence in that group when only one gamete of the female organ is functional. In Pyronema and probably also Monascus , the development and behaviour of the gametes is like those in Albugo Bliti. The gametes in both organs are produced by nuclear division occurring shortly before fertilization. The female gametes aggregate into a ring or dense mass, from which the functional gametes separate. The behaviour after fertilization is the first important point of difference. Leaving out of the question the definite oospore stage of the Oomycetes, we find that the fertilized gamete or gametes in Albugo produce directly by division numerous spores. Dipodascus and Eremascus behave similarly. In Phytophthora omnivor a and most Ascomycetes, hyphae are produced from the fertilized cell which bear zoosporangia or asci. In many Oomycetes a mycelium is produced which bears fresh sexual organs. Thus in the Ascomycetes there is inter- calated a definite phase in the life-history, which may be regarded as a sporophyte generation between the gameto- phyte generations. In the Oomycetes certain members show signs of such a phase, but it is by no means general. Seeing that Albugo Bliti still possesses the most primitive form of fertilization, and, in addition, presents an example of an inter- calated sporophyte generation, the possession of two genera- tions by the ancestral Oomycetes ought perhaps to be assumed; and those members of that group which do not possess both ought accordingly to be regarded as having lost the sporophyte phase. The question oPrelationship thus turns on the homo- logy of the ascus with the zoosporangium. At present very 230 Barker . — The Morphology and Development of little is known of the cytological behaviour in the latter leading up to spore-formation. Wager (25) has shown that five to eight nuclei are present in the zoosporangia of Albugo Candida , when those bodies are cut off by a wall from the sporangiophore. Each nucleus remains undivided and becomes the nucleus of a zoospore, which bodies are formed according to Biisgen (4) by the simultaneous division of the protoplasm into several distinct portions. This process is thus far removed from that occurring in typical asci. But the ascus must be regarded either as a specialized sporangium or as an entirely new structure without any homologues : and it has been seen that a method of spore-formation, which may be looked upon as approaching that found in asci, occurs in the oogonium of Albugo , and that the latter organ is probably a derivative of a gametangium. The balance of probability thus seems to rest with the view that the ascus and the zoosporangium are homologous. Moreover, Harper’s results have been obtained from typical highly evolved asci and sporangia, and it is hardly to be expected that such diverse and characteristic structures would exhibit signs of a common origin, as might be obtained from more primitive forms. Ikeno’s studies on Taphrina (14) show that the method of spore-formation in the asci of that genus is very different from Harper’s typical method. Apart, however, from the difficulty of the manner of cell- division there is another obstacle against the acceptance of these homologies. It arises from the behaviour of the nuclei in connexion with the formation of a typical ascus. The typical ascus is formed by the cutting off of a penultimate cell from an ascogenous hypha containing two nuclei which fuse together, leaving the young ascus uninucleate. The ascus speedily becomes multinucleate by repeated divisions of the fusion-nucleus, and each of the last formed daughter-nuclei becomes the nucleus of an ascospore. In the Oomycetes the antheridia, oogonia and zoosporangia are multinucleate from the moment of formation, and the nuclei in the latter structures become without any division the nuclei of the zoospores. the Ascocarp in Monasciis. 231 As far as the difference between the young multinucleate sporangium and the young binucleate ascus is concerned the difficulty is perhaps not serious. In discussing earlier the nature of the ascus in various genera, it was seen that in some cases it was simply the fertilized ascogonium ; in others that it was limited to a portion of that organ, the remainder being cut off into separate cells ; and in others that it was a branch of the system of hyphae which was produced from the ascogonium. In other words, the result of the sexual process in the Ascomycetes varies, a greater or less distinction into fertile and sterile units being met with. The same kind of distinction is found in the Peronosporaceae in the germination of the oospore. The difference then comes simply in the ex- treme case to this : in the zoosporangium of the promycelium of Phytophthora omnivor a (assuming that the nuclear behaviour is similar to that of Albugo) the nuclei of the spores are different- iated before enclosure of the mother-nuclei in the sporangium ; and in the ascus of Pyronema , for example, the spore-nuclei are not formed until after enclosure within the ascus. That this difference is not seriously opposed to the idea of relation- ship is clear from the fact that the gameto-nuclei of the Oomycetes are not differentiated until after enclosure in the gametangia. The fusion of the two nuclei of the young ascus has apparently no parallel among the Oomycetes. It may be mentioned that Trow (22) found curious ‘ double ’ nuclei in germinating oospores and conidia oiPythium ultimum , which may represent pairs of nuclei in the act of fusing, but whose significance is entirely obscure. The only other fusions which have been observed in that group are the sexual fusions in the oogonia. However, since the meaning of the fusions in asci does not seem to have been satisfactorily determined, the exact bearing of the phenomena on the question of relationship cannot be estimated at present. In the foregoing discussion stress has been laid upon the analogy of spore-formation in oogonia and asci. The periplasm of both organs ought, therefore, to be regarded as having 232 Barker . — The Morphology and Development of originated by similar means. It has been already mentioned that the periplasm of oogonia probably represents the sexually functionless elements of a gametangium that was originally completely fertile. Assuming the origin of the ascus from the zoosporangium, the sterile nuclei have either disappeared or are represented by the two nuclei which are formed at the same time as those which fuse in the young ascus, one of which is cut off into the terminal cell of the ascogenous hypha and the other into a cell immediately beneath the penultimate ascus. The latter appears to be the most likely alternative, in which case the periplasm of the ascus represents a portion of the non-sporogenous protoplasm which has escaped being cut off into the sterile cells with the sterile nuclei. The other reproductive organs of the Oomycetes and the Ascomycetes are in many cases clearly homologous. The conidia of the latter undoubtedly correspond to those of the Peronosporaceae, in which order many examples are presented of the transition from the zoosporangial to the conidial con- dition. In the above comparisons only those Ascomycetes which possess a functional archicarp have been considered. It is, however, generally admitted by most botanists, with the exception of Dangeard, that the other members of that group are to be looked upon as sexually degenerate, and are there- fore considered as having originated from sexual ancestors. Summarizing, Albugo , Pyronemct , and Monascus possess a very characteristic and probably primitive method of multiple fertilization. The germination of the fertilized egg in both groups shows gradations between a direct division into spores, e. g. Albugo and Dipodascus , and a comparatively highly evolved differentiation into sterile and sporogenous structures, e. g. Phytophthora omnivor a and Pyronema. Combining these characters, the ancestral form of the Oomycetes was probably an organism possessing the method of multiple fertilization, the compound egg of which gave rise to numerous spores only by division, i. e. the species Albugo Bliti and A. Portulacae represent in those characters the the A scocarp in Monascus. 233 primitive form. For similar reasons the ancestor of the Ascomycetes possessed probably the same characters, but no known member of the group now possesses these characters in an unaltered form, Monascus being the simplest as far as fertilization is concerned, and Dipodascus and Eremascus as far as the behaviour of the egg. The dividing line between the two groups seems to have originated by the development of the oospore stage on the one hand and the development of the ascospore stage on the other. The probable origin of the coenogamete from gametangia, and the retention of zoosporangia in many Oomycetes, afford a link with the lower Algae. The resemblances which have been pointed out between the Florideae and certain Ascomycetes by various authors may be explained by supposing the origin of the former from the same Algal ancestor, a somewhat parallel method of evolution having occurred from that form. Certainly for most Ascomycetes there seems to be no reason for looking back for their origin to a simpler form than that represented by Albugo Bliti in those characters which have just been pointed out. In conclusion, I wish to acknowledge my indebtedness to Professor Marshall Ward for much valuable help and advice, and also for permission to carry on the work in the Cambridge University Botanical Laboratory ; to Miss Dale for information on the genus Gymnoascus, as yet unpublished; and to Messrs. D. T. Gwynne-Vaughan and R. H. Yapp for the material and for information concerning its economical use. 234 Barker. — The Morphology and Development of BIBLIOGRAPHY. 1. Berlese. Ueber die Befruchtung und Entwickelung der Oosphare bei den Peronosporeen. Prings. Jahrb. der Bot., Bd. xxxi. 2. Brefeld. Untersuchungen aus dem Gesammtgebiete der Mykologie. IX. Heft : Die Hemiasci und die Ascomyceten. 3* Botanische Untersuchungen iiber Sehimmelpilze. II. Heft : Die Entwickelungsgeschichte von Penicillium. 4. Busgen. Die Entwickelung der Phycomycetensporangien. Prings. Jahrb. der Bot., Bd. xiii. 5. De Bary. Beitrage zur Morphologie und Physiolog-ie der Pilze. Beitr. iv. 6. Zur Kenntniss der Peronosporeen. Bot. Zeit., 1881. 7. Beitrage zur Morphologie und Physiologie der Pilze. Beitr. i. 8. Vergleichende Morphologie und Biologie der Pilze. Leipzig, 1884. 9. Harper. Kerntheilung und freie Zellbildung im Ascus. Prings. Jahrb. der Bot., Bd. xxx. 10. Sexual Reproduction in Pyronema Confluent and the Morphology of the Ascocarp. Ann. Bot., vol. xiv. 11. Cell-division in Sporangia and Asci. Ann. Bot., xiii. 12. Harz. Physomyces heterosporus, n. sp. Bot. Cent., Bd. xli. 13. Holtermann. Mycologische Untersuchungen aus den Tropen. Berlin, 1900. 14. Ikeno. Studien iiber die Sporenbildung bei Taphrina Johansoni , Sad. Flora, 1901. 15. Juel. Ueber Zellinhalt, Befruchtung und Sporenbildung bei Dipodascus. Flora, 1902. 16. Lagerheim, von. Dipodascus albidus , eine neue geschlechtliche Hemiascee. Prings. Jahrb. der Bot., Bd. xxiv. 17. Popta. Beitrag zur Kenntniss der Hemiasci. Flora, 1899. 18. Schroter. Protomyces graminicola. Hedwigia, 1877. 19. Die Hemiasci in Engler und Prantl’s ‘ Die natiirlichen Pflanzen- familien/ 1. 1. 20. Stevens. The Compound Oosphere of Albugo Bliti. Bot. Gaz., 28. 21. Gametogenesis and Fertilization in Albugo. Bot. Gaz., 32. 22. Trow. Observations on the Biology and Cytology of Pythium ultimum , n. sp. Ann.JBot., 1901. 23. Uyeda. Ueber den ‘ Benikoji ’ Pilz aus Formosa. Bot. Mag., 1901. 24. Van Tieghem. Monascus , genre nouveau de Pordre des Ascomycetes. Bull. de la Soc. Bot. de France, 31. 25. Wager. On the Structure and Reproduction of Cystopus Candida. Ann. Bot., x. 26. On the Fertilization of Peronospora parasitica. Ann. Bot., xiv. 27. Went. Le champignon de l’Ang-Quac. Ann. des Sci. Nat., Bot., serie viii. 1. the As cocarp in Monascus. 235 28. Miyake. The Fertilization of Pythium de Baryanum. Ann. Bot., xv. 29. Woronin. Beitrage zur Morphologic und Physiologic der Pilze. Beitr. ii. 30. Beitrage zur Morphologic und Physiologic der Pilze. Beitr. iii. 31. Harper. Die Entwickelung des Peritheciums bei Sphaerotheca Castagnei. Ber. der Deut. Bot. Gesell. , Bd. xiii. 32. Barker. A conjugating Yeast. Phil. Trans. Roy. Soc., Ser. B. 203. 33. — A fragrant Mycoderma Yeast, Saccharomyces anomalus. Ann . Bot. 1900. EXPLANATION OF FIGURES IN PLATES XII and XIII. Illustrating Mr. Barker’s paper on Monascus. Fig. 1, a-e. Successive stages in the germination of a conidium. x 400. Fig. 2, a-h. Successive stages in the formation of an archicarp. x 800. Fig. 3, a, b. Two periods in the development of an archicarp, showing the branching of the antheridial branch and the formation of a conidium by it. x 650. Fig. 4. Intercalary formation of an archicarp. x 650. Fig. 5. An ascogonium spirally curved around an antheridium. x 800. Fig. <5. A conidium functioning as an antheridial branch, x 650. Fig. 7. Archicarp formation at the base of a chain of conidia, the lowest 01 which behaves as an antheridial cell, x 650. Fig. 8. Showing point of fusion between the ascogonium and the antheridial branch at some distance behind the apex of the former, x 800. Fig. 9. Showing fusion between the ascogonium and the antheridial branch, in which the papilla developed from the latter is conspicuous, x 3000. Fig. 10. Formation of papilla on the antheridial branch beyond the apex of the ascogonium, the latter having ceased to grow, x 650. Fig. 11, a-d. Development of investing hyphae. Successive stages, x 1000. Fig. 12. Formation of auxiliary investing hyphae. x 1500. Fig* I 3> ct~c. Successive stages in the development of an ascocarp, showing the origin and development of the 4 internal ’ hyphae and asci. x 1000. Fig. 14. A branch bearing an ascocarp and clasping hyphae. x 800. Fig. 15, a-c. Nuclear structures in archicarps. (a) Fusion between the asco- gonium and antheridium doubtful : both organs crowded with nuclei, especially at the place where fusion occurs, (b) A nucleus occupying the canal between the ascogonium and antheridium. Central cell cut off and filled with nuclei. Nuclei in male branch comparatively few with sharp outlines, (c) Aggregation of nuclei in the centre of the swelling central cell, x 1 200. Fig. 16. Section through young ascocarp showing comparatively large central cell surrounded completely by investing hyphae. x 1000. 236 Barker . — Ascocarp in Monascus. Fig. 17. Section through an ascocarp of the same age with the central cell not completely in view, x 1000. Fig. 18. Section through a slightly older ascocarp, a small part only of the central cell being included, x 1000. Fig. 19. Section through an ascocarp of the same age, showing a large undivided central cell, x 1000. Fig. 20. Similar section through a rather older ascocarp, showing a beak -like protuberance of the central cell, x 1000. Fig. 21. Section through an ascocarp showing a large central cell with a small nest of ascogenous hyphae at one point of its surface, x 1000. Figs. 22-24. Similar sections, showing varying position of the nest of ascogenous hyphae. x 1000. Fig. 25. Section through an ascocarp, showing the central cell as a complete ring around the ascogenous hyphae. X 1000. Figs. 26-31. Various stages in the further development of the ascocarp, showing the increasing complexity of the internal ascogenous hyphae and variations in the extent of the development of the central cell, x 1000. Fig. 32. Section through an ascocarp containing ripe asci. No trace of the central cell, which has degenerated, x 1000. Fig. 33. Section through a ripe ascocarp, showing spores lying free within the sporangium-like fructification, x 500. Fig. 34. Surface view of a young ascocarp, showing a conspicuous hyphal-like protuberance of the central cell. The investing hyphae are omitted with the exception of the cross sections around the central cell, x 1000. Figs. 1-14 were drawn from living material observed in hanging-drop cultures of beer-wort agar; Figs. 15-34 from fixed and stained material. Fig. 15, a , b, c, stained by the haematoxylin-iron-alum method, and Figs. 16-34 with safranin. r JlrinoLs of Botany BARKER MONASCUS VoimiPiM. \ i' University Press, Oxford. JJrmcds of Botany Voixmpixu. University Press, Oxford BARKER. MON ASCUS. .■Sr - 3 <_Jlnnals of Botcony VoUvji, pim. University Press, Oxford. BARKER. MONASCUS Proteolytic Enzymes in Plants 1 . BY S. H. VINES, M.A., D.Sc., F.R.S., P.L.S., Sherardian Professor of Botany in the University of Oxford. INCE the publication of my paper on tryptophane ( 1 ) in O the March number of the Annals for 1902, I have accumulated a number of new facts relating to the distribu- tion of proteolytic enzymes, and of tryptophane, in plants, which I now place on record. There is at present evidence that enzymes which digest proteids (proteases) occur in a number of isolated cases ; in certain lowly Algae, in some Fungi, in various Phanerogams. The evidence is not, however, of the 'same kind in all cases : in some it is direct, in others only indirect. The indirect evidence amounts merely to this, that the plants in question can be nourished by peptone or other proteid, no demonstration of the digestive process having been given. This applies to the Algae, Scenedesmus acutus , Chlorella vidgaris , Chlorospora limicola , investigated by Bey- erinck ( 2 ) ; to certain Moulds [Aspergillus niger , Penicillium glaucum ) ; and to the insectivorous Drosera , Dionaea , and Pinguicula. The direct evidence consists of the demonstration of the digestive process by means of chemical tests. This is forth- coming in the case of certain Bacteria, of Yeast ( Saccharomyces Cerevisiae ) ; and, among Phanerogams, of the insectivorous Nepenthes , of many seeds, of some fruits such as the Pine- 1 A preliminary account of these observations was given at a meeting of the Linnean Society of London, on Nov. 20, 1902. [Annals of Botany, Vol. XVII. No. LXV. January, 1903.] 238 Vines. — Proteolytic Enzymes in Plants. Apple (. Ananas sativus ), and of certain laticiferous plants such as the Papaw ( Carica Papaya) and the Fig ( Ficus Carica). In all these cases the process includes both the peptonization of the more complex proteids and the proteolysis of the simpler proteids. I would recall the suggestion made years ago by Claude Bernard and by Sachs, that a digestive enzyme may be presumed to be formed in all organs, such as seeds, fruits, bulbs, tubers, &c., in which proteids are stored. This sugges- tion has already been fully verified in the case of seeds : indeed the ascertained facts warrant the inference that a digestive enzyme is produced in all germinating seeds. The object that I had in view, on commencing these investigations, was to supply similar verification in the other cases, and so to add to the number of known instances of the occurrence of these enzymes in plants. I have, however, carried them far beyond these prescribed limits and in an unexpected direction, as the following pages will show. It has been customary, in investigations of this sort, to employ relatively intractable proteids (using the word in a quite general sense), either blood-fibrin or coagulated egg- albumin, as the digestible material ; and the tests subse- quently applied have been the biuret-test and others which indicate the presence of the lower proteids, viz. albumoses and peptones. That is to say, the investigation has been directed to the question as to whether or not a peptonizing enzyme was present. The methods that I have adopted are quite different to these. In the first place, it has to be borne in mind that the enzymes in the tissues of plants are not called upon to digest fibrin and egg-albumin. It is true that in several cases (e.g. Pine-Apple, Papaw, Fig, Yeast) enzymes have been found which are capable of digesting these sub- stances : but it does not follow, as seems to have been generally assumed, that because a vegetable juice or extract cannot digest them, it therefore contains no enzyme at all. As I long ago pointed out (3), the proteids of plants are chiefly globulins and albumoses : it is therefore obvious that Vines, — Proteolytic Enzymes in Plants, 239 these are the proteids to be employed in the search for enzymes in plants. Consequently I have employed as di- gestible material in these experiments either the proteids naturally present in the juice or in the tissue of the plant ; or, when proteid material had to be supplied, the substance sold as { Witte-peptone,’ a dry powder consisting of a mixture of albumoses and some peptone. Moreover, the immediate object of my search was not a peptonizing , but a proteolytic enzyme ; not an enzyme, that is, which hydrolyzes the higher proteids into the lower, but one that decomposes the proteid molecule altogether. The test of digestive activity has ac- cordingly been the tryptophane-reaction : that is, the treat- ment of the acid digested liquid with chlorine-water which produces a characteristic, more or less marked, pink or violet colouration if tryptophane be present ; and if tryptophane be present, it is presumptive evidence that proteolysis has taken place. Incidentally, however, I found it necessary to make some experiments with the more complex proteids. Whilst they were nearly always successful when Witte-peptone was the material supplied, the results with fibrin, raw egg-albumin, and commercial casein, were often negative : but experiments with milk showed that the enzymes detected could act upon caseinogen, in several instances. The plant-material used was, in many cases, the juice, when the parts to be investigated were sufficiently succulent, such as fruits, &c. When the parts did not yield enough juice, I had recourse, in the first instance, to watery extracts. But I sometimes found juices, and especially watery extracts, to be unsatisfactory : when unfiltered they were too thick or too highly coloured, when filtered they were almost or altogether inert. After many trials I found that the best method of preparing such material as leaves, stems, roots, &c., was to slightly bruise pieces of them in a mortar ; when so prepared, they were placed in the experimental bottles with distilled water, or other liquid, and the digestible substance (Witte-peptone, fibrin, &c.) then added. 240 Vines. — Proteolytic Enzymes in Plants. The chief source of error to be avoided was the putrefaction of the digesting mixtures. When the period of digestion was brief, extending over three or four hours or even more, this source of error did not arise : in prolonged digestions it was eliminated by the use of antiseptics, such as hydrocyanic acid (HCN), hydrochloric acid (HC1), or chloroform-water. The mixtures without antiseptics generally showed no sign of putrefaction in the course of the experiment, but occasionally they developed an offensive odour : it is, however, not neces- sary to attach importance to those results, as the evidence afforded by the antiseptic experiments is conclusive in itself. In many instances the results were controlled by parallel experiments in which the vegetable matter under investigation had previously been boiled. The tryptophan e-test was usually applied directly to the digested liquid acidified, when necessary, with acetic acid : in only a few cases (e.g. leaf and root of Dandelion) did the liquid become too highly coloured, in the course of digestion, to admit of accurate observation of the tryptophane-reaction. In a good many cases (e.g. Apple, leaf of Scolopendrium , tuber of Helianthus tuberosus') a marked yellow colour was produced on the addition of the chlorine-water ; but this did not prevent the detection of the tryptophane-reaction. The various intensities of the tryptophane-reaction are described by the series of terms — faint, distinct, marked, strong. The fact that when the vegetable substance had previously been boiled the digested liquid gave no tryptophane-reaction, or only a faint one, due to the presence of tryptophane in the substance itself, proves that the Witte-peptone and other proteids used contained no tryptophane to begin with. It should be mentioned that the temperature of the incu- bator or thermostat, in which the liquids were set to digest, was about 40 ° C. in all cases. In some cases acid (either HC1 or citric acid) was added to the liquids to be digested : but this is not necessary, since all the liquids used were either acid to begin with, or they naturally became so in the course of digestion. When acid Vines. — Proteolytic Enzymes in Plants . 241 was added it was generally found to promote proteolysis. In other cases, the liquid was made alkaline with Na 2 C0 3 , with the effect of sometimes promoting, sometimes retarding diges- tion, but never inhibiting it. Experiments with Witte-Peptone. Most of these experiments were made with various parts of Phanerogams, such as fruits, bulbs, tubers, stems, leaves, roots : only a few were made with seeds, as these have been already so fully investigated. I have included in the experi- ments the leaves of a Fern ( Scolopendrium vulgar e ) ; and a single Fungus, the Mushroom ( Agaricus campestris). I give this last experiment first* It must be borne in mind that in all cases more or less proteid matter, belonging to the juices or tissues under experiment, was present in addition to the Witte-peptone added. Agaricus campestris. 5 grms. of bruised Mushroom (gills excluded) were placed in each of the bottles Nos. 1, 2, 3, of about 40 cc. capacity: in the case of No. 2, the portion of Mushroom was first of all boiled : to each bottle was added 0-3 grm. of Witte-peptone, and to No. 3, 1*5 cc. of 4 % HCN, the bottles having all been filled up with distilled water. After 5 hours’ digestion in the incubator, No. 1 gave a strong tryptophane-reaction, No. 2 a distinct reaction, and No. 3 a marked reaction : clearly proteolysis had taken place in Nos. 1 and 3 : the reaction in No. 2 is to be attributed to the presence of tryptophane in the tissue to begin with. There can be little doubt that further investigation will show that the capacity for active proteolysis is generally possessed by the Fungi. Seeds. The observations that I have made on Green Peas ( Pisum sativum ) are of some interest. The watery extract of Green Peas gives no tryptophane-reaction, but acts strongly on Witte-peptone. R 242 Vines. — Proteolytic Enzymes in Plants. The extract is turbid, greenish, neutral : 30 cc. were placed in each of four bottles ; 6 drops of 4 % HCN solution were added to each. Further additions were made as follows: 1. Extract and HCN only; nothing added. 2. ., „ with 2 drops of strong HC 1 . 3. „ „ with 2 drops of strong HC 1 and -3 grm. of Witte-peptone. 4. the same mixture as 3, but boiled (control). After 3^ hours in the incubator, Nos. 1 and 2 gave distinct, and No. 3 marked, tryptophane-reaction: No. 1 had become slightly acid: no tryptophane-reaction in No. 4. After 22 hours in the incubator, No. 4 still gave no tryptophane-reaction, whilst all the others gave a strong reaction : No. 1 was strongly acid. It is clear, therefore, that Green Peas contain a proteolytic enzyme acting in the presence of HC 1 . I have also made some observations on the ‘germ’ of Wheat ( Triticum vulgar e)\ that is, the embryos removed from the grain in the process of milling : the presence of a proteolytic enzyme is clearly demonstrated. 50 grms. of ‘ germ/ ground to a fine powder, were extracted with 250 cc. of distilled water: the liquid, after straining through muslin, is turbid, slightly acid, and gives no tryptophane-reaction : 50 cc. of the liquid were placed in each of three bottles, and treated as follows : 1. added 0-5 grm. Witte-peptone and 10 drops of 4 % HCN. 2. „ 10 drops of 4 % HCN. 3. „ 0-5 grm. Witte-peptone, then boiled, and added 10 drops of 4 % HCN (control). After 4-| hours in the incubator, No. 1 gave a strong tryptophane- reaction, No. 2 a faint reaction, No. 3 no reaction. Fruits. In view of Green’s discovery ( 4 ) of a protease in the Kachree Gourd ( Cncumis utilissiimis , a variety of C. Melo ), I have given special attention to the Cucurbitaceae, and have found such a body in all the species examined, viz. a yellow, smooth-skinned, variety of Melon ( Cticumis Melo ) largely Vines . — Proteolytic Enzymes in Plants. 243 imported from Spain; the Cucumber (Cucumis sativus') ; the Vegetable Marrow ( Cucurbita Pepo var. ovifera) ; the Squirt- ing Cucumber ( Ecb allium Elateriuvi). The seeds and the rind were previously removed in most cases. Cucumis Melo. The expressed juice is a turbid, acid liquid, giving distinct trypto- phane-reaction : 30 cc. of it were placed in each of three bottles, and treated as follows: — 1, nothing added: 2, added 0-3 grm. Witte- peptone : 3, added 0*3 grm. of Witte-peptone, and acidified with HC 1 to 0-18 %. After 4 hours in the incubator, the tryptophane-reaction had become rather stronger in Nos. 1 and 3, and was marked in 2 : 19 hours later, it was rather stronger in 1, about the same in 2, and strong in 3. Cucumis sativus . The material used in the first experiment consisted of field or ridge Cucumbers which had begun to turn yellow, and were therefore nearly ripe. The expressed juice was turbid, greenish, acid, giving distinct tryptophane-reaction : 30 cc. of it were placed in each of three bottles, treated as follows: — 1, nothing added: 2, added 0*3 grm. Witte- peptone : 3, added 0-3 grm. Witte-peptone, and acidified with HC 1 to 0-18 %. After 3 hours in the incubator, the tryptophane-reaction in No. 1 was as at first, whilst it had become marked in 2 and 3 : 2-| hours later it was more distinct in 1, and strong in 2 and 3. A second experiment was made with green Cucumbers grown in a house ; the juice of this unripe fruit gave no tryptophane-reaction to begin with. 50 cc. of the juice were placed in each of two bottles ; to No. 1 nothing was added; to No. 2, 0-25 grm. Witte-peptone. After 2 hours in the incubator, No. 1 gave a distinct, and No. 2 a marked, tryptophane-reaction : after 24 hours’ digestion the reaction of No. 1 was about the same, whilst that of No. 2 had become strong. Cucurbita Pepo var. ovifera. The expressed juice of the Vegetable Marrow is a turbid, yellowish, almost neutral liquid, giving a marked tryptophane-reaction. 244 Vines —Proteolytic Enzymes in Plants . The following experiment was made with small pieces of the fruit that had been bruised in a mortar: io grms. of the bruised fruit were placed in each of four bottles, of about 40 cc. capacity, with 0-3 grm. of Witte-peptone : No. 1 was filled up with distilled water. No. 2 „ ,, chloroform-water (0-5 %). No. 3, the material was boiled with the water before adding the Witte-peptone. No. 4 was filled up with distilled water, and 1 cc. of 4 % HCN added. After 5 hours in the incubator, the results were : No. 1 gave a marked tryptophane-reaction. No. 2 ,, distinct „ „ No. 3 „ faint No. 4 „ distinct „ „ 18 hours later, the reaction was marked in Nos. 2 and 4, and still faint in No. 3. Ecb allium Elalerium. The expressed juice of the fruits of the Squirting Cucumber is mucilaginous and acid, giving a faint tryptophane-reaction. 20 cc. of the juice were placed in each of two bottles, to one of which nothing was added, to the second 0-2 grm. of Witte-peptone. After 6 hours in the incubator, the contents of the first bottle gave a faint, those of the second a marked, tryptophane-reaction. The following experiments were made with fruits belonging to various orders other than the Cucurbitaceae. Musa sapientum. The watery extract of the ripe Banana is a mucilaginous, acid liquid, giving distinct tryptophane-reaction ; on account of its viscidity, it could not be satisfactorily used : small pieces of the fruit were used instead. 10 grms. were placed in each of two bottles with 40 cc. of distilled water: to No. 1 nothing further was added: to No. 2, HCN to o-i %. After 5^ hours’ digestion, No. 1 gave a marked, and No. 2 a distinct, tryptophane-reaction : 1 8 hours later, the reaction was stronger in both. Auto-digestion had taken place. Vines. — Proteolytic Enzymes in Plants. 245 In another experiment, the action of the fruit-tissue on Witte- peptone was observed. 5 grms. were placed in a bottle to which 20 cc. of distilled water, and the same quantity of chloroform-water, with 0*3 grm. Witte-peptone, were added. After 19 hours’ diges- tion the liquid gave a distinct tryptophane-reaction. The liquid of a control-experiment, containing no Witte-peptone, gave no reaction. Lycopersicum esculentum. The expressed juice of the Tomato is turbid, reddish in colour, acid, and seems to give a tryptophane-reaction, but this is difficult to decide on account of the colour of the liquid. 30 cc. of the juice were placed in each of three bottles : to No. 1 nothing was added; to No. 2, 0-3 grm. of Witte-peptone and 0-3 cc. of 4 % HCN ; to No. 3, 0-3 grm. of Witte-peptone and 1-5 cc. of 4 % HC 1 (= o*i8 %). After 2 hours’ digestion, No. 1 gave a distinct tryptophane- reaction ; Nos. 2 and 3 a marked reaction, rather stronger in 3 than in 2 : after 22 hours’ digestion, No. 1 gave a marked reaction, No. 2 a very strong, and No. 3 a strong reaction. Pyrus Malus. The not quite ripe apple used was a variety of Codlin. The expressed juice is a greenish, acid liquid, which turns bright yellow on the addition of chlorine-water, the colour gradually deepening to orange. After 23 hours’ digestion with some Witte-peptone, there was no definite tryptophane-reaction. I then tried an experiment with bruised pieces of the parenchyma of the fruit, but with the same negative result. I was, however, more successful with the peel or rind. 3 grms. of rind were placed in each of two bottles with about 40 cc. distilled water: to the one nothing was added, to the other 0-3 grm. of Witte-peptone. After 19 hours’ digestion, the liquid in the bottle containing no Witte-peptone gave a bright yellow colour on the addition of chlorine-water, but no tryptophane-reaction : that in the bottle to which Witte-peptone had been added gave a distinct reaction. 246 Vines —Proteolytic Enzymes in Plants . Pyrus communis. The variety of Pear used was the Beurrd Hardi. 20 grms. of crushed, ripe, pear were placed in each of two bottles (40 cc.), filled up with chloroform-water: to No. 1 nothing was added : to No. 2 , 0-5 grm. Witte-peptone. After 4 hours’ digestion, No. 2 gave a faint tryptophane-reaction; No. 1, no reaction : after 24 hours’ digestion, No. 2 gave a distinct reaction ; and after 48 hours, a marked reaction : No. 1 gave no reaction. Citrus Aurantium. I found that whereas the rind acts on Witte-peptone, the juice of the Orange is without effect. In each of two bottles (45 cc.) were placed 5 grms. of orange- peel : both were filled with 50 % chloroform-water, and to the one (No. 2) 0-3 grm. of Witte-peptone was added. In each of two other similar bottles (3, 4) were placed 20 cc. of juice, and they were filled up with chloroform- water : to No. 4, 0-3 grm. of Witte-peptone was added. After 24 hours’ digestion, No. 1 gave a faint tryptophane-reaction ; No. 2, a strong reaction; No. 3, no reaction; No. 4, a scarcely perceptible reaction. Viiis vinifera. 55 cc. of juice and pulp of some ripe White Grapes (hothouse) were placed in each of two bottles, Nos. 1 and 2 ; the material in No. 2 had been previously boiled: to each, 35 cc. of chloroform- water were added, and 0*5 grm. of Witte-peptone. After 22 hours’ digestion, No. 1 gave a marked tryptophane-reaction; No. 2, no reaction. Similar, but less striking results, were given with quite ripe Black Grapes. Laticiferous Plants. In view of the fact that the latex of the Papaw ( Carica Papaya) and that of the Fig ( Ficus Carica) are known to contain proteases, I tried a few experiments with other latici- ferous plants. Vines . — Proteolytic Enzymes in Plants . 247 Euphorbia Characias. The latex from green herbaceous shoots is slightly acid, and gives no tryptophane-reaction. An extract was made by grinding up some shoots (without leaves) with distilled water. About 25 cc. of the extract were placed in each of three bottles : to No. 1 nothing was added ; to No. 2, a few drops of 4 % HCN; to No. 3, a few drops of HCN and 0*25 grm. of Witte-peptone. After 5 hours’ digestion, No. 3 gave marked tryptophane-reaction ; Nos. 1 and 2 gave none: 17 hours later, the reaction was strong in No. 3, doubtful in No. 1, absent in No. 2. Lactuca saliva. The bruised leaves of the Lettuce were used : 10 grms. of bruised leaf were placed in each of four bottles filled with distilled water (40 cc.) ; to No. 1 nothing was added ; to No. 2, 1 cc. of 4 % HCN ; to No. 3, 0-3 grm. of Witte-peptone ; to No. 4, 0*3 grm. of Witte-peptone and 1 cc. of 4 % HCN. After 3 hours in the incubator, no tryptophane-reaction was given in any case : 18 hours later, a faint reaction was given by Nos. 1 and 2, a strong reaction by No. 3, and a marked reaction by No. 4. Some experiments were made with the root and leaf of the Dande- lion : but the liquids became so deeply coloured that the tryptophane- reaction was uncertain. The measure of success that had been met with in the experiments with fruits and with laticiferous plants suggested to me the possibility of obtaining similar results with the stems, leaves, and roots of ordinary plants, which I accordingly proceeded to investigate. Stems. The material employed was either pieces of stem bruised in a mortar, to which about 40 cc. of distilled water were added, or the expressed juice of the stem in the same quantity. Dahlia variabilis. 5 grms. of bruised stem were placed in each of five bottles : to No. 1, nothing was added but 35 cc. of distilled water ; to No. 2, was 248 Vines . — Proteolytic Enzymes in Plants. further added 1 cc. of 4 % HCN; to No. 3, 0-3 grm. of Witte- peptone; to No. 4, 0*3 grm. of Witte-peptone and 1 cc. of HCN; in No. 5 the stem was boiled in the water before the addition of 0-3 grm. of Witte-peptone. After 24 hours’ digestion. No. 4 gave a distinct tryptophane- reaction: the liquid in No, 3 had become so darkly coloured that it could not be satisfactorily tested : none of the others gave any reaction. Cucurbita Pepo var. ovifera . The shoots of the Vegetable Marrow yielded, on pressure, a con- siderable quantity of turbid, slightly acid, juice. Some of this was placed in each of four bottles: to No. 1, nothing was added; to No. 2, o*5 grm. of Witte-peptone; to No. 3, 0*5 grm. of Witte-peptone and o-2 grm. of citric acid; to No. 4, 0*5 grm. of Witte-peptone and HC 1 to o-2 %. After 22 hours’ digestion, Nos. 1 and 2 gave a faint tryptophane-reaction, No. 3 a marked, and No. 4 a distinct reaction. Mirabilis Jalap a. Three bottles containing expressed juice were treated as follows : to No. 1, nothing was added; to No. 2, 0*3 grm. Witte-peptone; to No. 3, 0-3 grm. Witte-peptone and 1 cc. of HCN. After 20 hours’ digestion, No. 1 gave a faint, and Nos. 2 and 3 a distinct tryptophane-reaction. Similar results were obtained with Helianthus tuberosus. Cuscula , sp. The special interest of this experiment lies in the fact that the plant is a parasite, and that its leafless shoots contain no chlorophyll. A quantity of the shoots of a species, in flower, growing on some plants of Artemisia, was ground up fine: 40 grms. of this material were extracted with 40 cc. of distilled water. On pressure, a dark- brown acid liquid was obtained, which gave no tryptophane-reaction. 20 cc. of the unfiltered liquid were placed in each of two bottles : to each a few drops of 4 % HCN were added, and to one of them (2), 0*5 grm. of Witte-peptone. After 20 hours’ digestion, bottle No. 1 gave no tryptophane- reaction : bottle No. 2 gave a distinct reaction. Vines. — • Proteolytic Enzymes in Plants . 249 Leaves. The material used consisted usually of the tissue of the blade bruised in a mortar ; the petioles and mid-ribs were excluded as far as possible. Spinacia oleracea. In each of four bottles were placed 10 grms. of bruised Spinach leaves, and they were then filled with distilled water: to No. 1, nothing was added ; to No. 2, 1 cc. of HCN, 4 % ; to No. 3, 0-4 grm. of Witte-peptone ; to No. 4, 0-4 grm. of Witte-peptone and 1 cc. of HCN. After 18 hours’ digestion, No. 1 gave a distinct and No. 2 a faint tryptophane-reaction ; No. 3 gave a strong reaction, but as it had an offensive smell, the reaction may be attributed to putrefaction; No. 4 gave a marked reaction. Similar results were obtained with the leaves of the Dahlia, of Mirabilis, of Tropaeolum majus, of the Cherry-Laurel ( Prunus Lauro- cerasus), of Ricinus communis , of Helianthus tuberosus , and of Pelar- gonium zonale. Bras sic a oleracea. The results obtained with the leaves of the Cabbage were suffi- ciently striking to justify special mention. About 40 cc. of a watery extract of the leaves were placed in each of four bottles: to No. 1, nothing was added; to No. 2 , 1 cc. of 4 % HCN ; to No. 3, 0-4 grm. of Witte-peptone ; to No. 4, 0-4 grm. of Witte-peptone, and 1 cc. of HCN. After 4 hours’ digestion, No. 1 gave a distinct tryptophane- reaction ; in No. 2 the reaction was rather stronger ; in No. 3 it was marked, and strong in No. 4. Holcus mollis. In this case some stem was mixed with the leaves. 5 grms. of the bruised material were placed with 0-3 grm. of Witte-peptone in each of three bottles : to No. 1 distilled water only was added (40 cc.) ; the material and the water were boiled before being placed in No. 2 ; to the water in No. 3, HCN was added to 0-18 %. After 18 hours in the incubator, No. 1 gave a strong tryptophane-reaction, but smelt rather offensively ; No. 2 gave no reaction ; No. 3 a marked reaction. 250 Vines. — Proteolytic Enzymes in Plants. The only other Grass that I have investigated so far is Phalaris canariensis , and it gave even more definite results than Holcus. Apium graveolens. I experimented with the Celery with the special object of ascer- taining whether or not the green leaf-blades and the etiolated petioles would give concordant results : I found this to be the case. Experiment 1. — 10 grms. of bruised green leaf-blades were placed in each of three bottles (40 cc.), together with 0-3 grm. of Witte- peptone : No. 1 was filled up with chloroform-water (0-5 %) ; No. 2 was filled with distilled water that had been boiled with the leaf- material before the Witte-peptone was added ; No. 3 was filled with o* 1 % HCN. After 22 hours’ digestion, No. 1 gave a marked tryptophane-reaction, and No. 3 a strong one; No. 2 gave no reaction. Experiment 2. — 10 grms. of bruised etiolated petioles were placed in each of three bottles, the other contents of which were precisely the same as in the preceding experiment. After 5 hours’ digestion, No. 1 gave a distinct, and No. 3 a faint, tryptophane-reaction; after 23 hours’ digestion the reaction in No. 1 was strong, marked in No. 3, and faint in No. 2. Scolopendrium vulgare. An experiment with the leaves of the Hart’s Tongue Fern, as representing the Pteridophyta, is of peculiar interest. 5 grms. of bruised leaf were placed in each of three bottles (40 cc.) ; to each 0*3 grm. of Witte-peptone was added, and the bottles were filled up with distilled water ; the leaf in No. 2 had been boiled before being placed in it; to No. 3, 1-5 cc. of 4 % HCN were added. After 24 hours’ digestion, slight indications of the tryptophane- reaction were given by Nos. 1 and 3; after 42 hours’ digestion, No. 1 gave a strong reaction, and had an offensive smell; No. 2 gave no reaction ; No. 3 a marked reaction. Bulbs. Experiments were made with the Tulip, the Hyacinth, and the Onion, the material used being pieces of the bulbs. Tulipa , sp. 5 grms. of bulb in each of three bottles (45 cc.) : all three were filled up with chloro form- water ; the bulb-material in No. 2 had Vines, — Proteolytic Enzymes in Plants. 251 previously been boiled ; to No. 3, 0-3 grm. of Witte-peptone was added. After 22 hours’ digestion, No. 1 gave a distinct tryptophane-reaction ; No. 2 no reaction ; No. 3 a marked reaction. Precisely similar results were obtained with the Hyacinth ( Hyacin - thus orientalis), and with the Onion ( Allium Cepa) : the expressed juice of the onion gives a marked tryptophane-reaction. Tubers. Solarium tuberosum . 5 grms. of the cortical tissue of a potato were placed in each, of two bottles, 1 and 2, that in 2 having been previously boiled : to each 0-3 grm. of Witte-peptone was added, and both were filled up with chloroform-water (about 50 cc.). After 24 hours’ digestion, No. 1 gave distinct tryptophane-reaction, No. 2 no reaction. Similar results were obtained with the tuber of the Jerusalem Artichoke (. Helianthus tuber osus). Roots. Experiments were made with the roots of the Tomato, the Vegetable Marrow, and the Scarlet Runner : as also with the tuberous roots of the Turnip, the Carrot, the Beet, and Mirabilis Jalapa . Brassica Rapa. The expressed juice of the turnip gives distinct tryptophane- reaction. 30 cc. of the juice were placed in each of two bottles: to No. 1, nothing was added; to No. 2, 0-3 grm. of Witte-peptone and 1-5 cc. of 4 % HCN (= o*i8 %). After 7 hours’ digestion, No. 1 gave the same tryptophane-reaction as at first, No. 2 gave a strong reaction. Similar results were obtained with the other roots, either the bruised root or a watery extract being used. I have so far obtained evidence of the proteolysis of Witte- peptone by all the vegetable substances employed, with the exception of the pulp and juice of the Apple and of the Orange. Proteolysis seems to be effected almost equally well when the reaction of the liquids is alkaline (0-5 °/ o 252 Vines. — Proteolytic Enzymes in Plants. Na 2 C 0 3 ) as when it is acid. Experiments in alkaline medium were performed with leaves of Lettuce, Spinach, and Celery ; the tuber of the Potato ; the bulbs of the Tulip and the Hyacinth ; the fruit of the Banana and of the Orange (peel). Experiments with Proteids other than WlTTE-PEPTONE. Inasmuch as nearly all the proteases known at the time when I commenced my experiments had been found to be peptonizing as well as proteolytic, it was incumbent upon me to ascertain whether or not the newly discovered proteolytic enzymes were also capable of peptonizing the higher proteids. I therefore proceeded to test some of them with such proteids as fibrin, raw egg-albumin, caseinogen (as contained in milk), and commercial casein. Fibrin. Experiments were made with the following: the juice of the Melon, the Vegetable Marrow, the Cucumber, the Tomato, the Onion ; extract of Euphorbia Characias , and of Wheat- Germ ; bruised leaves of Spinach and of Celery (etiolated) ; the bruised tissue of the Mushroom. The well-washed fibrin used had been preserved in dilute glycerin. The possible tests for digestion were (1) the biuret-reaction; (2) the trypto- phane-reaction ; (3) the disappearance of the fibrin supplied. In many cases (especially leaves) the biuret-test could not be applied on account of the presence of a substance that gave a strong yellow colour on the addition of the concentrated NaHO solution. Nor was the tryptophane-test alone al- together reliable, since the reaction might be the result of the digestion of proteids in the juice or tissue under examination, but together with the disappearance of the fibrin it could be depended on. The following instances illustrate the general methods of experiment. Cucumis sativus. 50 cc. of the expressed juice of a nearly ripe, somewhat yellow Cucumber were placed in each of two bottles ; to each was added Vines. — Proteolytic Enzymes in Plants. 253 0*5 grm. of moist fibrin, and to (1) HC 1 to 0*2 %, to (2) citric acid to 1 %. After 24 hours’ digestion, the fibrin had disappeared in (1), and there was but little left in (2). The juice gave marked tryptophane-reaction to begin with. In a second experiment, a green, quite unripe Cucumber was used : the juice gave no tryptophane-reaction. 50 cc. of juice were placed in each of two bottles with 1 grm. of moist fibrin: (1) was acidified with HC 1 to 0-2 %; (2) with citric acid to o*5 %. A third bottle (3) contained only juice. After 2 hours’ digestion, the contents of (1) and (3) gave a marked tryptophane-reaction ; those of (2) a distinct reaction : this is clearly due to the digestion of the proteids of the juice. After 24 hours’ digestion, the fibrin in (i) and (2) had perceptibly diminished; after 48 hours it had disappeared in (1), and there was very little left in (2). Euphorbia Characias. A watery extract was made of the soft parts of some stems, without leaves : the extract gave no tryptophane-reaction. 30 cc. of the extract were placed in each of four bottles: to (1) nothing was added, to the other three 0-5 grm. of moist fibrin; (3) was acidified with HC 1 to o-2 % ; (4) with citric acid to 1 %. After 18 hours’ digestion, (1) and (2) gave a distinct, (3) a marked, and (4) a strong tryptophane-reaction; in (2), (3), and (4) the fibrin had diminished. After 45 hours’ digestion, there was still a little fibrin left in (3), and rather more in (2) and (4); all three gave a strong tryptophane-reaction, whilst that of (1) had remained distinct. Wheat- Germ. 5 grms. of finely ground ‘germ’ were extracted with 100 cc. dis- tilled water: the extract gave no tryptophane-reaction. 50 cc. of extract were placed in a bottle (1) with 0*25 grm. moist fibrin, and acidified with HC 1 to o-i % ; 20 cc. of extract were placed in another bottle (2), nothing being added. After 23 hours’ digestion, the fibrin in (1) was found to have diminished, and the liquid gave distinct tryptophane-reaction ; the liquid in (2) gave a faint reaction. After 28 hours’ digestion, the fibrin had disappeared in (1), which now gave a marked tryptophane- reaction ; (2) gave a distinct reaction. 254 Vines.— Proteolytic Enzymes in Plants. Cucumis Melo. 25 cc. of Melon juice and 20 cc. of chloroform-water were placed in each of two bottles: to No. 1, nothing was added; to No. 2, o*2 grm. of moist fibrin; a third bottle contained 45 cc. of pure juice and 0-2 grm. of fibrin. After 22 hours’ digestion, No. 1 gave a distinct tryptophane- reaction ; No. 2, a marked reaction, the fibrin being much broken up ; No. 3, a marked reaction, and the fibrin had altogether dis- appeared. Agartcus campestris. 5 grms. of bruised Mushroom were placed in each of two bottles, with 20 cc. chloroform-water and 20 cc. distilled water: to No. 2, 0-3 grm. moist fibrin was added. After 22 hours’ digestion, No. 1 gave a distinct tryptophane- reaction ; No. 2 a marked reaction ; most of the fibrin had been dissolved. I failed to obtain similar evidence of the digestion of fibrin in experiments with the fruits of the Vegetable Marrow, the Tomato and the Orange (rind and juice) ; the bulbs of the Onion, the Tulip, and the Hyacinth ; the leaves of Spinach and of Celery ; when the liquid was naturally or artificially acid. But when the liquid was rendered alkaline by Na 2 COs, digestion was effected by the bulbs of the Tulip and the Hyacinth. 5 grms. of bruised Tulip bulb were placed in each of two bottles, both of which were filled up with 40 cc. of chloroform-water: to No. 1, nothing was added; to No. 2, 0*2 grm. of both moist fibrin and Na 2 C 0 3 . After 24 hours’ digestion, No. 1 gave a distinct tryptophane-reaction; No. 2 gave a marked reaction, as also good biuret-reaction, and the fibrin had disappeared. Similar experiments with Orange-peel, leaves of Spinach and Celery, and fruit of Banana, extending to 48 hours, gave no evidence of digestion. On the other hand, in that time digestion was effected by Hyacinth-bulb. Albumin and Casein. Only a few experiments were made with albumin. The form in which it was used was a 50 °/ o watery solution Vines. — Proteolytic Enzymes in Plants. 255 of raw white-of-egg. The vegetable material was Cucumber (green), Mushroom, leaves of Tropaeolum and Lettuce, and the root of the Carrot. In only one instance, that of the Mushroom, was there distinct evidence of digestion. 5 grms. of bruised Mushroom were placed in each of two bottles with 40 cc. of dilute (50 %) chloroform-water: to No. 1, nothing further was added ; to No. 2, 5 cc. of the albumin-solution. After 24 hours’ digestion, No. 2 gave marked biuret and tryptophane - reactions ; No. 1 gave no biuret, but distinct tryptophane. Two samples of casein were used : ‘ commercial ’ and ‘ pure’ casein. In two instances, the Melon and the Mushroom, the casein was undoubtedly digested, whilst in others the result was negative. 25 cc. of Melon-juice, with 25 cc. of chloroform- water, were placed in each of two bottles : to No. 1, nothing was added; to No. 2, 0-3 grm. of pure casein. After 22 hours’ digestion, No. 2 gave a strong tryptophane-reaction; No. 1 gave a distinct reaction, as it did at the commencement of the experiment. A similar experiment with the Mushroom gave essentially the same result. I failed to obtain evidence of digestion of casein by the Cucumber, the leaves of Phalaris and Tropaeolum , or by Orange-peel. It occurred to me that although casein had proved to be relatively indigestible, yet the caseinogen of milk might prove to be more tractable, and this I found to be the case in several instances. Since the Mushroom and the juice of the Melon had been found to digest casein, it was a foregone conclusion that they would also digest the caseinogen of milk. 15 cc. of Melon-juice, with 20 cc. of chloroform-water, were placed in each of three bottles, Nos. 1, 2, 3 ; the juice in No. 2 had pre- viously been boiled; “to No. 1 and 2, 15 cc. of skim-milk were added, to No. 3, 15 cc. of distilled water. After 24 hours’ digestion, No. 1 gave a very strong tryptophane-reaction ; No. 2, no reaction ; No. 3, a faint reaction. 256 Vines. — Proteolytic Enzymes in Plants . Similar results were obtained with the Mushroom, 5 grms. of the solid substance being used. Less marked evidence of digestion of milk was obtained with Orange-peel, and with the bulbs of the Tulip and the Hyacinth, as also with the Banana. No digestion was ob- served with the Turnip, the Vegetable Marrow, the Pear, the Apple, with the leaves of the Cabbage, the Lettuce, and the Spinach, or with the ‘milk’ of the Coco-nut, in 19 hours. These experiments generally included a control-bottle con- taining the mixture of chloroform-water and milk, without any vegetable substance at all : in no case did the contents of the control give any trace of tryptophane-reaction. Tryptophane in Plants. It will have been observed that, in the foregoing account of the experiments, mention is incidentally made of the presence of tryptophane in the expressed juices or in the watery extracts of plants : for instance, in the case of the Banana, the Melon, the yellow (but not the green) Cucumber, the Vegetable Marrow, the Tomato, among fruits ; of the bulb of the Onion (strong), and of the root of the Turnip. I have not found it in the juice of the Orange, the Apple, or the Grape, nor in extracts of the tubers of the Potato and the Jerusalem Artichoke, of Green Peas, of Wheat-Germ, or of any of the shoots or leaves mentioned. I have made a few further observations upon the occurrence of this substance, and have found it in the ‘ milk ’ of the Coco-nut ; in extracts of seedlings of the Bean ( Vicia Faba) 2-3 inches in height, of the Scarlet Runner (. Phaseolus maltiflorus ) 6-8 inches in height, and of the Pea (. Pisum sativum ) a foot high, excluding the cotyledons in all cases. I have not found it in seedlings of the Maize, apart from the seed : nor in the shoots of the Asparagus, nor in etiolated shoots produced by germinated tubers of the Potato and of the Jerusalem Artichoke, though it was present in the potato- shoots after they had turned green in consequence of exposure to light. Vines. — Proteolytic Enzymes in Plants. 257 These facts are insufficient to suggest any general explana- tion of the conditions of the formation of tryptophane in the plant-body. In the case of fruits, its presence is certainly associated with the process of ripening ; in the case of seedlings, with the presence of a supply of reserve proteid. Inasmuch as tryptophane is a product of catabolism, the detection of it in the tissues may serve as a means of deter- mining the exact seat of these processes and the conditions under which they take place. Oxidase and Enzyme. If tincture of guaiacum be treated with an oxidizing agent, such as chlorine-water or potassium permanganate (KMn0 4 ), it is oxidized and assumes a deep blue colour. It was ascertained by Schonbein (5) and others that various vege- table substances, for instance, roots, stems, leaves, and flowers of the Dandelion (Leontodon Taraxacuiri), the rind of the potato, &c. similarly effect the oxidation of guaiacum at the expense of the oxygen of the air. More recently, Bertrand (6) has found that the reaction is induced by many parts of plants — the roots of the Beet, the Carrot, the Turnip, and the Dahlia ; the shoots of the Asparagus ; the rhizome of Canna ; the stems and leaves of Lucerne, Clover, and Rye-Grass ; the leaves of the Jerusalem Artichoke (Helianthus tuber o sits'), and of the Beet ; the fruits of the Apple, the Pear, and the Quince ; the petals of Gardenia ; the latex of species of Rhus ; and he has also ascertained that the reaction is due to the presence of an extractable organic substance that may be generally termed oxidase. Schonbein further observed that portions of plants that cannot induce the direct oxidation of guaiacum can do so indirectly, if a small quantity of hydrogen peroxide (H 2 0 2 ) be present, the oxidation being effected by the oxygen set free on the decomposition of the H 2 0 2 . This property, indicative of a lower degree of oxidative activity, is very commonly possessed by plants, and attaches to a substance distinguished as peroxidase. s 258 Vines . — Proteolytic Enzymes in Plants . It is probable that peroxidase is a modification of oxidase. Schonbein observed that if the watery extract of a part of a plant giving the oxidase-reaction with guaiacum be allowed to stand for some hours, it loses this property, but is still capable of oxidizing guaiacum in the presence of H 2 0 2 . The converse change has not yet been effected. Moreover, a substance or liquid giving the oxidase-reaction also gives the peroxidase-reaction. With these facts in mind, I took the opportunity of applying the guaiacum-test, in one form or other, to all the various parts and juices of plants that I employed in the digestion- experiments. I found that, with a few exceptions, they all gave either the oxidase- or the peroxidase-reaction. My results are as follows. Oxidase-reaction : given by tissue and watery extract of the Mushroom ; extract of Cuscuta shoots ; tissue of the Pear ; rind of the Apple, the pulp only when quite ripe ; cortex of tuber of Potato ; tuber of Helianthus tuberosus ; root of Dande- lion ; feebly by the root of the Carrot ; ripe Grapes (especially black) ; watery extract of leaves and stems of the Lettuce. Peroxidase-reaction : given by the juice of the Melon, Cucumber, and Vegetable Marrow ; the tissue, but not the juice, of the Tomato ; the latex of Euphorbia Characias ; the milk of the Coco-nut ; extract of Green Peas ; extract and root of the Turnip ; the tissue of the bulb of the Onion, the Tulip, and the Hyacinth; the rind (but not the pulp or the juice) of the Orange; Wheat-germ; the pith of the Potato-tuber ; the tissue of the ripe Banana and of the Beet- root ; all the non-laticiferous leaves investigated. None of these gave the oxidase-reaction. It will be seen that my results do not exactly agree with those of Bertrand. The divergence is, I believe, due probably to seasonal differences in the condition of the parts examined. It is at any rate clear that the nature of the reaction given by fruits depends upon the degree of ripeness. So far as I am aware, there is at present no satisfactory explanation of the physiological significance of the presence Vines. — Proteolytic Enzymes in Plants. 259 of oxidases and peroxidases in plants. I cannot presume to offer one now, as I have merely glanced at the subject. But I have observed a fact that seems to be worth recording and bears directly upon it : — it is that when I have found a liquid or a tissue to give a good reaction with guaiacum, whether with or without H 2 0 2 , I have also found it to be proteolytic ; whereas, when its guaiacum-reaction is wanting, it is deficient in proteolytic activity. For instance, having observed that neither the juice nor the pulp of the Orange gave any guaiacum-reaction, whilst the peel gave a strong peroxidase- reaction, I found the peel to be actively proteolytic but not the juice or the pulp (see p. 246). Exactly the same occurred in the case of the Apple (see p. 245). Again, the pulp of some white Spanish grapes slowly gave a faint peroxidase- reaction, and was found to have little proteolytic action on Witte-peptone: some fully-ripe English hot-house grapes, on the contrary, both white and black, gave the oxidase-reaction and digested Witte-peptone. The association of these oxidizing substances with enzymes may be only a coincidence, or it may indicate a relation between oxidative and enzymotic activity. It is one that has already attracted attention, for it was thought at one time that the enzymes themselves reacted with guaiacum. But this is not the case: papain, for instance, gives no reaction. Assuming, as seems more probable, that co-existence means correlation, it is not an impossible suggestion that oxidase or peroxidase may be concerned with the formation of the enzyme, whether protease, glucase, lipase, &c. : that, for instance, their oxidative action may determine the liberation of the enzyme from its zymogen. This suggestion may perhaps supply the true physiological interpretation of Raciborski’s ( 7 ) important observation that the sieve-tissue of plants gives the peroxidase-reaction, as also of the fact that the reaction is likewise given by latex. The latex of the Papaw and of the Fig is known to actively digest proteids ; and my observations on Euphorbia Characias and on the Lettuce (p. 247) indicate that this is true of 260 Vines.- — Proteolytic Enzymes in Plants. these plants also. The marked proteolytic activity of the Cucurbitaceae, of which I have given several instances, taken in connexion with the great development of the sieve- tissue in plants of this Order, suggests that the proteases are specially located in this tissue. This being so, there would seem to be a definite relation between the oxidative and the digestive properties of the contents of the laticiferous and sieve tissues. Concluding Remarks. The experiments previously described suffice to prove that the juices or the tissues of various parts of the most widely different plants so act on certain proteids, whether contained in them or added to them, as to give rise to a substance giving a reaction similar to that of tryptophane with chlorine- water. It has been tacitly assumed throughout that the substance in question is actually tryptophane: but inasmuch as the conclusions to be drawn entirely depend upon it, it is neces- sary that the assumption should be justified. I have not, I admit, isolated the substance, and so placed the matter beyond doubt ; that is a task that could only be successfully undertaken by a professed physiological chemist ; but I am able to adduce other convincing evidence. It is known that if a liquid, which has given the tryptophane-reaction, be shaken up with some amyl alcohol, the pink chlorine-compound dissolves in the alcohol which separates out as a supernatant layer coloured pink. If this coloured solution be examined spectroscopically, the spectrum is found to present a well- marked absorption-band in the green, on the yellow side of the Thallium-line (571-540 /qx). I have applied this test with success to several of the digestion-liquids, and have in all cases found that the chlorine-compound dissolves in amyl alcohol, and that the pink solution gives the absorption-band characteristic of the chlorine-compound of undoubted trypto- phane. I conclude, therefore, that the substance which gave Vines.— Proteolytic Enzymes in Plants. 261 the tryptophane-reaction in my experiments is actually the chemical substance known as tryptophane. The formation of tryptophane in the experiments leads to the further conclusion that proteolysis must have taken place, for the presence of this substance is evidence of proteolysis. Hopkins and Cole (8) have* shown that tryptophane is either an indol-amido-propionic acid, or a skatol-amido-acetic acid : in either case it cannot be regarded as other than a product of the disruption of the proteid molecule. The experiments therefore prove that the various vegetable substances employed effected proteolysis. Inasmuch as it took place in the presence of antiseptics, such as HCN and chloroform-water, the chemical action cannot be attributed to micro-organisms. On the contrary, it is to be ascribed to a proteolytic enzyme contained in the juices or the tissues themselves. If this be so, then I have succeeded in demonstrating that a proteolytic enzyme is widely distributed in plants ; and it may be inferred that it is much more generally present than I have shown it to be. If it is present in plants belonging to the Chenopodiaceae, the Nyctaginaceae, the Euphorbiaceae, the Cruciferae, the Geraniaceae, the Ampelidaceae, the Rosaceae, the Leguminosae, the Umbelliferae, the Cucur- bitaceae, the Compositae, the Liliaceae, the Graminaceae, and the Musaceae, there is no reason why it should not equally be found in plants of other Natural Orders. Nor is it by any means confined to Phanerogams. I have demonstrated its presence in the Mushroom, among the Fungi ; and in the Hart’s Tongue Fern, among Pteridophyta. I confidently anticipate that it will be duly discovered in the remaining groups of Cryptogams, the Bryophyta and the Algae. The next point to be considered is the probable nature of the enzyme. In the previously known cases, the Pine-Apple, the Papaw, the Fig, Nepenthes , Yeast, Bacteria, and seeds, the evidence goes to prove, as I have explained in the paper (1) already mentioned, that the enzymes are allied to the trypsin of animals, since they both peptonize and proteolyse actively. 262 Vines. — Proteolytic Enzymes in Plants. Amongst the plants that I have examined, there are only two, the Melon and the Mushroom, that contain enzymes which approach those just mentioned in their power of peptonization and proteolysis. Whilst all the others readily proteolysed Witte-peptone, their action on the higher pro- teids, so far as it was tested, was relatively feeble and in some cases altogether wanting. It may be that the precise condi- tions favourable for peptonization were not afforded in the experiments: that is a point for future investigation. But taking the facts as they stand, it is an inevitable conclusion that if in some cases, such as the Melon and the Mushroom, the enzyme may be regarded as a vegetable trypsin, this view cannot be extended to the others. It seemed to me, at first, that I had come upon an altogether new type of enzyme, an idea that occasioned a certain amount of temporary misgiving as to the accuracy of my observations. But it was pointed out to me by my colleague Professor Gotch, that within the last year Cohnheim (9) has described an enzyme, formed in the mucous membrane of the small intestine, which actively proteolyses peptone and casein but does not act upon the higher proteids. It is to this enzyme, termed ‘erepsin’ by Cohnheim, that the apparently new proteolytic enzyme of plants would correspond. It would appear, therefore, that plants form two distinct kinds of proteases, the one a trypsin, the other an erepsin ; and so far as the facts go, they indicate that the former is generally associated with depositories of proteid nutriment, such as seeds, fruits, bulbs, laticiferous tissue, &c., the latter with ordinary foliage-leaves, stems, and roots. But further research is required in order to definitely establish this distinction. I cannot too strongly emphasize the point that the results detailed in this paper must be taken as applying only to the particular season of the year during which the experiments were made ; that is from August to November. I have noticed that even within this period certain variations pre- sented themselves. The investigation of the various parts of plants, especially of leaves, at different times of the year, will Vines. — Proteolytic Enzymes in Plants. 263 certainly yield a great deal of additional information. My observations on fruits indicate that the digestive activity, both peptonizing and proteolysing, is greatest when they are fully ripe, a condition that may be regarded as the first stage of decay. It would be premature at present to attempt any minute discussion of the physiological significance of the wide dis- tribution of a proteolytic enzyme in the body of the plant : it is obvious that what has hitherto been regarded as exceptional, must now be recognized as the rule, and this must profoundly affect many physiological conceptions. The most interesting point is that, in respect of their distribution, the proteases are now brought into line with the enzymes which are concerned with the carbohydrate metabolism of the plant. Just as diastase was, step by step, discovered to be everywhere present in the body of the plant, so now the same has been done for the proteolytic enzyme. No doubt the analogy also holds good with regard to their respective functions. Just as diastase facilitates the transference of temporarily deposited starch, so the proteolytic enzyme renders possible the distribution of the elaborated proteids. It is remarkable that this obvious analogy should not already have led to a search for a generally distributed proteolytic enzyme : but the difficulties in detecting and following the proteids in the tissues, difficulties which do not exist in the case of starch and sugar, are no doubt the sufficient reason. In conclusion, I may further point out that the case of ‘ insectivorous ’ plants no longer stands alone. If leaves generally, or at any rate commonly, produce a proteolytic enzyme, it ceases to be remarkable that a similar enzyme should be formed by the leaves of certain of the ‘insecti- vorous * plants. The peculiarity of these plants is now limited to this — that their enzyme should be poured out at the surface, so that it digests proteids supplied from without by the captured insects ; whereas in ordinary plants the enzyme is retained within the tissue to digest, and so to render mobile, the proteids that are formed there. 264 Vines . — Proteolytic Enzymes in Plants . List of References. 1. Vines: Tryptophane in Proteolysis; Annals of Botany, vol. xvi. March, 1902, p. 1. 2. Beyerinck : Culturversuche mit Zoochlorellen etc. ; Bot. Zeitg., 1890. 3. Vines: Proteid Substances contained in Seeds; Journal of Physiology, vol. iii, 1881, p. 93. 4. Green : Vegetable Trypsin in the Fruit of Cucumis utilissimus ; Ann. Bot., vol. vi, 1892, p. 195. 5. Schonbein : Katalytische Wirksamkeit organischer Materien ; Journ. Prakt. Chemie, Bd. lxxxix, 1863, p. 323. 6. Bertrand: Recherche et presence de la laccase dans les vegetaux; Comptes rendus, t. cxxi, 1896, p. 166. 7. Raciborski: Ueber Leptomin; Ber. d. deutsch. Bot. Ges., Bd. xvi, 1898, p. 52 and p. 1 19. 8. Hopkins and Cole : Chemistry of Proteids ; Journal of Physiology, vol. xxvii, 1901, p. 418. 9. Cohnheim : Die Umwandlung des Eiweisses durch die Darmwand ; Zeitschr. f. physiol. Chemie, Bd. xxxiii, 1901, p. 451; Trypsin und Erepsin, ibid. Bd. xxxvi, 1902, p. 13; Weitere Mittheilungen iiber das Erepsin, ibid. Bd. xxxv, 1902, p. 135. NOTES. NOTES ON THE HISTOLOGY OF THE SIEVE-TUBES OF CERTAIN ANGIOSPERMS.— In continuation of the researches on the sieve-tubes of Gymnosperms, which were published in the Annals of Botany, vol. xv, No. lx, December, 1901, the sieve-tubes of certain Angiosperms have been examined in detail by methods similar to those previously employed. The sieve-tubes of Vitis vinifera , Wistaria chinensis, Cucurbiia maxmia , Tilia europaea , and Viscum album have been studied with special reference to their ‘ connecting threads ’ and means of inter- communication, and they have been found to agree in their general characteristics and essential structure with the sieve-tubes of the several species of Pinus already described. In the mature sieve-tubes of these five plants, the end walls or sieve-plates are traversed by relatively large slime-strings, and each slime-string is enclosed in a callus-rod. In the radial and tangential walls slime-strings occur in groups in large or small shallow pits, and, except in the case of Viscum album , each of these groups, composed of some three to six fine slime-strings, is contained in a callus-rod. Such a group seen in surface view constitutes a ‘ sieve- field.’ The structure of these lateral sieves and sieve-fields is similar to that of the sieve-plates of Pinus sylvestris , &c. A median dot is usually visible on each thread. In Viscum album the lateral walls between two sieve-tubes are crowded with groups of fine threads in small shallow pits, but no callus-reaction is given by the cell-wall in their neighbourhood. Callus, however, does occur in the end-wall sieve-plates in connexion with the slime-strings. With the approach of winter, the callus-rods increase in size at their free ends, which unite to form callus-pads on both the end and side walls. The slime-strings perforate these callus-masses so as to unite the contents of adjacent sieve-tubes. [Annals of Botany, Vol. XVII. No. LXV. January, 1903.] 266 Notes . With the increase in thickness of the callus-masses the slime- strings become progressively attenuated, and in the case of those sieve-tubes which function for a year only the callus finally blocks up the pores leading from one sieve-tube to another. Connecting threads also occur in some abundance between sieve- tubes and other elements of the phloem. Between the sieve-tubes and their companion cells (as Gardiner and Hill had already observed) threads are very numerous and very short, for the cell-walls are furnished with a great number of deep pits elongated in the horizontal direction. Sieve-tubes are placed in communication with adjacent bast-paren- chyma cells by threads, which are in some cases fairly numerous and are usually short and occur in small and deep pits. Cells comparable in the structure of their threads to the albuminous cells of Pinus sylvestris , &c., apparently occur in the phloem of Vitis vinifera. In the cases just cited the groups of threads are covered in winter by callus-pads, which however are formed only on the sieve-tube side of the groups, and the connecting threads can usually be seen to traverse the callus-masses. It is interesting in this connexion to notice that sieve-tubes appear to be the only elements of the bast in which callus is formed. The development of the terminal sieve-plates is very difficult to investigate, owing to the thinness and delicacy of the pit-closing membrane, but the history of the lateral sieves can be more easily followed. The development of the sieves in the radial and tangential walls appears to be analogous to the development of the sieves in the radial walls of the sieve-tubes of species of Pinus , and the sieves in the radial and tangential walls of most Angiospermous sieve-tubes appear to pass through similar developmental stages to those which have been described for such Gymnosperms as Pinus. Groups of fine threads can be seen in the lateral walls of the youngest sieve- tubes, which by the action of ferments (as it would appear) are bored out and converted into slime-strings, the cellulose membrane in the immediate vicinity being at the same time altered into callus. In this way the callus-rod enclosing a small group of slime-strings is produced. All stages in the process have been seen. The precise mode of development of the end-wall sieve-plates has not yet been seen very Notes. 267 clearly. In the youngest stages there appear first to be small groups of threads in little secondary pits ; very soon little rounded and bason- shaped masses of callus arise in the little depressions on either side of the thin membrane, and these finally unite to form a short callus-rod. In Wistaria chinensis and in Vi/is vinifera three to five threads apparently of the nature of slime-strings have been seen in each callus-rod in sieve-plates of this age, but more detailed and careful examination is demanded before any conclusive statement can be made. In the next older tube the boring out of these strings has proceeded further, and given rise to the single slime-string in each callus-rod so characteristic of the mature terminal sieve-plates of Angiosperms. The views put forward to explain the origin of the callus in species of Pinus seem to apply with equal force in the present case : for the callus-rods appear to be formed by local alteration of the cell-wall, and to arise at first as cylindrical rods, which subsequently become hexagonal owing to growth and mutual pressure in the confined area of a pit. As to the further production of callus towards the end of the season, it would appear that the protoplasm of the sieve-tube commences to form callus, which not only builds up the callus-pads on the callus-rods of the terminal and lateral sieve-plates, but also deposits callus-substance around all the groups of threads which connect the sieve-tubes with other elements of the phloem. It has become clear during the progress of these researches that it is the slime-strings which are of primary importance to the sieve- tubes, and that the callus, though no doubt also playing an important role in the life-history of the sieve-tube, must be regarded as of altogether secondary importance, being for the most part subservient to the slime-strings and active or living sieve-tube contents, of which the slime-string itself is merely a continuation. King’s College, Cambridge, Nov . 11, 1902. ARTHUR W. HILL. * NOTE ON THE DISPERSAL OF MANGROVE SEEDLINGS.— During the year 1901 and for three months of the present year I was engaged in marine biological work for Sir Charles Eliot, K.C.M.G., H.B.M. Consul-General at Zanzibar and Commissioner for British East Africa. During all this time I was interested in, and at first much 268 Notes. puzzled, by the conditions under which I found mangroves growing in these regions. The coasts of the whole of British and German East Africa are composed of a hard coral limestone of peculiar properties. (For a full account of this see my papers in the Proc. Phil. Soc. of Cambridge, vol. ix, pt. vi, Part i, ‘ On the Coral Reefs of Zanzibar/) The erosion of the waves has cut down this rock so that at low-tide there is an almost perfectly plane surface of rock, sloping gradually from the base of the cliffs to low-water level. In creeks and sheltered places generally, near high-water mark, this rock plane is full of irregular small holes and crannies, but no loose stones or deposits, other than a very thin coating of fine mud, interrupt its uniformity. On this hard surface, sending their roots into the crannies, the greater number of the mangroves of Zanzibar flourish so well that a considerable trade is carried on from Chuaka Bay 1 in their stems. (These are used in the building of all the Arab and native houses of Zanzibar, being too hard for the jaws of the termites.) Only occa- sionally do we find mangroves growing in mud and see the demon- stration of the well-known method of planting, viz. by the impact of its fall forcing the root of the embryo into the mud. In the majority of cases one finds the embryo placed in one of the holes of the rock, which is usually of but slightly larger diameter than itself. Obviously it did not fall by chance into this position ; suitable holes are not so numerous, and the insertion of the radicle into them not so easy as this would imply. Moreover, I have often observed embryos neatly planted in these holes at a distance of more than a hundred yards from the shade of the nearest possible parent tree, and in a few cases at a distance of miles. How this planting could be done, except by human hands, remained for a long time a mystery to me. The solution came when I noticed the frequency with which I met embryos floating in the sea, being carried out of the bay by the strong tidal currents. Often I passed through fleets of them, as it were, all floating in the same peculiar way, viz. vertically, with the leaf-bud just projecting from the water. (See the figure.) A consideration of the shape of the radicle shows that not only is there a perfect adjustment of the specific gravity of the whole to that of the sea water, but a peculiar distribution of it in 1 A large and very shallow bay on the east coast of Zanzibar island, where most of my time was spent. Notes. 269 order that the thick end may sink, instead of floating uppermost, as it would if the specific gravity were the same throughout. Both kinds of embryo, the thick and the slender, float in the same way. On reaching shore the embryos are planted by the insinuation of the root-tip into any softness or crevice of the bottom by the falling tide. The figure represents a section of the rock of the shore across a crevice, which is full of mud, as shown by the dark shading. The vertical embryo is in the position in which it floats freely. The tide has fallen until its root-tip engages a projection on the bottom. The ripples will now cause its oscillation about the tip, which will thus be kept slowly boring down into any mud or crevice present as the 270 Notes . falling tide brings the weight of the embryo on to its point, until it has reached the position of the lower specimen in the figure. The success of this method depends upon the action of ripples of the water, but on an exposed shore the waves will merely throw the embryo about as any other floating stick. Suitably shaped and fairly numerous crevices in the rock are usually met with near high-tide mark, the surface of the flats lower down being smoother and its crevices too shallow, or filled in with hard sand. In short, the condi- tions requisite to planting are generally those suitable for the life of the adult trees, but, as in the case of other trees, those conditions are sometimes found where the embryo can never develop into the adult. Embryos are often planted too low down the shore (I have even met with one, bearing two unfolded leaves, at low tide in the sand of the boat channel of the reef on the open coast), but in this case they will be usually floated off again by succeeding tides. There are thus tivo adaptations of the mangrove, ensuring that, in the case of those trees which are growing in mud, too many embryos shall not be swept out to sea, and also that those which are so removed shall have a good chance of taking root in fresh localities. The mangrove has thus an effective means of dispersal, and it is probable that the juxtaposition of trees from different sources, whereby continued in-and-in fertilization is avoided, is just as important for them as for the great majority of living things. Furthermore, this adaptation for dispersal enables the embryos to be planted on surfaces to which the formerly known method is inapplicable. CYRIL CROSSLAND. Cambridge. EXPLOSIVE DISCHARGE OF ANTHEROZOIDS IN FEGA- TELL A CONIC A. — Fegatella ( Conocephalus ) conic a is one of the commonest liverworts in the neighbourhood of Leeds. It grows in great abundance in moist and shaded places, especially on stones beside streams. In the beginning of July a large supply of male plants was collected, bearing young antheridial receptacles, which, as is well known, are sessile in this genus, and have the form of oval cushions, each situated at the anterior end of one of the branches of the thallus. Most of these plants were put into shallow vessels, covered with sheets of glass, and set in a shaded place. After a few Notes. 271 days the plants were examined for the purpose of selecting material to show the development of the receptacles, and whilst looking over them in bright sunlight the writer observed a number of jets of fine spray arising from the upper surface of the plants. On closer exami- nation it was found that in every case these jets, which issued in an explosive manner and sometimes reached a height of above two inches, proceeded from the little conical prominences with which the upper surface of the male receptacle is studded. On holding a glass slide a little above the surface of a receptacle and catching the spray as it escaped, it was found that it consisted of water containing anthero- zoids, some of which were still enclosed within the wall of the mother-cell, whilst others were free. The antherozoids of Fegatella are much larger than in the remaining Marchantiales which have been examined, and approach in this respect those of Pellia ; the spirally coiled body consists usually of two complete turns, the anterior end bearing two long cilia, whilst in most cases the thicker posterior end carries a small vesicle, doubtless representing the remains of the mother-cell. The writer has found that the discharges only take place on warm, sunny days, and are especially frequent when the plants are exposed to direct sunlight; they were not observed on dull days, nor when the plants were shaded. On bringing plants out of shade into sunlight the discharges began almost immediately, continued in rapid succession for several minutes, then became less frequent, and finally ceased. This phenomenon occurs in Fegatella plants growing in their natural surroundings, the writer having, after careful watching, several times observed it on the spot. It does not appear to have been hitherto described by writers on the Bryophyta. In some Fungi, e.g. Pilobolus 1 , As cobolus, the spores are violently ejected by means of water-pressure giving rise to jets of spray. Fegatella is strictly dioecious, and very often the male and female plants are widely separated from each other, since they do not usually occur mingled together, but form large patches, each consisting of either male or female plants. It is not at all uncommon to find a patch of female plants in fruit, although removed several feet from the nearest male plants, and it is reasonable to suppose that the fertilization of the archegonia may possibly have been effected in consequence of the antherozoids being ejected explosively from the 1 Cf. Scott, Structural Botany, pt. ii, p. 230. 272 Notes . male plants and carried to the female plants by air-currents, each antherozoid being surrounded by a thin film of water. Goebel 1 has suggested that the fertilization of the archegonia in the dioecious Marchantiales, which so often form isolated patches, might be effected by means of rain-drops falling upon the male receptacles and then splashing over the female plants. In the case of Mosses, in which similar conditions prevail, it was suggested by Kienitz- Gerloff 2 , and later confirmed by the observations of Gayet 3 , that small animals, especially insects, creeping over the patches of male and female plants may, especially in dry seasons, be instrumental in bringing antherozoids into contact with the archegonia. The examination of sections through antheridial receptacles of different ages shows that the development of the antheridia is accom- panied by that of air-spaces, which arise in the same manner as the chambers of the thallus, and whose sides are formed of cells con- taining abundant chloroplasts. Each antheridium becomes during its development sunk in a deep cavity, formed in essentially the same way as the air-spaces. As the antheridium grows in size, its cavity becomes flask-shaped, having a long neck opening above on the surface of the receptacle by a small pore which occupies the summit of one of the conical prominences already mentioned. Owing to the lateral pressure exerted by the growing antheridia, the air-spaces between the antheridial cavities become compressed and finally obliterated below, but in the upper portion of the receptacle they remain as wide chambers, each opening above by a pore of the * compound ' or ‘ barrel-shaped ’ type, the cells surrounding it being arranged in four or five superposed rings. The cells lining the chamber project inwards, and are often long, pointed, and colourless : exactly similar pointed cells are found in the air-chambers of the thallus, but they do not appear to have been previously described in the case of the male receptacle. As shown by the experiments of Kamerling 4 , it is from these colourless cells that water-vapour is given off into the air-chambers of the thallus, and very probably they have the same function here. In vertical sections the mature receptacle is seen to be divided into three well-marked zones :■ — (1) 1 Organographie der Pflanzen, p. 310. 2 Botanische Zeitung, 44. Jahrg. (1886), p. 250. 3 Ann. des Sci. Nat., ser. 8, t. 3 (1897), p. 241. 4 Zur Biologie u. Physiologie d. Marchantiaceen, Flora, 1897, p. 50 of reprint. Notes . 273 an upper zone of chlorophyll-bearing tissue, containing numerous air-spaces and traversed by the passages leading down to the antheri- dial cavities; (2) a middle zone of compact tissue, in which are embedded the antheridia, and which consists of large colourless cells, including scattered mucilage-sacs ; (3) a lower zone continuous with Fig. 17. — I. Longitudinal section through anterior end of thallus, with a male receptacle ; x 20. The antheridial cavities are deeply shaded ; Sc., ventral scales. II. Part of the same section, x 200, showing on the left the upper portion of an antheridium and its cavity, on the right an air-chamber, opening by a ‘ barrel- shaped’ pore. III. Surface-view of part of receptacle, showing two pores; the upper opens into an antheridial cavity, the lower into an air-chamber. the midrib of the thallus and consisting of compact tissue, traversed by strings of mucilage-cells, and bearing the rhizoids and ventral scales beneath. From these structural features it is clear that the male receptacle T Notes . 274 has a well-developed assimilating tissue system, together with abundant mucilage-containing cells. Now, under circumstances which favour assimilation, e.g. strong light, sufficient warmth, and a dry atmosphere, an active transpiration-current will be set up, water-vapour being given off in the air-spaces through the pointed inward-projecting cells. To make good this loss, water will pass to the receptacle through the rhizoids. A large part of the water is absorbed by the mucilage-cells, and if any of the antheridia are ripe, the walls of the antheridium itself, as well as those of the antherozoid mother-cells, being at this time largely mucilaginous, also take up water and become swdllen. The antheridia being closely packed together considerable pressure is thus set up, resulting in the expulsion of the antherozoids. F. CAVERS. Yorkshire College, Leeds. ALGOLOGICAL NOTES.— IV. REMARKS ON THE PERIODICAL DEVELOPMENT OF THE ALGAE IN THE ARTIFICIAL WATERS AT KEW. Whilst working out the algal flora of the Royal Botanic Gardens at Ivew for publication by the authorities, I have made several observa- tions on the periodicity of the flora, which I wish to remark upon more fully here. The flora 1 was found to be built up of a hot-house element, consisting for the greater part of Cyanophyceae ; of the Thames element, due to the universal use of river-water throughout the gardens ; and, lastly of the open-air terrestrial element. The blue-green Algae, which abound in every moist hot-house, have received much attention from continental algologists, with the result that they are fairly well known. How far some of the forms may be looked upon as truly exotic and as introduced together with the higher plants, cultivated in the houses, it is difficult to say 2 . It should be observed that some of these blue-green forms (e. g. Symphyosiphon 1 The constitution of the flora will be more fully discussed in the introduction to the algal flora of Kew Gardens. (See The Fauna and Flora of the Roya 1 Botanic Gardens, Kew, which is to be published in the course of this year.) 2 A large number of the blue-green Algae, which occur in the moist heat of greenhouses, have also been observed in hot springs of different parts of Europe, notably those of Carlsbad ; this seems to show that they are now truly indigenous in Europe, but can only exist under the peculiar conditions (i. e. high temperature and moisture) found at these particular spots. Notes . 275 Hofmanni, Kiitz., Symploca thermal is, Kiitz., Gloeocapsa caldariorum , Rabh., &c.) may have been originally introduced into our parts with greenhouse plants ; since reliable observations on the Algae occurring in any given district do not date back very far, whereas the cultiva- tion of exotic plants in hot-houses is an old practice. Many of the blue-green . Algae (e. g. Scytonema cinereum , Menegh., Symphyosiphon Hofmanni , Kiitz., &c.) are so absolutely characteristic for every moist hot-house, that it seems plausible that in our parts they first originated here, and only later on escaped to other (more natural) localities. I have also observed these characteristic species in many of the hot-houses of the gardens at Glasnevin, near Dublin. The hot-house flora is practically equally developed during the whole year, the conditions under which it exists remaining uniform. The flora outside, however, shows quite a different character in the winter and in the summer, and attains its maximum development in August and September; in the winter only the hardy genera of Algae ( Vancheria, Oedogonium, Cladophora , Rhizocloniuni) are present, whilst the smaller forms (Protococcoideae, &c.) are absent. Desmids, not very common even in the summer \ are quite absent, as also most of the other Conjugates, Spirogyra crassa , Kiitz., being the only species that can be met with all the year round. This species usually has a very well-developed sheath, often as much as one-fifth of the diameter of the cell in thickness 2 , and the hardiness of the species is probably due to its presence. Desmidieae first appear in March, and species of Scenedesmus and Pediastrum at the beginning of April or a little before 3 . Even in the tanks in the warmer houses (e. g. 1 Very few Desmids were also observed in the Plankton of the Thames ; analysis of the river-water shows that a considerable percentage of calcium carbonate is present (cp. Algological Notes, III : Preliminary Report on the Phyto- plankton of the Thames ; Annals of Botany, vol. xvi, 1902, p. 581). I should like at this spot to mention that since the publication of my note I have received from Professor G. S. West a paper by his father and himself (A Contribution to the Fresh-water Algae of the North of Ireland, Trans. Royal Irish Acad., vol. xxxii, sect. B, pt. i, August, 1902) which contains an account of the Plankton Algae of Lough Neagh during the months May, 1900, and August, 1901. In the same paper reference is made to a publication of Borge’s : ‘ Siisswasser-Plankton aus der Insel Mull,’ in Algologiska Notiser, 4; Botaniska Notiser, 1897. 2 A somewhat similar sheath is described for Sp. lubrica by Braun ; cp. Verjiin- gung, 1851, p. 261. 3 Most of these unicellular or few-celled forms probably only occur when the conditions of temperatures, and especially of illumination, begin to be favourable (cp. Zacharias, Uber die Ursache der Verschiedenheit des Winterplanktons in T Q, 276 Notes . Water-lily House, Victoria Regia House) this periodicity is observable. Desmids and other Conjugates are very rare before April, although some of the unicellular Protococcoideae are here to be found all the year round. Much has already been written about the periodicity in the develop- ment of certain Plankton organisms, but little attention in this respect has been paid to those inhabiting the deeper strata of the water. In all the artificial waters at Kew a regular sequence of forms was observed; it was most pronounced in the aquatics’ tank near the Jpdrell Laboratory, in which, by the removal every now and then of the mass of Algae that collects there, room is constantly being furnished for the development of other forms. Table I (see next page) illustrates this periodicity in the algal flora very well. A careful perusal of this Table will show that the flora in any one month differs more or less considerably in character from that of the preceding or succeeding month. Undoubtedly the removal of the large masses of Algae, which collect in the space of every fortnight during the summer, considerably furthers this periodical development. Thus a little time after the tank had been thoroughly cleaned out, I met with the curious red oospores of Sphaeroplea annulina , a species which had been found in abundance in this tank in a former year, but had since not been observed. These oospores had probably been liberated during the cleaning-out of the tank, and in a few weeks gave rise to a large number of vegetative filaments of the Sphaeroplea. However, even in the lake, where no such artificial agency comes into consideration, the periodicity of the flora is well marked, as will be seen by Table II (see next page). Enteromorpha intestinalis, Tetraspora gelatinosa , and Oscillaria nigra , all very abundant in the summer months, especially the first and last species, are entirely absent in the early part of the year ; they thus give the algal flora of the summer an entirely different stamp to that of the winter. In addition to this we may note the development of the Desmidieae, which is, however, relatively poor in the calcareous waters of Kew, as already mentioned. Oscillaria nigra also played an important part in the water- lily pond. In the earlier part of the year a Cladophora was the most abundant form here, and no trace of the Oscillaria grossen u. kleinen Seen, Zoolog. Anzeiger, Bd. xxii, Nos. 577 and 578, 1899, p. 19, &c.). Notes . 277 I. Table illustrating the periodical development of Algae in the tank near the Jodrell Laboratory 1 , Jan. Feb. Mar. Apr. May. June. July. Aug. Sept. Characium Sieboldi , Braun . . — — — + -f Chlamydomonas pulvisculus , Ehrb. . . — — — : + -f- + + + + Chaetophora endiviaefolia , Ag. . . . — + . +? — — — — — • Draparnaldia plumosa (Vauch.), Ag. . — — — + ' + + + — Mesocarpus pleurocarpus , De Bary . . — ■ — + + — — — Spirogyra crassa, Kiitz + + + + + + + T. + „ condensata, Kiitz — — - — — — + + i — — ,, longata, Kiitz — — — — — + + + J — Closterium acerosum (Schrank), Ehrb. . — — — ■ — ' + + + + + Sphaeroplea annulina , Ag — — — + — — Cladophora fracta , Kiitz — — — — — + + + + Ulothrix radicans , Kiitz. . . . . . — ■ — — — • + — — — Sciadium arbuscula, Braun .... — ’iJJ 1 — — — — — • — + Tetraspora lubrica , Ag — — — — — ■ lip + + — II. Table illustrating the periodical development of Algae in the Lake at Kew 1 . Jan. Feb. Mar. Apr. May . June. July. Aug. Sept. Vaucheria geminata (Vauch.), D.C., var. b. racemosa , Walz + Mesocarpus pleurocarpus , De Bary . . — — — + + | + + + + Sirogoniufn sticticum , Kiitz + + + + — — — . — — • Spirogyra porticalis , Cleve, var. a. qui- nina , Corda _ _ _ + + + Gonatozygon Brebissonii , De Bary . . — — — . — — — + — — Closterium Jenneri , Ralfs — — — — — + + + — „ Dianae , Ehrb — ■ — — 1 + + + + + Euastrum venustum , Breb — — — + + + + + Cosmarium crenatum , Ralfs — — + + + + + + „ quinarium , Lund. . . . — — — — a + + — ,, isthmochondrium , Nords , — — — — * + + + + — Staurastrum striolatum, Pritch. . . . — — — — — — — + + ,, polymorphum , Breb. . . — — — — — — + + + Cladophora crispata — — + + + + + + + Aphanochaete repens , Braun .... + + + + + + + + + Enteromorpha intestinalis , Link. . . — — — — — ■ + + + + Eudorina elegans, Ehrb -T~ — — + + + + + + Pandorina mo rum , Ehrb — ' — — + + + + + + Gonium perforate. Mull — — — + + + + + + Pediastrum Boryanum , Turp. . . . — — — + + + + + + ,, pertusum , Kiitz — — ■ — + + + + + + Tetraspora gelatinosa, Desv 1 — — ; + + + — — Loelastrum microporum (Naeg.), Braun — — — — — + + + + Tetrapedia setigera , Archer .... — — . — — — + Oscillaria nigra , Vauch — — — — • — + + + + 1 +- indicates the presence ; — the absence of any form. 2j8 Notes . was to be found. During the summer months the latter genus, however, attained an enormous development, the whole bottom of the pond being covered with a thin blue-green film from which dense, almost black masses of various shapes stood up vertically in the water. In the introductory remarks to the many algal lists that have been published I have as yet found little discussion on the periodicity of Algae. Hilse 1 in 1863 remarks of the Algae in the numerous small pools in the granite quarries of the Galgenberg near Strehlen : ‘ Sehr bequem ist auch hier der Wechsel der einzelnen Arten zu beobachten. So findet man in den Jahreszeiten Fruhling, Sommer und Herbst in ein und derselben Wassersammlung sehr oft auch verschiedene Algen, ja manche dieser Species hat kaum eine Dauer von einigen Wochen (!)/ Bohlin 2 quite recently, in a very com- prehensive account of the algal flora of the Azores, remarks : ‘ II est sur qu’une certaine quantity de ces plantes sont, plus qu’on ne le pense en general, liees a certaines saisons.’ This remark applies to a tropical flora, but might equally well be applied to the develop- ment of an algal flora in our parts. The few remarks made by Schimper 3 on the periodicity of the water-plants all refer to the Phanerogams or to the Plankton. The writer is at present occupied with the collection of data concerning the periodical development of Algae in different parts of the South of England, and hopes at a future date to enter much more fully into this interesting subject. F. E. FRITSCH. Jodrell Laboratory, Kew, October 30, 1902. NOTE ON ABNORMAL PLURALITY OF SPORANGIA IN LYCOPODIUM RIGIDUM, Gmel.— Though few, if any, morpho- logical generalizations are without any exceptions, one which has hitherto stood, I believe, without any recorded instances to the contrary is that in the Lycopodinae (excl. Psilotacea) the sporophyll 1 Hike, Netie Beitrage zur Algen- 11. Diatomeen-Kunde Schlesiens, insbesondere Strehlens, Abhandl. d. Schles. Ges. f. vaterl. Cultur, naturw.-medicin. Abtheilung, 1863, Heft II, p. 57. 2 Bohlin, Etude sur la flore algologique d’eau douce des Agores. Bihang till K. Svenska Vet.-Akad. Handlingar, Bd. 27, Afd. Ill, No. 4, 1901, p. 5. 3 Schimper, Pfianzengeographie, p. 857. Notes. 279 subtends only a single sporangium. An exception has come at last, on a specimen of Lycopodium rigidum, Gmel., in the Glasgow University Herbarium; the sheet is labelled, Columbia, Hartweg, No. 1463. The specimen shows no special peculiarities beyond that to be described; the other sporophylls and sporangia are ot the normal type, even those in the immediate neighbourhood of the abnormality. Fig. 18. A single sporophyll, however, of slightly greater width than the average, subtends not one but two sporangia of slightly unequal size placed side by side (Fig. 18) : they are individually smaller than the average sporangia in th§ near neighbourhood on the same axis. The interest of this fact lies in its rarity : there is perhaps no character which marks off the plants of Lycopodinous affinity from others so clearly as the constancy of the solitary sporangium. Inter- polation of accessory sporangia, which is in some groups, such as the Ferns, so frequent a source of increase in their number, is entirely absent in the Lycopods. In the Psilotaceae it is true that numerical constancy is not observed, and irregularity of number of sporangia is not infrequent both in Psilotum and Tmesipieris. But in these 28 o Notes. genera a plurality of sporangia is the normal condition, and the closeness of relation of these organisms to the true Lycopods is open to question. The importance of a morphological character for comparative purposes depends on its constancy ; and on this ground the solitary, leaf-subtended sporangium of Lycopodium may be held as a character of high morphological value ; it stamps this series of Pteridophytes as peculiar from all others. But it is not necessary that the simple type should always be strictly maintained; few characters in the whole series of plants are more stereotyped than the structure of the Bryophyte sporogonium ; yet branched, two-headed sporogonia are occasionally found. The causes of this are obscure ; probably nutritive conditions have close con- nexion with it. It is with such cases of plural development of parts normally single that I should rank this plurality of sporangia in lycopodium rigidum . On the other hand, it has lately been shown by Solms-Laubach (Bot. Zeit., 1902) that Isoetes, which has usually a simple axis, is occasionally branched ; in this we may see a fresh indication of its Lycopodinous affinity, where dichotomy is common. The case is somewhat the same in Phylloglossum, where also, though the plant is normally unbranched, occasional dichotomies occur. These branchings seem rather reminiscent of a feature common in the main groups to which these plants belong, than to be actually new developments. But the case of the plural sporangia in Lycopodium rigidum I should regard as a new development; it probably arose by a separation of the sporogenous group of a normal sporangium into two : on this point, however, it is impossible to go beyond mere conjecture, since the case is isolated and observed only in the mature condition. I do not think it will be wise to attach high importance to this abnormality for purposes of comparative argument, beyond recog- nizing that it shows how even the most rigid facts of morphological experience are liable to exception, and that this applies equally to spore-bearing members, in cases where their forms seem most stereotyped. Glasgow, October , 1902. F. O. BOWER. OWING to the amount of material in hand, the Editors have found it desirable to hasten the publi- cation of the present number of the Annals of Botany , which therefore appears in March, instead of in April, as announced. It is proposed to issue the next number as soon as it is ready. The Early Stages of Spindle-Formation in the Pollen-Mother-Cells of Larix. BY CHARLES E. ALLEN, Instructor in Botany in the University of Wisconsin. With Plates XIV and XV. Introduction. N UCLEAR division in the pollen-mother-cell of Larix davurica , Trautv., was described and figured by Belajefif (’94). He finds, in the early prophases of the first mitosis, a system of radial fibres extending from the nuclear membrane to the cell periphery. Later, a close felt-like layer of fibres, or meshes, appears just without the nucleus ; some fibres are still left in the peripheral cytoplasm. This arrangement, he suggests, may have resulted from a drawing together of the radial fibres about the nucleus ; but he finds none of the intervening stages. The fibrous material already present within the nucleus increases in amount, forming a dense net- work ; the nuclear membrane disappears, and with it the distinction between intra- and extra-nuclear fibres. The peripheral fibres group themselves so as to converge toward points (one to four in a section) near the cell-wall, and the fibres of the central mass become so arranged with reference to these points as to form a multipolar spindle. Bundles of fibres connect the chromosomes, lying in the central region of [Annals of Botany, Vol. XVII. No. LXVI. March, 1903.] U 282 Allen. — The Early Stages of Spindle- Formation the spindle, with the poles. The number of poles is reduced to two, possibly by fusion, resulting in a typical bipolar spindle. Belajeff’s observations of Lilium and Fritillaria pollen-mother-cells agree, so far as they go, with those of Larix. A dense intra-nuclear network is formed ; then knots, possibly, he thinks, centrospheres, appear at various places in the cytoplasm, from which fibre-bundles penetrate the nuclear membrane and attach themselves to the chromosomes. The membrane disappears and a multipolar figure is formed, which passes into a bipolar spindle. Strasburger’s (’95) description of some stages of the same division in the pollen -mother-cell of Larix europaea corro- borates that of Belajeff as to the felted stage, the disappear- ance of the nuclear membrane, the formation of a central fibrous system, a multipolar and finally a bipolar spindle. Nemec (’98 £) describes quite differently spindle-formation in Z. decidua (Z. europaea , DC.). He finds an early stage of cytoplasmic radiation, succeeded by an aggregation, just with- out the nucleus, of granular material, sharply separated from the much-vacuolated outer cytoplasm. Next to the mem- brane appears a hyaline region, which grows at the expense of the granular zone. In the hyaline layer appears a reticulum ; this develops into a system of fibres, which orient themselves into a multipolar figure. Fibres also appear within the nucleus, the membrane disappears, and from the whole fibre-complex a bipolar spindle is developed. Belajeff was the first to interpret a multipolar as a stage in the development of a bipolar spindle ; but Strasburger (’80) had, some years earlier, figured a tripolar spindle in the endosperm of Reseda , and had described similar figures in Ornithogalum and Leticojum. Later, he (’88) figured the spindle in Leucojum ; also a multipolar spindle in the equatorial plate stage from the endosperm of Allium , whose great number of chromosomes led him to explain it as due to a fusion of several nuclei. A felted stage, similar to that described by Belajeff, had been found by Strasburger (’88) in Leucojum . in the Pollen-Mother-Cells of Larix. 283 In recent years, a multipolar origin of the spindle has been found in many Spermatophytes. Such a stage is described in the pollen-mother-cell of Lilium by Farmer (’93, ’95 d), by Strasburger (’95), Miss Sargant (’97), and Mottier (’97). Farmer’s preliminary note (’93), indeed, preceded the publica- tion of Belajefif’s paper, just cited, but the substance of the latter’s discoveries had been stated in two earlier Russian notes. Mottier finds, succeeding a radial stage, a felted layer just without the nucleus, from which fibres extend toward the cell-wall so as to form a number of poles. But as the nuclear membrane disappears and the fibres penetrate the nuclear cavity, the multipolar condition often disappears, to recur when the cavity is completely filled by the fibrous mass. In the pollen- mother-cells of Podophyllum and Helleborus the process is similar, except that there is no multipolar arrange- ment until after the membrane disappears. A multipolar stage occurs, too, according to Mottier, in the second mitosis in the pollen-mother-cell of Lilium ; also (’98) in the divisions in the embryo-sac of Lilium and Helleborus. Multipolar figures which develop into bipolar spindles are described in the pollen-mother-cells of Hemerocallis , by Juel (’97); in those of Nymphaea , Nuphar , Limodorum and Magnolia , by Guignard (’97#, '97b, ’98) ; of Cobaea and Gladiolus , by Lawson (’98, ’00) ; of Bignonia , Symplocarpus and Peltandra , by Duggar (’99, ’00) ; of Convallaria and Potamogeton , by Wiegand (’99) ; of Arisaema , by Atkinson (’99) ; of Passiflora , by Miss Williams (’99j; of Lavatera , by Miss Byxbee (’00); of Magnolia and Liriodendron , by Andrews (’01) ; and in those of Galtonia and Convallaria , by Schniewind-Thies (’01). Schniewind-Thies finds similar figures in the embryo-sacs of Galtonia , Convallaria , Scilla and Ttdipa ; and Duggar (’99) describes them in the embryo-sac of Bignonia. Of the cases above mentioned, a felted stage preceding the multipolar is described in Hemerocallis, Nymphaea , Nuphar , Limodorum , Magnolia (Guignard and Andrews), Gladiolus , Peltandra , Convallaria (Wiegand), Potamogeton , Lavatera and Lirioden- dron ; and an earlier radial stage is found in Cobaea , Peltandra, 284 Allen . — The Early Slaves of Spindle- Formation Passiflora and Lavatera , and in the second division in Magnolia and Liriodendron (Andrews). In a type of spindle-formation first described by Rosen (’95) in the root-tip of Hyacinthus , a thin hyaline extra- nuclear zone is seen, whose material becomes aggregated on two opposite sides of the nucleus. Within each cap so formed, fibres appear and grow in length, attaching them- selves at one end to the nuclear membrane and finally converging at the other end to a common point. Then the membrane disappears and the spindle is completed. Nemec (’97, ’98#, ’98$, ’99#, ’99 £,’99 c) describes spindle-formation from similar extra-nuclear caps in root-tips and other vegetative tissues of Allium , Hemerocallis , Solanum , and a long list of plants. He finds that in general the spindles in vegetative cells are from the start bipolar, while those in reproductive cells are originally multipolar. Hof (’98) finds similar polar caps in the root-tips of Ephedra and Vicia. In the former case, the spindle is originally bipolar, in the latter monaxially multipolar, becoming bipolar. Schaffner (’98, ’ 01 ) describes spindles arising from similar extra-nuclear caps in the root- tips of Allium and Erythronium ; and Fullmer (’98, ’99) finds the same thing in pine seedlings, and also in pollen-mother- cells of Hemerocallis , where, however, he describes also an early radial stage. Miss McComb (’00) relates a similar history in the root-tips of Allium , Vicia and Erythronium , except that instead of the early hyaline layer she finds a kinoplasmic weft or felt surrounding the nucleus ; and it is this felt that becomes aggregated into the polar caps. Strasburger (’ 00 , p. 118 ) has pointed out that in the vege- tative divisions described by N£mec the spindle primordium (‘ Anlage ’) at each end of the nucleus is at first composed of separate spindle-bundles, not converging to a common point. He proposes for this condition the term ‘ multipolar diarch,’ as distinguished from the ‘ multipolar polyarch ’ form common to reproductive cells, in which poles arise on all sides of the nucleus. He finds, in the root-tips of Ephedra and Vicia , a finely fibrous extra-nuclear layer which becomes aggregated in the Pollen- Mother- Cells of Larix . 285 into polar caps, and from these caps fibres grow out into a liquid which appears between the fibrous cap and the nuclear membrane. But there is no sharp line of distinction between the two methods of spindle-formation ; for in the pollen-mother-cell of Iris the origin of the first spindle is multipolar polyarch, that of the second multipolar diarch ; while in the pollen-mother-cell of Nymphaea the origin of the first spindle is similar to that of the second in Iris . Duggar (’00) finds, too, that in the division of the microspore nucleus of Symplocarpus and Peltandra the spindle is originally multipolar diarch, the fibres being arranged perpendicularly to the wall near which the nucleus lies. Mottier (’98) describes, in the vegetative cells of Lilium , a multipolar stage preceded by an extra-nuclear felt, just as in pollen-mother-cells ; and a multipolar spindle is figured by Ikeno (’98) in the embryo of Cycas. Multipolar spindle-figures have an important bearing on the question as to the presence or absence of central bodies (attraction-spheres, centrospheres, centrosomes, &c.). We have seen that the evidence is conclusive for the general existence of a multipolar stage in the history of the spindle in the cells of the flowering plants ; and such a stage seems to negative the possibility of the formation of the spindle in these plants through the agency of centrosomes which station themselves at opposite points in the cell, so initiating mitosis and determining the position of the spindle-poles. But Guignard, who (’91 a , ’91 b, *91 c) first described attraction- spheres in Phanerogams, has more recently (’97 a, ’97 b , ’98) maintained that the poles of the multipolar figure are often occupied by centrosome-like granules, which are, he holds, true kinetic centres, and that the bipolar stage results from their fusion into two typical centrospheres. A very similar process has been described by Moore (’94) in certain animal cells. But even Guignard admits that the spheres may dis- appear in the resting stage and be formed de novo during mitosis, sometimes not until after the appearance of the multipolar spindle ; in the latter case, the cones arise by the 286 Allen . — The Early Stages of Spindle- Formation activity of the kinoplasm in the absence of undifferentiated dynamic centres. In spite of numerous accounts of central bodies, the great weight of evidence now seems to be against their existence in the Seed Plants, if we except the still disputed case of the ‘ blepharoplast.’ A full resume of the centrosome discussion has lately been published by Strasburger (’00), who has still more recently (’01) applied to the pollen- mother-cells of Asclepias and Cynanchum , with negative results, all the methods used for the demonstration of the central bodies in animal tissues. The observations and ex- periments of Hottes (reported by Strasburger, ’00) and of Nemec (’99 d, ’ 01 ) indicate that kinoplasmic or nucleolar granules or masses may often appear at or near the spindle- poles, and that their occurrence is favoured by certain stimuli, as, for instance, subjection to low temperatures. Demoor (’ 95 ) also finds that ‘ centrosomes ’ are made visible by cooling. The only history of a multipolar spindle so far completely worked out among the Pteridophytes is that of the spore- mother-cell of Equisetum , described by Osterhout (’ 97 ). He finds, just without the nucleus, a blue-staining cytoplasmic layer, which becomes fibrous ; the fibres are at first parallel to the nuclear membrane, but later take on a radial arrange- ment, many of them extending to the plasma-membrane ; then they group themselves into a multipolar figure. The nuclear membrane disappears, and the extra- and intra- nuclear fibres form a continuous system, whose poles fuse in two groups, forming a sharply bipolar spindle. No centro- somes are present at any stage. The multipolar origin of this spindle is corroborated by Nemec (’98 #) ; but Campbell (’ 95 , p. 427) finds directive spheres present in the divisions of the spore-mother-cell, and describes no multipolar stage. Smith (’00 a) notes that the spindle in the microspore-mother- cell of Isoetes appears to have a polycentric origin. In the spore-mother-cells of Osmunda , he (’00 b) describes the for- mation of a spindle from two extra-nuclear polar caps — a ‘ multipolar diarch ’ origin. Occasional tripolar figures he 287 in the Pollen-Mot her- Ceils of Larix . considers abnormal. Spindle-formation from polar caps is found in the meristem of Psilotum by Rosen (’95), in vege- tative tissues of Equisetum , Aspidium and Alsophila by Nemec (’98 a, ’98 b, ’99 a), and in vegetative cells of Aspidium by Hof (’98). Central bodies have been described in the Pterido- phytes by numerous observers.; but the evidence for and against their existence here is practically the same as in the case of the Seed Plants, and here as in the higher group the preponderance seems to be on the negative side of the argument, A peculiar form of quadripolar spindle, suggestive of the multipolar figures already described, is found by Farmer (’94, ’95 a, ’95 b, 95 c), in certain Hepaticae whose spores are formed by the division of the mother-cell into four lobes. In Pallavicinia he finds that four daughter-nuclei are formed simultaneously, one at each of the poles ; but in other cases the original poles approximate in pairs to form either a sharply bipolar spindle or one with forked ends, and the division results in two daughter-nuclei, each of which again divides. Davis (’01) finds a quadripolar figure in Pellia , but he interprets it as a stage in spindle development in which a fibrous extra- nuclear weft takes this peculiar shape in consequence of the lobing of the cell. He (’99) also finds a felted stage in the developing spindle in the spore-mother-cell of Anthoceros , followed apparently by a multipolar, then by a bipolar stage. Centrospheres and centrosomes have been described in a number of liverworts. The only case of spindle-formation reported among the Thallophytes which seems to conform to the multipolar type is in the vegetative cells of Chara, described by Debski (’98). The bipolar spindle develops, through stages which he, did not follow, from a central fibrous system ; the latter is partly of nuclear and partly of cytoplasmic origin. This isolated case emphasizes the width of the gulf that seems to separate the Characeae from other Thallophytes. Central bodies which take part in spindle-formation, which divide, and, in some cases at least, persist through the resting stage, have 288 Allen. — The Early Stages of Spindle-Formation been found in species representing diverse groups, and it is generally recognized that a method of spindle-formation accompanied by the activity of a centrosome is at least of widespread occurrence among the lower plants. As we have seen, there is much uncertainty and variance in the accounts of different authors as to what takes place in the early history of the spindle in the higher plants, previous to the appearance of the extra-nuclear felt. Besides, the presence of centrosomes, though rendered extremely im- probable, is not admitted by all writers, at least, to be entirely excluded by known facts as to the multipolar origin of the spindles. For these reasons, special attention has been paid in the present investigation to the early prophases of mitosis, and an attempt has been made to follow closely the history of the cytoplasmic structures in these stages. The problem here involved is a purely physiological one, and the description of structures occurring in isolated stages of karyokinesis is by no means sufficient for its solution. A complete series of stages, showing the changes actually going on within the cell, must be studied, and their connexion shown. From this point of view, much of the discussion regarding the presence or absence of f centrosome-like granules’ at the spindle-poles is seen to be useless. There can be no doubt, from the citations already given, that granules or larger masses are often to be found at the poles ; but nothing can be determined as to the significance of these bodies until the complete history of the spindle has been traced. Original Observations. The following description applies to the first nuclear division in the pollen-mother-cells of Larix europaea , DC. Male cones were fixed at various times during the fall, winter and spring, both from material just taken from the trees and from that whose development was hastened by keeping it for from one to four days in a warm room. Strasburger (’00, p. 68) finds that material forced in this way yields the same karyo- kinetic figures as that which has developed more slowly in the Pollen- Mother -Cells of Larix. 289 out-of-doors. Of several fixations tried, the best results were obtained with Flemming’s stronger solution. The sections, five microns in thickness, were stained with the triple stain. I have also had the privilege of examining some similarly- fixed and stained preparations made by Professor R. A. Harper and by Mr. H. G. Timberlake. Several of my drawings are from Professor Harper’s preparations, and one is from one of Mr. Timberlake’s. Living pollen-mother-cells have also been examined and compared with killed material. The process of spindle-formation may be considered as divided into five periods or stages ; the division is somewhat arbitrary, and consecutive stages are in no case sharply separated from one another. 1. The Pre-Radial Stages. The earliest material that I have studied was gathered and fixed October 24. The pollen-mother-cells are still packed closely together, but are beginning to round up and separate from each other. Each cell seems to be bounded only by a distinct blue-staining plasma-membrane ; at least, I have been unable to distinguish, by the use of the orange stain, any layer of cell-wall material. Between the separating cells is a blue-staining material, possibly the old disorganizing cell- wall, sometimes appearing as a distinct layer of some thickness, sometimes as a cloudy mass. Fig. i, PI. XIV, shows a pollen- mother-cell in this stage. Groups of red-staining bodies, the chromatin tetrads, are seen in the nucleus, just within, or often in contact with, the nuclear membrane ; segmentation of the spirem thread, therefore, has already occurred. There is usually a single nucleole (sometimes two), * in general of a rounded and somewhat irregular shape. Much of the irregularity of outline, however, is due to adhering clumps of a usually less dense and blue-staining substance — the linin. Linin is also found in contact with the chromosomes, and, in the form of ragged, wavy, granular fibres, connecting the chromatin groups with each other, with the nucleole, or running from nucleole or chromosomes to the nuclear membrane. 290 Allen . — The Early Stages of Spindle- Formation Often the nucleole becomes by this means the centre of a system of radiating fibres, as is shown at a later stage in Fig. 2. The only visible structure in the cytoplasm in the earliest stage is a fibrous network. The apparently empty meshes are of varying shapes and sizes ; in general they are smallest near the nucleus and increase in size toward the periphery of the cell. Scattered about upon the fibres and between them are granules, staining blue like the fibres. These granules are probably, in large part at least, cross-sections of fibres, and they are no more numerous than such sections would be likely to be in such a network. Often they are shown by focusing to extend through the thickness of the section. Fig. 2 is from material gathered and fixed March 15 ; the fixation is according to Vom Rath’s picric-acetic-osmic acid and platinum chloride formula. There has evidently been no great change during the winter. The Vom Rath fixation, however, does not permit of so good a differential stain as the Flemming, and the preparations are in general not as satis- factory. The fibrous network is still present, though not well brought out ; between the meshes, especially near the nucleus, is a granular or cloudy substance, but the large peripheral meshes are still empty, giving the outer part of the cell a vacuolated appearance. In the cytoplasm are seen occasional small rounded bodies of distinct outline, staining homo- geneously and a little more deeply than the rest of the cytoplasm. Fig. 3 shows a somewhat later condition (in Flemming fixation, as are all the remaining figures). The cells have now rounded up and are provided with a relatively thick cell-wall. The blue intercellular substance has disappeared, and the cells float in a colourless liquid. The cytoplasm now plainly contains two constituents, the fibrous meshwork first observed, which stains blue, and a cloudy or very finely granular, orange-staining material. The latter substance does not occupy all of the inter-fibrous spaces, but clear areas of varying size are also scattered through the cytoplasm. Some- 291 in the Pollen-Mother-Cells of Larix . times the clear spaces are larger and more numerous in the peripheral region, but often, as in the cell shown in Fig. 3, the cytoplasm presents in this respect a very uniform appearance. The granules, or sections of fibres, are present as before, and also the larger rounded cytoplasmic bodies, which stain less densely blue than the fibres. Often a cyto- plasmic fibre can be clearly traced as it passes through the nuclear membrane and is attached to one of the chromatin groups. For this purpose sections are specially favourable which cut the nucleus tangentially ; in such a section a fibre running diagonally to the cutting-plane can be followed, by a change of focus, through the membrane, which is transparent and is here visible only as a bluish cloud. A portion of such a section is shown in Fig. 4. Comparison of living cells at this period is helpful. The outlines of the large round or elliptical nucleus, one or two nucleoles, usually near the centre of the nucleus, and the chromosomes just within the nuclear boundary, are all plainly visible ; and some of the longer linin fibres can be made out. Little can be determined in living material regarding cyto- plasmic structures ; occasionally one of the coarser fibres can be traced for some distance. 2. The Radial Stages. Very soon the cytoplasmic fibres begin to show a definite arrangement. In a section through a single cone may often be found a series of stages from the one just described to a distinctly radial arrangement (Fig. 5). The fibres arrange themselves so that many of them extend perpendicularly from the nuclear membrane out into the cytoplasm or even to the periphery of the cell. At first, however, most of the radial fibres are relatively short and end in the cytoplasm. They are also in general not straight, but rather irregularly wavy. A vacuolated region may still be present in the peripheral cytoplasm, as appears in Fig. 5. The fibres soon increase in length, and a complete system of fairly straight radial fibres is formed, extending from the 2 Q2 Allen . — The Early Stages of Spindle- Formation nuclear membrane to the plasma-membrane. In the cell represented by Fig. 6, there is a very slight plasmolysis around much of the cell periphery ; the plasma-membrane, stained deep blue like the fibres, is separated from the orange cell-wall, and it is plain that the fibres terminate in this membrane. The cytoplasm has also shrunken away slightly from one side of the nuclear membrane, and one fibre can be traced across the gap to the membrane and into apparent continuity with an intra-nuclear fibre. The number of blue cytoplasmic granules shown in median section is now much less than in the earlier stages, as would be expected if they are sections of fibres. Often the fibres are connected with each other by branches ; this may be taken to indicate that the radial figure has resulted from a pulling out and rearrangement of the meshes of the earlier network. A study of the succession of stages tends to strengthen this view of the origin of the radial fibres. However, it seems plain that there is also an actual growth in length of the fibres after they have assumed the radial position. The possibility of a combination of the two processes — a pulling out of the meshes and a growth of the fibres— will be discussed later. 3. The Formation of the Felt. A folding-over of the fibres (Figs. 7-1 1) now occurs, so that they come to assume a position parallel to the nuclear membrane. They are also gradually drawn in toward the nucleus, until theyform a dense fibrous felt about the membrane. Not all the fibres, however, take part in the formation of this felt ; many of them remain scattered about, lying in various directions in the cytoplasm. During the folding-over process, a tendency is noted for fibres to approach each other in the neighbourhood of the cell-wall (Fig. 8), so as to form figures suggestive of those shown by Osterhout (’97, Figs. 4, 5), in Equisettim , immediately following the radial stage. Such figures, however, do not in the Larch represent the beginnings of a multipolar spindle, as Osterhout finds to be the case in Equisettim. In these stages there is sometimes a zone con- 293 in the Pollen- Mother -Cells of Larix . centric to the nuclear membrane, and about midway between that and the cell-wall, in which the fibres are bunched. This zone appears frequently in the preparations from this stage down to that of the equatorial plate, and is suggestive of the kinoplasmic zone figured by Mottier (’97, Figs. 5, 6) in the Lily. But every cell containing such a zone, so far as I have observed, shows a marked shrinking and distortion, and it seems extremely probable that the bunching of the fibres is here an effect of the fixation. Fig. 16, PI. XV, shows a cell at a much later stage, which, in connexion with considerable shrinking and some plasmolysis, shows this outer fibrous zone ; the fibres here are so arranged in several places as to form ‘ cyto-asters,’ suggesting those seen by Mottier (’97, Fig. 38) in Podophyllum , as well as the asters found by Morgan (’96) to be produced in the unfertilized or fertilized eggs of sea- urchins and ascidians by treatment with salt solutions of a certain strength, and similar asters found by Mead (’98 £) in the cytoplasm of unfertilized eggs of Chaetopterus when placed in sea- water. In the two latter cases, the cyto-asters seem to occur as a result of the action of a solution in which the eggs are immersed, the effect being similar, perhaps, to that of a poor fixing-fluid. During and after the formation of the extra-nuclear felt, there is often a concentration of the granular orange-staining element of the cytoplasm about the nucleus, giving again a vacuolated (not a spongy) appearance to the peripheral cytoplasm. The linin gradually becomes more regularly fibrous, but the fibres are still ragged and granular. The nuclear membrane is still intact, staining deep blue like the fibres. The cell shown in Fig. 9 is considerably shrunken in fixation ; plasmolysis has pulled the nuclear membrane away from the cytoplasm on one side and into the nuclear cavity, where it can be followed, by focusing, through the thickness of the section. There can be no doubt in a case like this that the nuclear membrane is something more than a film due to surface tension between the nuclear sap and the cytoplasm. It is a distinct cell-organ, which retains its 294 Allen . — The Early Stages of Spindle- Formation continuity in spite of a very considerable displacement and distortion. In favourably stained sections, as that represented in Fig. 8 , the cell-wall is orange, and the plasma-membrane blue like the fibres and the nuclear membrane. In optical section, the two membranes and the larger fibres closely resemble each other in colour, density, and thickness. The dark rounded bodies seen in the cytoplasm in Fig. 8 are stained red, like the nucleole. They are doubtless the bodies which have been so frequently described as extra-nuclear nucleoles, and are to be found in many preparations from this stage onwards. They are often, though seemingly not always, in contact with the fibres; there is also a tendency for them to appear more numerously near the periphery of the cell than toward the interior, especially if the peripheral region is much vacuolated. Their number is much greater than that of the blue bodies noticed in earlier stages, so they can hardly be derived from those. Besides, the blue bodies are still occasionally to be seen. On the other hand, the nucleole shows no perceptible diminution in size or density. Its apparent irregularity of shape in the figures is largely due to cohering chromatin masses and linin fibres. There are often to be seen in the liquid surrounding the pollen-mother-cells, and usually clustered about the latter, red-staining bodies of very varying size, exactly resembling those noted in the cytoplasm. This suggests the possibility that both classes of red bodies are drops of unassimilated food substances, perhaps of soluble proteids, which have been precipitated by the fixing-solution. The absence of the membrane on one side of the nucleus in Fig. 10 is due to the fact that the section is cut close to the surface of the nucleus, and is partly tangential to it. When the extra-nuclear felt is fully formed (Fig. 12, PI. XV), there is a tendency toward a zonal arrangement of the cyto- plasm ; outside the felt is a granular region, and between this and the plasma-membrane a zone containing many fibres and little granular material. But fibres can sometimes be seen running out from the inner felt toward the periphery, as 295 in the Pollen- Mother-Cells of Larix. figured by Belajeff and Strasburger. The nuclear membrane now has a folded or wavy outline and often a granular appear- ance. The nucleole also shows signs of dissolution ; it displays a greater affinity for the orange stain, is vacuolated (Fig. is) and often collapsed. There is about this time a marked increase in the amount of intra-nuclear fibres, which, however, are still ragged, granular, and wavy. 4. The Multipolar Spindle. After the nuclear membrane disappears (Fig. 13), a distinc- tion may be made for a time between the fibres derived from the cytoplasmic felt and those filling the nuclear cavity, which seem to be wholly or chiefly of nuclear origin. The latter, though now forming a continuous system with the cytoplasmic fibres, are relatively loosely arranged, with large spaces between them, and are still granular, while the cytoplasmic fibres still form a rather compact layer and are much more uniform in thickness. Already a tendency can be noted to a pulling out of the fibres in certain places to form poles. This seems to come about, not under the influence of peri- pheral fibres, as described by Belajeff, but by an actual outward movement of the ends of some of the fibres of the central mass. At least, the study of a large number of preparations shows no regularity as to the presence of fibres running tangentially from the central mass toward the cell periphery; such fibres are sometimes present, sometimes short or slender, and often wholly absent. I have seen no evidence that these or other peripheral fibres determine the position of the cones of the multipolar figure. The nucleole has disappeared, nearly or quite simultaneously with the disappearance of the membrane. The central fibres soon lose their granular appearance and cannot be distinguished from the outer ones ; the whole mass of fibres assumes more and more the appearance of a multipolar spindle. Commonly three or four poles, sometimes indications of one or two more, - appear in a section. The fibres begin to gather into bundles which run from the chromosomes to the poles. The cell 296 Allen . — The Early Stages of Spindle- Formation drawn at this stage (Fig. 14) is unusually rich in fibrous material, also in c extra-nuclear nucleoles.’ It is very common to find a relatively clear zone surrounding the developing spindle (Figs. 13, 15, 16); apparently on the dissolution of the nuclear membrane the kinoplasmic weft presses into the cavity, leaving a clear zone between itself and the still present layer of granular cytoplasm. 5. The Completion of the Spindle. The further history of the spindle is essentially what has been described by many of the writers already cited. The arrangement of the fibres into bundles becomes more regular ; the fibres forming the bundles are straightened out ; the number of poles decreases, apparently as a result of this straightening (Figs. 15-18), until the fibres all lie approxi- mately parallel, forming a c multipolar diarch 5 figure. By the time the chromosomes are arranged on the equatorial plate (Fig. 19), the spindle is fully formed. Its fibres con- verge, not to definite points, but into two polar regions. At first view they seem to end in these region's ; but by careful examination and focusing, the fibres, here very lightly stained, may be traced through the polar area into the cytoplasm beyond, where they spread out, still less deeply stained than in the body of the spindle, to form a system of polar radia- tions. The effect is very much as though the whole bundle of fibres seen in Fig. 18 had been constricted at two points, one not far from each end, and still allowed to spread out, fan-like, at the ends and in the equatorial region. The fibres can be followed from the polar region out into the peripheral region of the cytoplasm, but only occasionally as far as the plasma-membrane. No indication of any kind of central body has ever been seen in the polar region. Some polar radiations are seen which cannot be traced as continuations of the spindle-fibres ; such radiations are more numerous in the diaster stage (Fig. 20), and here also they diverge from a general region rather than from a distinct point, and no central body is to be found. in the Pollen- Mother- Cells of Larix . 297 Conclusions. The facts observed in the pollen-mother- cell of Larix seem conclusive as to the continuous presence in the cyto- plasm, from the very early prophases, of a distinct fibrous system, which, after a series of rearrangements and changes of position, becomes, in conjunction with another set of fibres of nuclear origin, the karyokinetic spindle. A careful study of the preparations leaves no doubt, I think, that the fibres of the reticulum first seen actually become rearranged into a radial system, that this in large part passes into a close extra-nuclear felt, and that the fibres of this felt become eventually the contribution of the cytoplasm to the com- pleted spindle. It is impossible to determine in the mature spindle that any special portion is derived from the cytoplasm or from the nucleus ; but each source clearly furnishes an important part. It follows that the active spindle-forming substance, kinoplasm, may first appear, in fibrous form, either in the nucleus or in the cytoplasm ; and we may infer that the place of origin of the spindle-fibres, whether nuclear or cytoplasmic, or, as in the present case, partly nuclear and partly cytoplasmic, depends upon the conditions obtaining in, and the relations between, the nucleus and cytoplasm of the cell concerned. The facts accord with this inference ; spindles of intra-nuclear origin sometimes occur in connexion with an unusual size of the nucleus, as in the generative cell of Zamia (Webber, ’01), or where there is a paucity of cytoplasmic kinoplasm, as in instances cited by Strasburger (’00) in young anthers and nucelli of Lilium and in the growing point of Viscum ; and a greater proportional supply of extra-nuclear kinoplasm may result in spindle-formation such as Nemec finds in many vegetative cells, where an extra-nuclear bipolar spindle is completely formed, save for a short equatorial portion, while the nuclear membrane is still intact. But in spite of the range of variation which has been found in this and in other respects, I think that we may venture to present tentatively, in a general outline, the essential steps in x 298 Allen . — The Early Stages of Spindle-Formation the formation of the spindle in the Spermatophytes, and perhaps in the Pteridophytes as well. Such an outline might be somewhat as follows : — 1. A considerable amount of kinoplasm is present in the cytoplasm, at least by the time of the early prophases, as a more or less uniformly distributed, fibrous reticulum. It will be important to trace still further back the history of the kinoplasm ; but no observations yet made seem to throw any light upon this problem. Indeed, very few observers have followed spindle-formation back even to as early a point as this ; but Miss Williams (’ 99 ) and Miss Byxbee (’00) find that the spindle primordium ( c Anlage ’) develops from an early cytoplasmic meshwork. 2. The fibres of the reticulum become so arranged as to extend radially from the nuclear membrane out into the cytoplasm. It seems quite likely that this results partly from a radial pulling out of the meshes ; but very probably there is also an actual growth in length of the fibres composing the reticulum, so that many of them finally reach to the plasma- membrane. Several authors have been cited who find a radial arrangement of fibres at this period. 3. As a result of a folding-over of the radial fibres, a felt is formed just without the nuclear membrane. 4. The nuclear membrane and the nucleole disappear, and the nuclear cavity also becomes occupied by a set of fibres. 5. The peripheral fibres of the central mass become pulled out to form several or many cones. 6 . The fibres, nuclear and cytoplasmic, are gathered into bundles, forming a multipolar figure. 7. The number of poles is reduced, by fusion, to two. The felted stage and the succeeding steps in the process have been so often noted that there can be no doubt in these later stages as to the regular course of events. Osterhout’s description of the formation of the cones in Equisetum by a grouping of radial fibres, which in turn proceed from a felted layer, suggests the interesting possibility of a constant difference in the succession of events as between Seed Plants in the Pollen-Mother-Cells of Larix. 299 and Pteridophytes ; the testing of this possibility must be left to future research. So far as I know, no study has been made in vegetative cells of the stages previous to the appearance of the felt. The difference between 4 multipolar polyarch 5 and 4 multipolar diarch ’ spindles seems, from the descriptions of Strasburger ('00) and Miss McComb (’00), to result from the fact that in the latter form the felted layer, instead of giving rise to spindle- cones on all sides of the nucleus, first becomes aggregated into polar caps, and so the cones arise in two groups. Strasburger shows that the extreme cases are connected by transitional forms ; and Nemec (’99 a, ’99 c, ’99 d) thinks that by artificial changes in the physical conditions of the cell a polyarch instead of a diarch 4 Anlage ’ may be produced. He also finds that in normal mitoses in many vegetative cells the nuclear membrane persists until after the spindle ‘ Anlage * has become sharply bipolar; and, as I have suggested, this is what we might expect if the cytoplasm furnishes a larger proportion of the spindle-forming fibres than is commonly the case in spore-mother-cells. The differences between vegetative and reproductive cells therefore appear to be in matters of detail ; and spindle-formation in both, so far as investigated, agrees with the general scheme just outlined. Few of the details are known as yet in any case of intra- nuclear spindle-formation ; but the above outline would certainly require modification in order to fit these cases, at least in so far as concerns the place of initial appearance and activity of the kinoplasm. That a certain parallelism, how- ever, holds between the two methods is shown by Murrill’s observation that in the first segmentation of the egg of Tsuga , an intra-nuclear multipolar spindle occurs, which becomes bluntly bipolar ; and by Strasburger’s (’00) description, in vegetative cells of Lilium and Viscum , of an intra-nuclear multipolar diarch 4 Spindel-Anlage.’ Several cases have been noticed which seem to diverge still more greatly from the usual history of the building of the spindle. Such are its formation entirely out of the nucleole, x % 300 Allen . — The Early Stages of Sphidle- Formation according to Stevens (’98), in the pollen-mother-cell of As- clepias ; the origin of the fibres, as described by Murrill (’00), in the central cell of the archegonium of Tsuga , from two unequal polar kinoplasmic masses ; and the instance described by Miss Ferguson (’01) in the division of the generative nucleus of Pinus , where the spindle arises as a cone of fibres from a single cytoplasmic condensation below the nucleus, the latter lying close to the upper boundary of the cell. But such cases seem to be quite unusual, and it may be that further investigation will harmonize these with what are apparently more typical instances of spindle-formation. I have spoken of the cytoplasm in the early stages as composed apparently of a kinoplasmic network with empty meshes. The spaces between the fibres are of course filled, as the turgor of the cell shows, and it seems improbable that they are occupied only by a lifeless cell-sap. In later stages there is plainly an orange-staining inter-fibrous substance, granular rather than alveolar in structure, but in the earliest preparations I have not succeeded, by any variation of the staining process, in finding a trace of colour in the cytoplasm outside of the fibres. I have also been convinced from a careful study of Flemming and Vom Rath preparations that the fibrous appearance is not a precipitation result. Still earlier preparations of the developing male cones will be necessary to throw further light upon the cytoplasmic structures. As has been said, the great preponderance of evidence is opposed to the existence of centrosomes in the higher plants ; and conditions in the Larch seem to justify us in saying that here the possibility of a centrosome, in the sense of a directive organ, is excluded. Not only is no such body to be seen at any stage, but, if my observations are at all correct, there is no room to assume its operation. The fibres change their position without reference to any centre or to any definite number of centres. If centrosomes determine the radial arrangement, for example, we must imagine either as many centrosomes as there are radial fibres, or else a single centro- some somewhere within the nucleus ; and when the multipolar in ike Pollen- Mother-Cells of Larix. 301 figure appears, we must assume either that the many centro- somes have now fused into relatively few, or that the one has passed from the nucleus out into the cytoplasm and there has divided into ten, twelve, fifteen, or twenty. It seems evident from such considerations that the assumption of the possible presence of organs like the animal centrosome in the cells in question involves an ignoring of the best-established facts. The impression is given by a study of the arrangements and rearrangements of the kinoplasm that the activities con- cerned in the formation of the spindle centre in, or have reference to, the nucleus. Such an impression led Nemec (’98 b) to the hypothesis that the nucleus, in cells without a centrosome, is ‘ homo-dynamic 5 with the centrosome where it occurs. It is true that the ultimate function of the fibres, in the completed spindle, has reference to certain nuclear constituents — the chromosomes. From the generally accepted notion of the nucleus as the bearer of hereditary qualities, it follows, too, that that organ is the ultimate source of the stimuli which determine the synthetic processes of the cell ; and this hypothesis is borne out by a considerable mass of experimental evidence (Wilson, ’00 ; Gerassimow, ’01 ; &c.). It is quite possible, therefore, to suppose that the ultimate directive agencies for the growth and even for the arrangement of the kinoplasm, as of other cell-constituents, may finally be traced to the nucleus. But this is very different from saying that the present seat of the energy which is manifested in the movement of a particular fibre is within the nucleus ; and it seems to me that the facts which we have been con- sidering are inexplicable on the basis of the latter assumption. It might be imagined that the nucleus, acting like an immense centrosphere, should produce some such system of rays as appears in Fig. 6 ; but that it should, by exerting an influence at all comparable to the supposed action of a central body, be directly concerned in the metamorphosis of the early reticulum into a radial system, or in developing from the latter a felt, a multipolar or a bipolar spindle, seems quite inconceivable. 302 Allen . — The Early Stages of Spindle- Formation All of my observations are opposed to the notion that the kinoplasmic fibres are only { lines of force,’ or that they are, as Farmer (’95 b ) expresses it, simply hyaline protoplasm which has become strained along such lines of force. The appearance of the fibres throughout their history, their stain- ing properties, their powers of movement and contraction, all set them off as distinct from the surrounding cytoplasm, and argue in favour of their chemical and physical differentiation. The well-known formation of asters about the blepharoplasts points in the same direction ; for the same organs later form cilia which certainly closely resemble, if they are not essen- tially identical with, the intracellular fibres. Farmer (’95 b , p. 475) found that the fibres of the polar aster in Fossombronia extended as stiff projections beyond the broken edge of a cell which had been injured in cutting. In some preparations of my own of the dividing pollen-mother-cells of Lilium , there are numerous cases in which, after the first nuclear division and the formation and splitting of the cell-plate, some of the fibres of the central spindle may still be seen stretching, as densely stained strands, across the gap between the daughter-cells. Such facts appear consistent only with the actual existence of the fibres as differentiated structures. This specialized fibrous constituent of the cytoplasm seems to be, as has often been pointed out, the more active element of the cell ; the fibres in many ways display energy ; they change their position in the cell ; they bend and straighten themselves ; they extend into the nuclear cavity, are attached to the chromosomes, and appear to pull these bodies out into close proximity to the nuclear membrane ; when the latter disappears, the fibres arrange themselves into a figure of definite form, the bipolar spindle ; they apparently pull the chromosomes into the equatorial plate, and from this situation draw the daughter-chromosomes toward the poles. These activities suggest an analogy, if not a close relationship, between the fibres in question and the cilia of motile cells, and perhaps even a relationship with the contractile elements of muscle-fibres. Since, as has been . noted, there is no 303 in the Pollen- Mother - Cells of Larix . evidence that the activity of the fibres is under the influence of a central body, or, directly at least, under that of the nucleus, it follows as the most plausible explanation that the fibres are self-motile — that is, that they are themselves the seat of the energy which they manifest. If, then, the central body, where it exists, really has the function of direct- ing the processes of spindle-building, this particular function seems, in the higher plants, to have been transferred to the fibres themselves. Other functions which have been ascribed to the central body — either the attraction-sphere with its included centro- some, or one of these parts, the sphere or centrosome, occurring without the other — must also be served, in the Seed Plants, by other organs of the cell. Such functions may be included under three heads : the central body has been conceived as furnishing a reserve supply of kinoplasm ; as serving as a centre for the building of kinoplasmic fibres ; and as pro- viding for the fibres a point of insertion — the spindle-pole. As to the first function, Boveri (’88) found that the attrac- tion-sphere, exclusive of its central granule, is a mass of kinoplasm which is used, wholly or partly, in the building of the aster. Other bodies than the attraction-sphere, how- ever, have been found to serve, in various cells, the same purpose — 1 archoplasm-spheres,’ the ‘Nebenkern’ of animal spermatozoa, and, as Strasburger has long contended (’00, pp. 124 ff., for rlsuml)) the nucleole. Watasd (’93) has sought to show that centrosomes, microsomes, the ‘ Zwischenkorper ’ of animal cells and the cell-plates of plants are all aggregations of a similar cytoplasmic material. The experiments of Hottes and Nemec show that, under the influence of stimuli which retard the activity of the kinoplasmic fibres, the fibrous substance tends to round up into bodies of various size, from that of granules or ‘ cyto-microsomes ’ to that of ‘ extra-nuclear nucleoles ’ ; and Hottes shows that at higher temperatures the extra-nuclear nucleoles seem to be transformed into fibres, while cooling checks kinoplasmic activity and induces the re-formation of nucleolar bodies. Nemec (’01) has shown, 304 Allen . — The Early Stages of Spindle- Formation too, that In the higher plants other extra-nuclear masses, probably of kinoplasmic nature, sometimes occur. These facts, as well as the frequent appearance under normal con- ditions, at certain stages of mitosis, of extra-nuclear nucleoles, suggest that in plant-cells this function of the attraction- sphere is served by other organs, very probably in part at least by the nucleole, in part too, pefhaps, by other and less permanent bodies. The second function of the central body, that of furnishing a centre for the formation of kinoplasmic fibres, seems to be rendered unnecessary in the cells of the higher plants ; at least the evidence shows that spindle-formation in these plants may go on in the absence of a specialized organ which acts as a centre. It is true, we may think of a great number of centres of growth scattered throughout the cytoplasm ; but this conception is radically different from that of the centrosome, and is perhaps, in the present state of knowledge, one of little real value. On the basis of observed facts, it seems safe only to say that the forces involved in fibre- formation, instead of being centred about one or two points, are diffused throughout the cell. This is in harmony with the fact already noticed, that, after the formation of the fibres, their activities have no reference to any centre or to any limited number of centres. The other office of the central body, that of serving as a point of insertion for the spindle-fibres, seems also to be dispensed with in many instances. Many figures found in plant-cells recall the barrel-shaped polar spindles of A scar is (Boveri, ’87 ; Hacker, ’97). Very similar spindles are found by Fairchild (’97) in Basidiobolus , in which case, as in Ascaris , the fibre-bundles end in granules ; a barrel-shaped spindle is described in Spirogyra by many writers (see Strasburger, ’88, and Mitzkewitsch, ’98) ; and among the Seed Plants, spindles which remain throughout their history blunt or barrel-shaped are described by Strasburger (’88) in the endo- sperm of Dictamnus ; by Mottier ’(97) in the pollen-mother- cell of Podophyllum ; in that of Convallaria by Wiegand (’99) ; in the Pollen- Mother- Cells of Larix . 305 in the division of the central archegonial cell of Cycas by Ikeno (’96, ’98), of Finns by Blackman (’98), and of Zamia by Webber (’01) ; in the segmentation of the eggs of Cycas and Ginkgo by Ikeno (’98, ’01), and of those of Cephalotaxus by Arnold! (’00) ; and in the cells of wounded potato tubers by Nemec (’99 c). In the division of the generative nucleus of Potamogeton , Wiegand (’99) finds that one pole, attached to the cell-wall, is very broad, the other sharp. In the Larch we have seen that the fibres converge to a limited polar region, but not to a definite point. Evidently, if, by their contraction, the spindle-fibres are to pull apart the daughter-chromosomes, they must have some attachment or anchorage for their polar ends. This purpose we may imagine to be well served by a special body to which they all converge, provided that body have itself some means of attachment ; but the instances just cited show that the cells of many organisms, including those of higher plants, have secured means of insertion for their spindle-fibres in the absence of such a definite body, and often without even a marked convergence toward a polar region. Strasburger (’00) shows that in some cases a point of attachment is found in the plasma-membrane ; but in many others, the fibres seem to end in the cytoplasm, whose substance in this region we must suppose is adapted to furnish an anchorage for the contracting fibres. It would seem, then, that the cells of the higher plants have either found other organs to replace the centrosome, or that they have found means to dispense with its functions entirely and to arrive at substantially the same results by quite different methods. I shall not attempt to criticize the centrosome theory except as applied to the higher plants ; but it is evident that the whole centrosome question for the animal cell is at present an open one ; and such problems as the persistence of this organ through succeeding cell generations and its significance in nuclear division are still far from settled (Conklin, ’98 ; Gardiner, ’98 ; Mead, ’98 a). As to the energy manifested by the kinoplasmic fibres, it 306 Allen . — The Early Stages of Spindle- Formation seems highly probable that it is located within the fibres themselves, and that its source is to be sought in chemical transformations — destructive metabolism — occurring in the substance of the fibre concerned. Since the volume of the kinoplasm remains relatively constant during considerable periods, constructive metabolism must go on side by side with the destructive process ; the kinoplasm, then, in a period of activity, is to be thought of as in a condition of more or less rapid change ; it is being built up at the expense of some of the surrounding non-fibrous substance, perhaps of already living cell-constituents, perhaps of non-living but complex foods. The energy displayed by a particular fibre represents the difference between the energy of formation of the food which it receives, and that of the waste products which result from the destruction of its substance. It then becomes possible to define an active kinoplasmic fibre as the area within which certain energy-changes are occurring ; and the mass of the fibre is the sum of the masses of the substances within that area at the present moment, some of which are being built up, some being torn down, while still others may remain for a greater or less period unchanged. This notion of the nature of kinoplasm seems to be, as far as it goes, identical with the suggestion of Wilson (’95), when he defines a cell-organ as ‘ a differentiated area of the cell- substance in which a specific form of chemical change occurs.’ From this point of view, too, it is correct to say that the spindle-fibres are expressions of forces at work within the cell ; but while admitting the possibility of defining certain organs from the point of view of the energy-changes occurring in them, I think it is important to insist upon the mass of evidence already referred to which points to the existence of a distinct fibre-substance. The fibres, that is, are something more than paths or lines of force, or mere expressions of strains and stresses ; they are organs built up of a substance or of substances with distinctive chemical and physical pro- perties, which properties determine the power of the organ to do particular kinds of work. The organ owes its existence in the P ollen-Mother-Cells of Larix . 307 to certain chemical processes, and it does its work by means of the energy set free by these or by other chemical processes ; but it is also a machine, adapted by its structure to utilize in a definite way the energy so liberated. The investigations here described were begun at the sugges- tion of Professor R. A. Harper, and have been carried on with the continued assistance of his direction and criticism. Madison, Wisconsin. June 17, 1902. A lien.' — The Early Stages of Spindle-Formation 308 Literature Cited. Andrews, F. M. (’01) : Karyokinesis in Magnolia and Liriodendron , with special reference to the behaviour of the chromosomes. Beih. z. Bot. Centralbl., Bd. xi, p. 134. Arnoldi, W. (’00) : Beitrage zur Morphologic der Gymnospermen. III. Flora, Bd. lxxxvii, p. 46. Atkinson, G. F. (’99) : Studies on reduction in plants. Bot. Gaz., vol. xxviii, p. 1. Belajeff, W. (’94) : Zur Kenntniss der Karyokinese bei den Pflanzen. Flora, Bd. Ixxix, p. 430. Blackman, V. H. (’98): On the cytological features of fertilization and related phenomena in Pinus silvestris , L. Phil. Trans. Roy. Soc., B, vol. cxc, P- 395- Boveri, T. (’87) : Zellenstudien, Heft 1. Jena. (’88) : Zellenstudien, Heft 2. Jena. Byxbee, E. S. (’00) : The development of the karyokinetic spindle in the pollen- mother-cells of Lavatera. Proc. Cal. Acad. Sci., 3rd ser., Bot., vol. ii, P- 63. Campbell, D. H. (’95) : The structure and development of the mosses and ferns. New York. Conklin, E. G. (’98) : The asters in fertilization and cleavage (abstract of paper). Sci., N. S., vol. vii, p. 224. Davis, B. M. (’99) : The spore-mother-cell of Anthoceros. Bot. Gaz., vol. xxviii, p. 89. (’01) : Nuclear studies on Pellia. Ann. of Bot., vol. xv, p. 147. Debski, B. (’98) : Weitere Beobachtungen an Chara fragilis, Desv. Jahrb. f. wiss. Bot., Bd. xxxii, p. 635. Demoor, J. (’95) : Contribution a 1’etude de la physiologie de la cellule. Arch, d. Biol., tom. xiii, p. 163. Cited by Ngmec, ’99 d. Duggar, B. M. (’99) : On the development of the pollen-grain and the embryo- sac in Bignonia venusta . Bull. Tor. Bot. Club, vol. xxvi, p. 89. - — - — — — (’00) : Studies in the development of the pollen-grain in Sy?nplocarpus foetidus and Peltandra undulala. Bot. Gaz., vol. xxix, p. 81. Fairchild, D. G. (’97) : Ueber Kemtheilung und Befruchtung bei Basidiobolus ranarum, Eidam. Jahrb. f. wiss. Bot., Bd. Xxx, p. 285. Farmer, J. B. (’93) : On nuclear division in the pollen-mother-cells of Lilium Marlagon. Ann. of Bot., vol. vii, p. 392. — (’94) : Studies in Hepaticae : On Pallavicinia decipkns , Mitten. Ann. of Bot., vol. viii, p. 35. - — (’95 d) : Spore-foimation and karyokinesis in Hepaticae. Ann. of Bot., vol. ix, p. 363. — (’95 b) : On spore-formation and nuclear division in the Hepaticae. Ann. of Bot., vol. ix, p. 469. (’95 c) : Further investigations on spore-formation in Fegatella conica. Ann. of Bot., vol. ix, p. 666. in the Pollen-Mother- Cells of Larix . 309 Farmer, J. B. (’95 d): Ueber Kerntheilung in Li Hum- AxiXhexen, besonders in Bezug auf die Centrosomen-Frage. Flora, Bd. Ixxx, p. 56. Ferguson, M. C. (’01) : The development of the pollen 'tube and the division of the generative nucleus in certain species of pines. Ann. of Bot., vol. xv, p. 193. Fullmer, E. L. (’98) : Cell-division in pine seedlings. Bot. Gaz., vol. xxvi, p. 239. “ (’99) : The development of the microsporangia and microspores of Hemerocallis fulva. Bot. Gaz., vol. xxviii, p. 81. Gardiner, E. G. (’98) : The growth of the ovum, formation of the polar bodies, and the fertilization in Polychoerus caudatus. Journ. of Morph., vol. xv, P ' 73> Gerassimow, J. J. (’01) : Ueber den Einflluss des Kerns auf das Wachsthum der Zelle. Moscow. Guignard,oL. (’91a): Sur l’existence des ‘spheres attractives’ dans les cellules veg&ales. Compt. Rend., tom. cxii, p. 539. — (’91 b) : Sur la nature morphologique du phenomene de la feconda- tion. Compt. Rend., tom. cxii, p. 1320. (’91 c) : Nouvelles etudes sur la fecondation. Ann. Sci. Nat., Bot., 7 e sdr., tom. xiv, p. 163. (’97 a) : Les centrosomes chez les v^getaux. Compt. Rend., tom. cxxv, p. 1148. ■ (’97 b ) : Les centres cinetiques chez les v^getaux. Ann. Sci. Nat., Bot., 8 e ser., tom. vi, p. 177. (’98): Centrosomes in plants. Bot. Gaz., vol. xxv, p. 158. Hacker, V. (’97) : Ueber weitere Uebereinstimmungen zwischen den Fortpflan- zungsvorgangen der Tiere und Pflanzen. Biol. Centralbl., Bd. xvii, p. 689. Hof, A. C. (’98) : Histologische Studien an Vegetationspunkten. Bot. Centralbl., Bd. lxxvi, p. 65. Ikeno, S. (’96) : Note preliminaire sur la formation de la cellule de canal chez le Cycas revoluta. Bot. Mag. Tokyo, tom. x, p. 287. Cited by Webber, ’01, p. 89. (’98) : Untersuchungen liber die Entwickelung der Geschlechtsorgane und den Vorgang der Befruchtung bei Cycas revoluta. Jahrb. f. wiss. Bot., Bd. xxxii, p. 557. (’01) : Contribution a l’etude de la fecondation chez le Ginkgo biloba. Ann. Sci. Nat., Bot., 8 e ser., tom. xiii, p. 305. Juel, H. O. (’97) : Die Kerntheilungen in den Pollenmutterzellen von Hemerocallis fulva und die bei denselben auftretenden Unregelmassigkeiten. Jahrb. f. wiss. Bot., Bd. xxx, p. 205. Lawson, A. A. (’98) : Some observations on the development of the karyokinetic spindle in the pollen-mother-cells of Cobaea scandens , Cav. Proc. Cal. Acad. Sci., 3rd ser., Bot., vol. i, p. 169. (’00) : Origin of the cones of the multipolar spindle in Gladiolus. Bot. Gaz., vol. xxx, p. 145. McComb, A. (’00) : The development of the karyokinetic spindle in vegetative cells of higher plants. Bull. Tor. Bot. Club, vol. xxvii, p. 451. Mead, A. D. (’98 a) : The rate of cell-division and the function of the centrosome. Biol. Lect., 1896-7, Mar. Biol. Lab., p. 203. Boston. 3io A lien. — The Early Stages of Spindle- Formation Mead, A. D. (’98 b) : The origin and behaviour of the centrosomes in the annelid egg. Journ. of Morph., vol. xiv, p. 181. Mitzkewitsch, L. (’98) : Ueber die Kerntheilung bei Spirogyra. Flora, Bd. Ixxxv, p. 8i. Moore, J. E. S. (’94) : Some points on the origin of the reproductive cells in Apus and Branchipus. Quart. Journ. Micr. Sci., vol. v, p. 35. Cited by Hacker, ’97, p. 722. Morgan, T. H. (’96) : The production of artificial archoplasmic centres (abstract of paper). Sci., N. S., vol. iii, p. 59. Mottier, D. M. (’97) : Beitrage zur Kenntniss der Kerntheilung in den Pollen- mutterzellen einiger Dikotylen und Monokotylen. Jahrb. f. wiss. Bot, Bd. xxx, p. 169. (’98) : Ueber das Verhalten der Kerne bei der Entwickelung des Embryosacks und die Vorgangebei der Befruchtung. Jahrb. f. wiss. Bot., Bd. xxxi, p. 125. Murrill, W. A. (’00) : The development of the archegonium and fertilization in the hemlock spruce ( Tsuga Canadensis , Carr). Ann. of Bot., vol. xiv, p. 583. N£mec, B. (’97) : Cytologische Untersuchungen an Vegetationspunkten der Pflanzen. Sitzber. d. kon. bohm. Ges. d. Wiss., Prag, 1897, Bd. xxxiii, p. 25. (’98 a ) : Ueber die Ausbildung der achromatischen Kerntheilungsfigur im vegetativen und Fortpflanzungsgewebe der hoheren Pflanzen. Bot. Centralbl., Bd. lxxiv, p. 1. (’98 b ) : Ueber das Centrosoma der tierischen Zellen und die homo- dynamen Organe bei den Pflanzen. Anat. Anz., Bd. xiv, p. 569. (’99 a) : Zur Physiologie der Kern- und Zelltheilung. Bot. Centralbl., Bd. lxxvii, p. 241. (’99 b ) : Ueber die karyokinetische Kerntheilung in der Wurzelspitze von Allium cepa . Jahrb. f. wiss. Bot., Bd. xxxiii, p. 313. (’99 c) : Ueber Kern- und Zelltheilung bei Solanum tuberosum. Flora, Bd. lxxxvi, p. 214. (’99 d) : Ueber den Einfluss niedriger Temperaturen auf meristematische Gewebe. Sitzber. d. kon. bohm. Ges. d. Wiss., 1899, Bd. xii, p. 1. (’01) : Ueber centrosomahnliche Gebilde in vegetativen Zellen der Gefasspflanzen. Ber. d. dent. bot. Ges., Bd. xix, p. 301. Osterhout, W. J. V. (’97) : Ueber Entstehung der karyokinetischen Spindel bei Equisetum. Jahrb. f. wiss. Bot., Bd. xxx, p. 159. Rosen, F. (’95) : Beitrage zur Kenntniss der Pflanzenzellen. Cohn’s Beitr. z. Biol. d. Pflanzen, Bd. vii, p. 225. Sargant, E. (’97) : The formation of the sexual nuclei in Lilium Martagon. II. Spermatogenesis. Ann. of Bot., vol. xi, p. 187. Schaffner, J. H. (’98) : Karyokinesis in the root-tips of Allitun cepa. Bot. Gaz., vol. xxvi, p. 225. (’01) : A contribution to the life-history and cytology of Erythronium. Bot. Gaz., vol. xxxi, p. 369. Schniewind-Thies, J. (’01) : Die Reduktion der Chromosomenzahl und die ihr folgenden Kemteilungen in den Embryosackmutterzellen der Angio- spermen. Jena. in the Pollen- Mother-Cells of Larix . 31 1 Smith, R. W. (’00 a) : The structure and development of the sporophylls and sporangia of Isoetes. Bot. Gaz., vol. xxix, p. 225. (’00 h ) : The achromatic spindle in the spore-mother- cells of Osmunda regalis. Bot. Gaz., vol. xxx, p. 361. Stevens, W. C. (’98) : The behaviour of kinoplasm and nucleolus in the division of the pollen-mother-cells of Asclepias Cornuti . Kansas Univ. Quart., vol. vii, p. 77. Strasburger, E. (’80) : Zellbildung und Zelltheilung. Dritte Aufl. Jena. • (’88) : Ueber Kern- und Zelltheilung im Pflanzenreiche. Hist. Beitr., Bd. i. Jena. (’95) : Karyokinetische Probleme. Jahrb. f. wiss. Bot., Bd. xxviii, p. 1 5 1. (’00) : Ueber Reduktion stheilung , Spindelbildung, Centro- somen und Cilienbildner im Pflanzenreich. Hist. Beitr., Bd. vi. Jena. (’01) : Einige Bemerkungen zu der Pollenbildung bei Asclepias. Ber. d. deut. bot. Ges., Bd. xix, p. 450. Watas£, S. (’93) : Homology of the centrosome. Journ. of Morph., vol. viii, P- 433- Webber, H. J. (’01) : Spermatogenesis and fecundation of Zamia. U. S. Dept, of Agric., Bureau of Plant Industry, Bull. No. 2. WlEGAND, K. M. (’99) : The development of the microsporangium and micro- spores in Convallaria and Potamogeton. Bot. Gaz., vol. xxviii, p. 328. Williams, C. L. (’99) : The origin of the karyokinetic spindle in Passiflora coerulea, Linn. Proc. Cal. Acad. Sci., 3rd ser., Bot., vol. i, p. 189. Wilson, E. B. (’95) : Archoplasm, centrosome and chromatin in the sea-urchin egg. Journ. of Morph., vol. xi, p. 443. (’00) : The cell in development and inheritance, 2nd ed. New York. 312 Allen— The Pollen- Mot her -Cells of Larix. EXPLANATION OF FIGURES IN PLATES XIV and XV. Illustrating Mr. Allen’s paper on the Pollen-Mother-Cells of Larix. All the figures were drawn with the aid of the camera lucida , and with a Zeiss apochromatic 2 mm. objective, 1-30 apert. ; all except Fig. 4, PI. XIV, with compens. oc. 8 ; Fig. 4, with compens. oc. 1 2. PLATE XIV. Fig. i. Cross-section of pollen-mother- cell of Larix europaea , DC., material gathered and fixed October 24 ; very early prophases, showing fibrous network in the cytoplasm. Fig. 2. Cell fixed March 15 following; an inter- fibrous material is new present. Fig. 3. Somewhat later stage, with rather thick cell-wall. Fig. 4. Small part of section of cell at same stage, cut tangentially to the nucleus; membrane not visible; the dark rounded bodies are chromatin, the lighter shaded masses linin ; fibres can be traced from the chromatin bodies into continuity with the cytoplasmic network. Fig. 5. A cell from the same section as Figs. 3 and 4 ; the cytoplasmic fibres have taken on a radial arrangement. Fig. 6. Radial stage, fibres running from nuclear membrane to plasma membrane. Fig. 7. Beginning of folding-over of fibres. Fig. 8. Fibres are gathering into felt just outside nucleus ; many extra-nuclear nucleoles present. Fig. 9. A cell somewhat shrunken, with the nuclear membrane plasmolysed and pushed inward. Figs. 10 and n. Later stages in the formation of the felt. PLATE XV. Fig. 12. The completed felt; nuclear membrane much folded, probably on the point of dissolution ; nucleole vacuolated. Fig. 13. The nuclear membrane has disappeared; nuclear cavity contains granular fibres of nuclear origin ; the outer fibres are being oriented to form the cones of the multipolar spindle. Figs. 14 and 15. Later stages in the formation of the multipolar spindle. In Fig. 15 the fibres are gathered into bundles which run from the poles to the chromosomes. Fig. 16. A multipolar figure ; the cell somewhat shrunken and plasmolysed ; a peripheral zone containing fibres and irregular * cyto-asters.’ Fig. 1 7. The fibres becoming straightened out and parallel ; a transition to the bipolar spindle. Fig. 18. A ‘ multipolar diarch ’ stage. Fig. 19. A completed spindle in the equatorial plate stage, showing polar radiations. Fig. 20. The diaster stage ; a few especially dense fibres or strands in the central spindle ; the polar radiations very numerous. JtnjwuLs ofBotcmy. ALLEN.— POLLEN-MO THER-CELLS OF LAR1X. Vol XVIL FLAW. Univ er sity Pt e ss, Oxf or d. ftnn/jds of Botany. Vol.XVIlPl.XIV University Press, Oxford. I ALLEN.— POLLEN-MOTHER-CELLS OF LARIX. ftniuxls of Botouny. Fig. 12. C.E.A. del. Vol.XVILPl.Xl ’re s.s, Oxford. ftrvnods of Botany. Vol.XVIiPL.Xl. University Press, Oxford. ALLEN.— POLLEN- MO THER-CELLS OF LARIX. Flowers and Insects in Great Britain Part II 1 . Observations on the Natural Orders Dipsaceae, Plumb a- ginaceae, Compositae, Umbelliferae, and Cornaceae, made in the Clova Mountains. BY J. C. WILLIS, M.A., Director of the Royal Botanic Gardens , Ceylon. AND I. H. BURKILL, M.A., Assistant Reporter on Economic Products to the Government of India. I N Part I of this series 1 we described the results of work in the more southern and lowland districts of Britain; the present and following papers deal with the flowers and insects of a definite area in the Eastern Grampians of Scotland, and form a contribution to the study of the problem of the com- position, distribution, and origin of the flora of that region and its interdependence with those of the insect fauna. Numerous factors have been active in producing the present phenomena of the vegetation of Northern Europe, and among them the floral ecology of the plants concerned has doubtless been one of much importance ; its share may best be deter- mined by comparative work upon limited areas in different parts of Europe. Our observations were made during vacations spent at Clova between 1894 and 1899. We selected Clova for our 1 Pt. i, see Ann. of Bot., vol. ix, p. 227, 1895. [Annals of Botany, Vol. XVII. No. LXVI. March, 1903.] Y 314 Willis and Bur kill, — Flozvers and work because it is the focus of the distribution of Alpine plants in Britain, and because of special facilities for our work which the owners of the land there gave us. To them we owe our sincere thanks. The Clova district as here described means the southern face of the Grampians near Clova in Forfarshire, and includes the upper parts of Glens Clova and Prosen, and the moors of the North Esk above Loch Lee. It comprises about 103^ square miles, and forms three fairly well defined zones, a zone of straths or valley bottoms (500-1000 feet elevation, 9 sq. miles), a zone of steep hillsides, usually broken by crags above 1,800 feet (1,000-2,500 feet, 74 sq. miles), and a zone of open peaty moors above (2,500-3,000 feet, 20 sq. miles, with £ sq. mile above 3,000 feet). The total phanerogamic flora is 363 species, of which eighty-one are alpines ; sixteen other species are maintained by cultivation. Details of these, with discussion of seasonal and altitudinal distribution, are given elsewhere 1 . The insects which we collected have largely been named by the following entomologists, to whom we are very much indebted. G. C. Bicknell, Esq., F.E.S. (Parasitic Hymenoptera). H. J. Burkill, Esq., M.A. (Lepidoptera). P. Cameron, Esq., F.E.S. (Tenthredinidae). E. Saunders, Esq., F.E.S. (Hymenoptera aculeata). D. Sharp, Esq., M.B., F.R.S. (Coleoptera and others). G. H. Verrall, Esq., F.E.S. (Diptera). C. Warburton, esq., M.A. (Araneida). Our observations were distributed as much as possible over the months when flowers occur, August being alone neglected. An account of our visits and a summary of the Flora is given in the Transactions of the Edinburgh Botanical Society, cited below. Clova stands at about 780 feet above the sea, in a narrow valley between hills which rise rapidly to 2,500 feet, and in 1 Trans. Edin. Bot. Soc., xxii, 1901, p. 109. Insects in Great Britain . 3i5 a few instances just exceed 3,000 feet. Crags break the slopes between 2,000 and 2,500 feet. Above the crags stretch peaty moors, which late in the year justify the dreariness attributed to them by Continental writers. The straths or valley bottoms are as full of flowers and as full of insects as the moors are poor in both. It is part of our purpose to set before the reader a contrast of the two conditions. For the rest we shall compare the conditions of Flower Fertilization at Clova with Flower Fertilization in Germany, the Alps, and elsewhere. Except on our first two visits we kept a count of individuals visiting, and the record shows more clearly than any lists of visitors the importance of the various species. The count may be summed as follows, the desirability of the various groups to the flowers being indicated by the type, the larger the type the better suited for fertilizing the flowers 1 : — /APIS (Apidae) BOMBUS and PSITHYRUS (Apidae) . ANDRENA ( 66 ), HALICTUS (i), AND NOMADA (i) (Apidae) ODYNERUS (5) AND CHRYSIS (l) ( = PETIOLATA TUBULIFERA) Vespidae (Wasps) ....... Formicidae and Myrmicidae (Ants) Tenthredmidae (Sawjlies) . ' Parasitic Hymmoptera (Petiolata parasitica) 430 937 68 6 45 202 201 461 3 * ■& (RHOPALOCERA NOCTUIDAE and GEOMETRES . BOMBYCES AND MICROLEPIDOPTERA generally ^Eriocephala ....... 192 204 64 101 Carried forward 2,911 1 Large capitals denote decidedly desirable insects or groups of insects, small capitals denote desirable ; small roman letters denote indifferent, and small italics denote injurious visits. The grouping closely agrees with Loew’s classification of Anthophilous insects into Eutropous, Hemitropous, Allotropous and Dystropous. 3i6 Willis and Bur kill. —Flowers and Brought forward . 2,911 /SYRPHIDAE .... . 712 EMPIS (41 1), AND PACHYMERIA (i6) . . . 427 J Other Empidae Muscidae (in restricted sense), Tachinidae and 129 Sarcophagidae . . i ,°8 3 \Other Diptera . 10,321 Coleoptera .... . I 3 I 4 Other Insects .... 409 17,306 In this part of our paper, taking the Compositae and their allied orders, and the Umbelliferae and their allied order Cornaceae, we shall show what part of the whole available insect fauna these orders with more or less massed flowers may be considered to attract. The third part will deal with the most highly specialized plants of the Clova Flora ; and the fourth will contain an account of the least specialized Entomophilous plants together with a review of the whole results. Abbreviations. In references. Brit. — The British Isles. N.C.E. — North Central Europe (Europe south of the North Sea and Baltic and north of the Alps). Arct. — Arctic regions. Observations chiefly in Green- land and Arctic Scandinavia. Pyren . = Pyrenees. Medit. — Mediterranean countries. N.Am. = North America. Scand. — Lowland Scandinavia. In lists. sh. = sucking honey, fp. = feeding on pollen, cp. = collecting pollen. Insects in Great Britain . 317 And in tables : — HI., Lep.l. = long-tongued Hymenoptera and Lepidoptera respectively. Hm., Lep.m., and Dm. = mid-tongued Hymenoptera, Lepido- ptera, and Diptera respectively. Hs., Lep.s., and Ds. = short-tongued Hymenoptera, Lepi- doptera, and Diptera respectively. We have found it necessary to modify the literature list which was given in the first part of our paper, but in the new one while we have added and omitted titles we have preserved the numbers used before for all entries that are retained. This list follows Literature. 1. Bibliography. Knuth, P. : Handbuch der Bliitenbiologie. Vol. I, pp. 263-381, Leipzig, 1898. Numbers following names of authors refer to this. II. Books and Papers . !. Miller, H. : Fertilization of Flowers, English edition. (London, 1883.) 2. — : Alpenblumen. (Leipzig, 1881.) 3. — : Weitere Beobachtungen liber Befruchtung der Blumen durch Insekten. (3 a : Verhandlungen d. nat. V ereins d. preuss. Rheinlande und Westfalens, XXXV, 1878, pp. 272-329 ; 3 b, ditto, XXXVI, 1879, pp. 198-268 ; 3 c, ditto, XXXIX, 1882, pp. 1-104.) 4. Loew, E. : Bliitenbiologische Floristik. (Stuttgart, 1894.) 7. Ekstam : Zur Kenntniss d. Bliitenbestaubung auf Novaia Semlja. (Ofv. af Kongl. Vet. Ak. Forhandl. Stockholm, 1894, p. 79.) 8. Heinsius : Eenige waarnemingen en beschouwingen over de bestuiving van bloemen der Nederlandsche flora door in- secten. (Bot. Jaarboek, Gent, IV, 1892, p. 54.) 9. Keener, A., and Oliver, F. W. : Natural History of Plants. (London, 1894.) 10. Kirchner : Beitrage zur Biologic d. Bliiten. (Progr. d. 72. 3 1 8 Willis and Bur kill — Flowers and Jahresfeier d. kgl. wiirttemb. landwirthsch. Akad. Hohen- heim. Stuttgart, 1890.) 11. Knuth, P. : Blutenbiologische Herbstbeobachtungen. (Bot. Centralblatt, 49, 1892.) 12. : Vergl. Beobachtungen ii. d. Insektenbesuch an Pflanzen d. Sylter-Haide u. d. schleswigschen Festlands- haide. (Bot. Jaarboek, Gent, IV, 1892, p. 27.) 14. : Blumen u. Insekten auf d. nordfriesischen Inseln (Kiel, 1893) ; 14 a: Weitere Beobachtungen liber Blumen u. Insekten auf d. nordfriesischen Inseln. (Verh. d. natur- wissensch. Vereins fur Schleswig-Holstein, X, 1894, pp. 225-57-) 15. : Blumen u. Insekten auf d. Halligen. (Bot. Jaar- boek, Gent, VI, 1894.) 16 . Loew, E. : Beitrage zur bllitenbiologischen Statistik. (Abh. Bot. Vereins Brandenburg, XXXI, 1890, pp. 1-63.) 1 7. MacLeod, J. : De Pyreneeenbloemen en hare bevruchting door Insecten. (Bot. Jaarboek, Gent, III, 1891, p. 260.) 18. : Over de bevruchting d. bloemen in het Kempisch gedeelte van Vlaanderen. (Bot. Jaarboek, Gent, V, 1893, and VI, 1894.) 19. Robertson, C. : Flowers and Insects. (19 a, Bot. Gazette, XVII, p. 177; 19 b, ditto, XVIII, p. 269; 19 c, Trans. Acad. St. Louis, VI, p. 117; 19 d, ditto, VI, p. 475.) 21. Schulz, A.: Beitrage z. Kenntniss d. Bestaubungseinrichtungen u. d. Geschlechtsvertheilungen bei den Pflanzen. (Biblio- theca Bot., X, XVII. Cassel, 1889-90.) 23. Scott-Elliot, G. F. : Flora of Dumfriesshire. (Dumfries, 1896.) 24. Verhoeff: Biologische Beobachtungen auf d. Insel Norderney. (Abh. d. naturw. Vereins, Bremen, XII, 1891, p. 65.) 25. : Blumen u. Insekten auf d. Insel Norderney. (Nova Acta d. Kais. Leop.-Carol. deutsch. Akad. d. Naturf. Leipzig, 1894.) 26. Willis, J. C. : Gynodioecism in the Labiatae. (Proc. Cam- bridge Phil. Soc. 1892-93.) 29. Burkill, I. H. : Fertilization of Spring Flowers on the York- shire Coast. (Journ. Bot. 1897, pp. 92-9, 138-45, 184-9.) Insects in Great Britain . . 319 30 . Knuth, P. : Bluthenbiologische Beobachtungen in Thiiringen. (Bot. Jaarboek, Gent, VII, 1895, pp. 24-59.) 31 . : Blumen u. Insekten auf Helgoland. (Bot. Jaarboek, Gent, VIII, 1896, pp. 22-47.) 32 . : Bliitenbiologische Beobachtungen auf der Insel Riigen. (Bot. Jaarboek, Gent, IX, 1897, pp. 1-12.) 33 . : Bloemenbiologische Bijdragen. (Bot. Jaarboek, Gent, IX, 1897, pp. 13-61.) 34 . : Handbuch der Bliitenbiologie. Vol. 2. (Leipzig, 1898-99.) 35. ; Bliitenbiologische Notizen. Bloemenbiologische Aanteekeningen. (Bot. Jaarboek, Gent, X, 1898, pp. 36 - 59 ) 36 . Lindman, C. A. M. : Bidrag till Kannedomen om Skandinaviska fjallvaxternas blomning och befruktning. (Bihang till k. Sven- ska Vetensk. Akad. Handlingar, XII, afd. 3, No. 6, 1887.) 37 . Warming, E. : Biolog. optegnelser om Gronlandske Planter. (Bot. Tidsskrift : 37 a, XV, p. 151 ; 37 b, XVI, p. 1 ; 37 c, XVII, p. 202.) 38 . : Om Bygningen og den formodede Bestovnings- maade af nogle groenlandske Blomster. (Oversigt over d. k. D. Vidensk. Selsk. Forhandl. 1886.) 39 . Willis, J. C., and Burkill, I. H. Flowers and Insects in Great Britain. Part I. (Annals of Botany, 1895, pp. 227-73.) 40 . Alfken, D. : Erster Beitrag zur Insektenfauna der Nordseeinsel Juist. (Abhandl. d. naturw. Vereins, Bremen, XII, 1891, pp. 97 -I 30 -) B' § 1. Dipsaceae. 57. Scabiosa Succisa, Linn. [Lit. Brit. 23 , 39 ; Darwin 485 ; N.C.E. 1 , 3 c, 8, 14 , 14 a, 18 , 21 b, 33 , 34 , 40 ; De Vries 2460 , Magnus 1492 .] A Bombus-flower at Clova as else- where, with abundant visitors among the Syrphidae. We gave figures of the number of insects visiting it on the Scarborough cliffs in the first part of our paper ; there the Bombi make 55-3 per cent, of the visitors ; at Clova they make 38-2 per cent. Long-tongued flies appeared in greater numbers at Clova than at Scarborough. 320 Willis and BurkilL — Flowers and Visitors. Lepidoptera. Rhopalocera : (i) Polyommatus phloeas L., sh. 13. IX. 95, 700 ft. Heterocera: Nociuidae : (2) Celaena Haworthii Cue., 20. IX. 95, 900 ft. (3) Hydroecia nictitans Bkh., sh. 13. IX. 95, 700 ft. Hymenoptera. Aculeata: Apidae : (4) Apis mellifica L., sh. 19. IX. 95, 800 ft. (5) Bombus agrorum F., sh. 13-24. IX. 95, 7-1,200 ft. (6) B. lapidarius L., sh. 15. IX. 95, 800 ft. (7) B. pratorum L., sh. 22-23. VI. 95; 13. IX. 95, 7- 800 ft. (8) B. cognatus Steph., sh. 14. IX. 95, 800 ft. (9) B. terrestris L., sh. 13-24. IX. 95, 7-1,200 ft. * Diptera. Syrphidae : (10) Melanostoma mellinum L., fp. 16. IX. 95, 800 ft. (11) Platychirus manicatus Mg., fp. 23. VII. 95, 800 ft. (12) P. albimanus F., fp. 17. IX. 95, 700 ft. (13) Sericomyia lapponum L., sh. 13. IX. 95, 700 ft. (14) S. borealis Fin., sh. 13-24. IX. 95, 7-900 ft. (15) Eristalis tenax L., sh. 13. IX. 95, 700 ft. (16) E. pertinax Scop., sh. 13-24. IX. 95, 7-1.000 ft. and once at 2,300 ft. (17) Heliophilus pendulus L., sh. 24. IX. 95, 800 ft. Empidae\ (18) Empis tessellata F., sh. 13-22. IX. 95; 11. VII. 96, 7-1,000 ft. (19) E. grisea Fin., sh. 15-22. IX. 95, 800 ft. (20) Pachymeria palparis Egg., sh. 15-24. IX. 95, 800 ft. Tachinidae\ (21) Siphona geniculata Deg., sh. 13-19. IX. 95, 7-800 ft. Muscidae : (22) Lucilia cornicina F., sh. 19. IX. 95, 800 ft. (23) Pollenia rudis F., 14. IX. 95, 900 ft. Anthomyiidae : (24) Hyetodesia incana W., sh. and fp. 15-18. IX. 95, 8-1,300 ft. (25) Drymia hamata Fin., sh. 14-24. IX. 95, 800 ft. (26 and 27) Anthomyia 2 spp., sh. 14-24. IX. 95, 8- 900 ft. (28) Trichophthicus sp., 13. IX. 95, 700 ft. Cordyluridae : (29) Scatophaga stercoraria L., 16-23. IX. 95, 9-1,100 ft. Coleo- ptera: (30) Meligethes viridescens F., 15-18. IX. 95, 800 ft. Araneida: (31) Xysticus sp., lying in wait, 13. IX. 95, 700 ft. B' § %. Plumbaginaceae, with Aggregated Flowers. 58 . Armeria maritima, Willd. [Lit. Brit. 23; N.C.E. 1, 9, 12, 14, 14 a, 15, 21 a, 25, 31, 34, 35 ; Knuth 1221 ; MacLeod 1473. Pyren. 17 .] Only found at 12,890 feet, the flowers are 8-9 mm. in diameter. Visitors. Diptera. Cecidomyiidae'. (1) 1 sp. sh. 2. VII. 96. Mycetophilidae: (2) Sciara sp., ? sh. 16. VI. 99. Anthomyiidae'. (3) Trichophthicus sp., sh. fairly abundant 2. VII. 96; 16. VI. 99. Thysanoptera. (4) Thrips sp., 2. VII. 96. All at 2,800 ft. Insects in Great Britain. 321 B' § 3. Blue-flowered Compositae. 59. Centaurea Cyanus, Linn. [Lit. N.C.E. 1, 3 c, 9, 11, 14, 16, 18, 32, 34, 40.] Visitors. Hymenoptera. Aculeata: Apidae : (1) Andrena analis Panz., seeking h. Diptera. Anthomyiidae : (2) 1 sp. Both 11. VII. 96, 600 ft. 59 a. Lactuca alpina, Benth. [Lit. N.C.E. Loew 1358; Alps 2; Arct. 36.] At 2 ; oooft. The capitula contain 12-20 flowers, and number 16-20. The neighbouring flowers may pollinate each other, but self-pollination by the rolling back of the stigmatic lobes seems not to occur. In this our observations agree with those of Muller. We have had no favourable opportunities for observing visitors. B' § 4. Purple-flowered Compositae. 60. Centaurea nigra, Linn. [Lit. Brit. 23, 39 ; Marquand 1513; N.C.E. 8; Pyren. 17.] Visitors. Hymenoptera. Aculeata: Apidae : (1) Bombus terres- tris L., sh. 15-21. IX. 95, 8-900 ft. (2) B. agrorum F., sh. 15-21. IX. 95, 8-900 ft. (3) B. lapidarius L., sh. 16-22. IX. 95, 800 ft. (4) B. lapponicus F., 16. IX. 95, 800 ft. Diptera. Empidae'. (5) Empis grisea Fin., sh. 15-21. IX. 95, 800 ft. (6) Pachymeria pal- paris Egg., sh. 16. IX. 95, 800 ft. Anthomyiidae'. (7) Hyetodesia incana W., 16. IX. 95, 800 ft. (8) Drymia hamata Fin., sh. and fp. 15-16. IX. 95, 8-900 ft. (9) Anthomyia sp., sh. 21. IX. 95, 800 ft. Coleoptera : (10) Meligethes viridescens F., 15-16. IX. 95, 8-900 ft. 61. Carduus palustris, Willd. [Lit. Brit. 23 ; N.C.E. 1, 3 c, 8, 16, 18, 34, 40 ; De Vries 2460 ; Warnstorf 2507 ; Alps 2, 34.] Bombus terrestris and Empis tessellata show some measure of constancy in autumn. Visitors. Lepidoptera. Rhopalocera: (1) Argynnis aglaia L., sh. 29. VI.-i. VII. 95; 22. VI.-10. VII. 96, 8-900 ft. (2) Lycaena icarus Rott., sh. 28. VI. 95, 800 ft. Heterocera : Noduidae\ (3) Hydroecia nictitans Bkh., sh. 13-21. IX. 95, 7-1,000 ft. Hymeno- 322 Willis and Burkill, — Flowers and ptera. Aculeata : Apidae\ (4) Bombus terrestris L., 16-21. IX. 95, 7-1,400 ft. (5) B. agrorum F., sh. 1. VII. 95, 800 ft. (6) B. venus- tus Smith, sh. 26. VI. 96, 800 ft. (7) B. lapponicus F., 16. IX. 95, 1,400 ft. (8) Psithyrus quadricolor Lep., sh. 19. VI. 96, 1,500 ft. Formicidae'. (9) Formica fusca Latr., 22. VI. 96, 2,300 ft. Diptera. Syrphidae'. (10) Platychirus manicatus Mg., sh. 1-6. VII. 95, 800 ft. (11) Rhingia campestris Mg., sh. 1. VII. 95, 800 ft. (12) Volucella bombylans L., sh. 1. VII. 95, 800 ft. (13) Eristalis arbustorum L., sh. 19. VI. 95, 800 ft. Empidae\ (14) Empis tessellata F., sh. 2. VII. 95; 16-21. IX. 95; 19. VI. 96, 8-1,500 ft. Mycetophilidae\ (15) Sciara sp., 21. IX. 95, 1,000 ft. Anthomyiidae : (16) Hyeto- desia incana W., 1. VII. 95; 6. VII. 96, 800 ft. (17) Tricho- phthicus sp., 29. VI.-3. VII. 95 ; 16. IX. 95, 8-1,200 ft. (18 and 19) Anthomyia 2 spp., fp. 26. VI.-i. VII. 95; 21. IX. 95; 19. VI.-i. VII. 96, 8-1,500 ft. Coleoptera. (20) Ceuthorrhynchidius contrac- tus Marsh, 23. VI. 96, 2,500 ft. 62. Cnicus arvensis, Hoffm. [Lit. Brit. 23 ; N.C.E. 1, 3 c, 8, 11, 14, 14 a, 15, 16, 18, 25, 30, 31, 32, 33, 34, 40; De Vries 2460; Alps 2, 9, 34; Pyren. 17.] At Clova the more specialized visitors deficient. Visitors . Lepidoptera. Rhopalocera : (1) Vanessa urticae L., sh. 21. IX. 95, 1,200 ft. Heterocera: Noctuidae'. (2) Charaeas gra- minis L., sh. 14. IX. 95, 900 ft. Hymenoptera. Aculeata: Apidae : (3) Bombus terrestris L., 21-24. IX. 95, 9-1,200 ft. Petiolata parasi- tica: Ichneumonidae : (4) Hemiteles politus Bridgm., sh. 21. IX. 95, 900 ft. (5) a second sp., 17. IX. 95, 900 ft. Diptera. Syrphidae : (6) Eristalis pertinax Scop., sh. 21-24. IX. 95, 9-1,200 ft. Sarco- phagidae : (7) Cynomyia mortuorum L., sh. 14-24. IX. 95, 9-1,200 ft. Muscidae : (8) Lucilia cornicina F., sh. 21. IX. 95, 900 ft. (9) Calli- phora erythrocephala Mg., 24. IX. 95, 1,200 ft. (10) Pollenia rudis F., sh. and fp. 14-24. IX. 95, 9-1,200 ft. Anthomyiidae'. (11) Hyetodesia incana W., 21. IX. 95, 900 ft. (12 and 13) Anthomyia spp., fp. 17-21. IX. 95, 8-900 ft. Cordyluridae : (14) Scatophaga stercoraria L., sh. 21. IX. 95, 8-900 ft. Coleoptera: (15) Meli- gethes viridescens F., sh. 17-24. IX. 95, 8-900 ft. 63. Cnicus heterophyllus, Willd. [Lit. Brit. 23 ; N.C.E. 1 ; Loew 1359 ; Arct. 34 ; Alps 2.] Insects in Great Britain. 323 Visitors . Lepidoptera. Heterocera: Noctuidae: (1) Plusia chry- sitis L., sh. 2. VII. 96. Hymenoptera. Aculeata : Apidae\ (2) Apis mellifica L., sh. 3-1 1. VII. 96. (3) Bombus terrestris L., 2. VII. 95. (4) B. hortorum L., sh. 29. VI.-n. VII. 96. (5) B. pratorum L., sh. 11. VII. 96. (6) Psithyrus quadricolor Lep., sh. 22. VII. 95. Vespidae : (7) Vespa norvegica F., seeking h. 15. VII. 95. Diptera. Syrphidae : (8) Platychirus sp., fp. 22. IX. 95. (9) Sericomyia borealis Fin., fp. 8. VI. 95. (10) Volucella bombylans L., sh. 11. VII. 96. (11) Rhingia campestris Mg., 11. VII. 96. Empidae: (12) Empis sp., fp. 29. VI. 96. (13) E. aestiva Lw., fp. 29. VI. 96. Bihionidae: (14) Scatopse sp., ? seeking h. 3. VII. 96. Dolichopodidae'. (15) Dolichopus sp., sh. 3. VII. 96. Anthomyiidae\ (16) Hyetodesia incana W., fp. 22. IX. 95; 24. VII. 96. (17) Hy- lemyia nigrescens Rnd., 20. VI. 96. (18) Anthomyia sp., 22. IX. 95. Sciomyzidae : (19) Dryomyza flaveola Fin., 20. VI. 96. Sapromyzidae : (20) Sapromyza sp., 20. VI. 96. Coleoptera : (21) Meligethes viri- descens F., fp. 15-20. IX. 95; 29. VI. 96. (22) M. aeneus F., fp. 3. VII. 96. (23) Epuraea aestiva L., fp. 29. VI. 96. (24) Antho- bium sorbi Gyll., fp. 29. VI. 96. Hemiptera : (25) 1 sp., 3. VII. 96. Thysanoptera : (26) Thrips sp., 3. VII. 96. All at 7-800 ft. 64 . Cnicus lanceolatus, Scop. [Lit. Brit. 23 ; N.C.E. 1 , 3c, 8 , 11 , 14, 14a, 16, 18, 31, 33, 34, 40; DeVries 2460; Warnstorf 2507 ; Alps 2; Pyren. 17 ; N.Arn. 19 d.] Visitors . Hymenoptera. Aculeata: Apidae: (1) Bombus terres- tris L., sh. 21-23. IX. 95, 10-1,300 ft. (2) B. lapponicus F., sh. 21. IX. 95, 1,000 ft. (3) Psithyrus quadricolor Lep., sh. 21. IX. 95, 1,000 ft. Diptera. Syrphidae'. (4) Eristalis pertinax Scop., 13. IX. 95, 700 ft. Empidae\ (5) Empis tessellata F., 21. IX. 95, 1,000 ft. Phoridae'. (6) Phora sp., 17. IX. 95, 700 ft. Anthomyiidae : (7) Hyetodesia semicinerea W., 21. IX. 95, 1,000 ft. Hemiptera: (8) Aphis sp., 17. IX. 95, 700 ft. 65 . Saussurea alpina, DC. [Lit. Arct. 36 ; Alps 2, 9.] Visitors. Diptera. Anthomyiidae'. (1) Trichophthicus hirsutulus Ztt., fp. 15. VII. 95, 2,400 ft. (2) Anthomyia sp., fp. 18. VII. 95, 2,300 ft. 324 Willis and Bur kill. — Flowers and B' § 5. Yellow-flowered Rayed Compositae. 66 . Solidago Virg-aurea, Linn. [Lit. Brit. 23; N.C.E. 1, 11, 18, 33, 34, 40; Warnstorf 2507 ; Arct. 36 ; Alps 2, 34; Pyren. 17.] Visitors. Diptera. Tachinidae\ (1) Siphona geniculata Deg., fp. 1 6. IX. 95, 800 ft. Muscidae : (2) Calliphora erythrocephala Mg., 29. VI. 96, 800 ft. Anthomyiidae : (3) Hyetodesia incana W., 29. VI. 96, 800 ft. (4) Anthomyia sp., fp. 16. IX. 95, 800 ft. (5) Limno- phora solitaria Ztt., sh. 6-10. VII. 96, 21-2,600 ft. 67 . Tussilago Farfara, Linn. [Lit. Brit. 29 ; N.C.E. 1, 14, 18, 34, 40 ; Medit. 34 ; Arct. 34 ; Alps 2 , 9.] Visitors. Hymenoptera. Aculeata: Apidae: (1) Apis mellifica L., sh. 12-16. IV. 95, 800 ft. Diptera. Syrphidae : (2) Melanostoma quadrimaculatum Verrall, sh. 12. IV. 95, 800 ft. Muscidae'. (3) Lucilia cornicinaF., sh. 12-16. IV. 95, 800 ft. abundant. (4) Pollenia rudis F., sh. 12-16. IV. 95, 800 ft. abundant. Anthomyiidae'. (5) Anthomyia sulciventris Ztt., fp. 20. V. 97, 7-16. V. 98, 8-1,200 ft. (6) A. sp., fp. 18. V. 97, 19-2,000 ft. 68 . Senecio vulgaris, Linn. [Lit. Brit. 23, 29 ; A. Bateson 151 ; N.C.E. 1 , 3 c, 11, 14, 18, 25, 33, 34.] All observers find it very neglected. Visitors. Diptera. Anthomyiidae'. (1) Anthomyia sp., fp. 17-19. IX. 95, 800 ft. 69 . Senecio aquaticus, Huds. [Lit. Brit. 23 ; N.C.E. 8 .] Not so abundant as Senecio Jacohaea , and very much less visited. Visitors. Hymenoptera. Aculeata: Apidae'. (1) Bombus terres- tris L., sh. 14. IX. 95. Diptera. Syrphidae'. (2) Eristalis pertinax Scop., 14. IX. 95. Empidae'. (3) Empis tessellata F., sh. 14. IX. 95. Tachinidae : (4) Siphona geniculata Deg., sh. 14. IX. 95. Muscidae'. (5) Lucilia cornicina F., sh. 1. VII. 95. Anthomyiidae'. (6) Hyetodesia incana W., sh. 2. VII. 95; 14. IX. 95; 6. VII. 96. (7) H. variabilis Fin., sh. 1. VII. 95. (8) Anthomyia sp., 13. IX. 95. All at 7-800 ft. Insects- in Great Britain. 325 70 . Senecio Jacobaea, Linn. [Lit. Brit. 23, 34, 39 ; N.C.E. 1, 3 c, 11, 14, 16, 18, 34, 40 ; De Vries 2460 ; Alps 34 ; Pyren. 17.] A very conspicuous flower in autumn at low levels, where it attracts the drones of the common Bombi, moths, flies of all sorts and beetles; except the Bombi much in proportion to the then existing prevalence of the various classes ; but the Bombi it attracts in less degree. Visitors. Lepidoptera. Rhopalocera: (1) Polyommatus phloeas L., sh. 13-14. IX. 95, 7-800 ft. Heterocera: Noduidae : (2) Hydroecia nictitans Bkh., sh. 13-21. IX. 95, 8-900 ft. (3) Celaena haworthii Cue., sh. 16-19. IX. 95, 8-900 ft. Geometres'. (4) Psodos trepidaria Hb., sh. 11. VII. 96, 800 ft. (5) Cidaria immanata Hw., sh. 13-21. IX. 95, 7-900 ft. Crambidae : (6) Crambus sp., 14. IX. 95, 700 ft. Hymenoptera. Aculeata : Apidae : (7) Bombus terrestris L., sh. 13-24. IX. 95, 7-900 ft. (8) B. lapponicus F., sh. 16. IX. 95, 800 ft. (9) B. agrorum F., sh. 13. IX. 95, 700 ft. Vespidae : (10) Vespa norvegica F., fp. 19. IX. 95, 800 ft. Formicidae : (n) Formica fusca Latr., 16. IX. 95, 800 ft. Petiolata parasitica : Ichneumonidae : (12) 1 sp., sh. 21. IX. 95, 800 ft. Braconidae : (13, 14, and 15) 3 sp., 16-7. IX. 95, 7-800 ft. Cynipidae : (16) Eucoela fortinervis Cameron, 15. IX. 95, 800 ft. Diptera. Syrphidae : (17) Platychirus albimanus F., 16-24. IX. 95, 8-1,000 ft. (18) P. manicatus Mg., sh. 10. VII. 96, 800 ft. (19) Sericomyia borealis Fin., sh. 21. IX. 95, 800 ft. (20) Eristalis tenax L., sh. 13. IX. 95, 8-900 ft. (21) E. pertinax Scop., sh. and fp. 14-24. IX. 95, 8-900 ft. (22) E. rupium F., sh. 22. VII. 95, 800 ft. (23) E. arbustorum L., sh. and fp. 15. VII. 95 ; 13-22. IX. 95, 7-800 ft. (24) Helophilus pendulus L., 21. IX. 95, 800 ft. Empidae: (25) Empis tessellata F., 13-6. IX. 95, 7-800 ft. (26) E. punctata Mg., sh. 22. VII. 95, 800 ft. (27) E. albipennis Mg., 2i. IX. 95, 800 ft. (28) Rhamphomyia spinipes Fin., 14. IX. 95, 800 ft. Mycetophilidae : (29) Sciara sp., 16-22. IX. 95, 800 ft. Bibionidae : (30) Bibio pomonae F., fp. 13-22. IX. 95, 7-900 ft. Chironomidae : (31) Ceratopogon leucopeza Mg., 19-20. IX. 95, 800 ft. Tachinidae : (32) Siphona geniculata Deg., sh. 14-22. IX. 95, 800 ft. Sarcophagidae : (33) Cynomyia mortuorum L., 16-24. IX. 95, 9-1,000 ft. Musddae : (34) Lucilia cornicina F., 14-24. IX. 95 ; 10. VII. 96, 8-1,300 ft. (35) Calliphora vomitoria L., ? sh. 22. VII. 95, 800 ft. (36) C. erythrocephala Mg., sh. 4-22. IX. 95, 8-1,000 ft. 326 Willis and Burkill. — Flowers and (37) C. sepulchralis Mg., 17. VII. 95, 800 ft. and? 14. IX. 95, 900 ft. (38) Pollenia rudis F., sh. and fp. 15-22. VII. 95; 14-24. IX. 95, 8-1,300 ft. (39) P. vespillo F., 19. IX. 95, 800 ft. (40) Mesembryna meridiana L., 21. IX. 95, 800 ft. (41) Cyrtoneura caesia Mg., sh. and fp. 16-22. IX. 95, 8-900 ft. Anthomyiidae : (42) Hyetodesia incana W., sh. and fp. 14-24. IX. 95, 8-1,000 ft. (43) Drymia hamata Fin., fp. 14-19. IX. 95, 8-900 ft. (44) Trichophthicus sp., 16. IX. 95, 800 ft. (45, 46, and 47) Anthomyia 3 spp., sh. and fp. 13-24. IX. 95, 7-1,000 ft. Cordyluridae\ (48) Scatophaga stercoraria L., fp. 16-21. IX. 95, 7-900 ft. (49) Another sp., fp. 16. IX. 95, 800 ft. Sepsidae : (50) Sepsis cynipsea L., 10. VII. 96, 800 ft. Phoridae\ (51) Phora sp., 21. IX. 95, 800 ft. Coleoptera : (52) Meligethes viridescens F., sh. and fp. 27. VII. 95; 14-24. IX. 95, 7-1,000 ft. (53) M. aeneus F., sh. and fp. 14. IX. 95, 800 ft. (54) Brachypterus urticae F., sh. 22. IX. 95, 800 ft. (55) Homalota sp., 16. IX. 95, 800 ft. Hemiptera: (56) Anthocoris nemorum L., sh. 1 6. IX. 95, 800 ft. Thysanoptera. (57) Thrips sp., sh. 14-17. IX. 95 , 7-800 ft. Araneida: (58) Oligolophus morio Fabr., 24. IX. 95, 1,000 ft. B' § 6. Yellow-flowered Ligulate Compositae. 71. Leontodon autumnalis, Linn. [Lit. Brit . 23 , 39 ; N.C.E. 1 , 3 c, 9 , 11, 14 , 14 a, 15 , 18 , 25 , 30 , 31 , 32 , 33 , 40 ; De Vries 2460 ; Arct. 34 , 36 ; Alps 34 ; Pyren . 17 .] This plant ascends (in its var. pratense ) to considerable elevations, and is one of the most conspicuous of autumn flowers on the moors. Self-fertilization is produced in the way usual in the Compositae by the rolling back of the stigma as the flower ages. Nine-tenths of its individual visitors are short-tongued flies. Visitors of constancy hardly exist, but the circle is wide. Visitors. Lepidoptera. Heterocera: Pyralidae\ (1) Pyrausta? alpinalis Schiff., 4. VII. 95, 2,500 ft. Hymenoptera. Aculeata: Apidae : (2) Bombus terrestris L., sh. 24. IX. 95, 1,200 ft. (3) An- drena coitana Kirby, sh. 5. VII. 95, 800 ft, (4) A. analis Panz., sh. 22. VII. 95, 1,000 ft. Myrmicidae\ (5) Myrmica rubra L., ? fp. 21. IX. 95, 900 ft. Petiolata parasitica: (6) 1 sp., sh. 26. VI. 95, 900 ft. (7) a second sp., 17. IX. 95, 800 ft. Sessiliventres : Tenthredinidae : Insects in Great Britain . 327 (8) Allantus arcuatus Forst., 17. VII. 95, 800 ft. Diptera. Syrphidae : (9) Melanostoma mellinum L., 13. IX. 95, 700 ft. (10) Platychirus manicatus Mg., fp. 30. VI-20. VII. 95, 800 ft. (xi) Syrphus albo- striatus Fin., fp. 20. VII. 95, 800 ft. (12) S. balteatus Deg., fp. 13-24. IX. 95, 7-1,000 ft. (13) S. ? hunger Mg., fp. 14. IX. 95, 800 ft. (14) Eristalis pertinax Scop., sh. 13-24. IX. 95, 7-1,000 ft. Empidae'. (15) Empis punctata Mg., sh. 20. VII. 95, 800 ft. Mycetophilidae : (16) Sciara sp., fp. 21. IX. 95, 1,600 ft. Chironomidae : (17) 1 sp., sh. 30. VI. 95, 800 ft. Tachinidae'. (18) Siphona geniculata Deg., sh. 14. IX. 95, 900 ft. Muscidae: (19) Lucilia cornicina F., sh. 24. IX. 95, 8-1,200 ft. (20) Pollenia rudis F., sh. 14-24. IX. 95, 8-1,200 ft. Anihomyiidae : (21) Hyetodesia incana W., sh. and fp. 4-20. VII. 95 ; 16-21. IX. 95, 8-1,600 ft. (22) H. sp., fp. 21. VII. 95, 800 ft. (23) H. semicinerea W., fp. 21. IX. 95, 1,100 ft. (24) Drymia hamata Fin., fp. 14-24. IX. 95, 8-1,400 ft. (25) Trichophthicus sp., sh. 30. VI. 95, 800 ft. and 2. VII. 96, 2,800 ft. (26) Hylemyia nigrescens Rnd., 3. VII. 95, 800 ft. (27, 28, and 29) Anthomyia 3 spp., sh. and fp. 13-24. IX. 95, 7-2,000 ft. Cordyluridae: (30) Scatophaga ster- coraria L., 21. IX. 95, 900 ft. Phoridae : (31) Phora sp., 20. IX. 95, 2,400 ft. Coleoptera. (32) Meligethes viridescens F., sh. and fp. freq. 26-30. VI. 95; 13-24. IX. 95, 7-1,600 ft. (33) M. aeneus F., sh. 14. IX. 95, 800 ft. 72 . Crepis paludosa, Moench. [Lit. Brit . 23; N.C.E. 3 c, 18 ; Alps 2, 9 ; Pyren . 17.] Visitors. Hymenoptera. Aculeata : Formicidae : (1) Formica fusca Latr., 20. VI. 96, 800 ft. Diptera. Syrphidae'. (2) Platychirus mani- catus Mg., ?sh. 2. VII. 95, 800 ft. Anthomyiidae\ (3) Hyetodesia incana W., sh. and fp. 1. VI. 95, 19. VI.-6. VII. 96, 8-1,700 ft. (4) Limnophora sp., sh. 2. VII. 95, 800 ft. (5) Spilogaster nigrivenis Ztt., 19. VI. 96, 1,500 ft. (6) Anthomyia sp., 14. IX. 95, 800 ft. Agromy- zidae : (7) Agromyza sp., 1. VI. 95, 800 ft. Coleoptera : (8) Meligethes viridescens F., sh. 2-6. VII. 95; 29. VI.-6. VII. 96, 8-1,700 ft. 73 . Hieracium Pilo sella, Linn. [Lit. Brit. 34 ; Marquand, 1513 ; N.C.E. 1 , 3 c, 11, 12, 14, 16, 18, 25, 30, 31, 33 ; De Vries 2460 ; Arct. 36 ; Alps 16, 44 ; Pyren. 17.] At Clova fly- visited ; in South Germany, the Netherlands and Flanders visited by mid-tongued bees and by several Syrphidae ; in 328 Willis and Bur kill. — Flowers and the Alps with a considerable list of Lepidoptera among its visitors. Lindmann saw a butterfly to be a fairly frequent visitor in Norway. Visitors . Lepidoptera. Rhopalocera: (1) Lycaena icarus Rott., sh. 28. VI. 95, 800 ft. (2) Polyommatus phloeas L., sh. 22. VI. 95, 800 ft. Hymenoptera. Petiolata parasitica: (3) 1 sp. 14. VI. 95, 700 ft. Diptera. Syrphidae : (4) 1 sp., 26. VI. 96, 1, 100 ft. Empidae : (5) Tachydromia sp., ?fp. 24. VI. 96, 800 ft. (6) Empis chioptera Fin., 26. VI. 95, 800 ft. Mycetophilidae : (7) Sciara sp., sh. 18. IX. 95, 800 ft. Dolichopodidae\ (8) Dolichopus sp., sh. 26. VI. 96, 2,200 ft. Tachinidae'. (9) Siphona geniculata Deg., 18. VI. 99, 800 ft. Muscidae : (10) Lucilia cornicina F., sh. 22. VI. 95, 800 ft. Anthomyiidae : (n) Hyetodesia incana W., 18. VI. 99, 800 ft. (12) Limnophora solitaria Ztt., 28. VI. 95, 1,800 ft. (13) Hydrotaea sp., 19. VI. 99, 800 ft. (14) Hylemyia nigrescens Rnd., 16-18. VI. 99, 800 ft. (15) Trichophthicus sp., 28. VI.-4. VII. 95, 1,800 ft. (16) Anthomyia sulciventris Ztt., 25. VI. 96, 2,200 ft. (17 and 18) A. spp., sh. and fp. 14. VI.-5. VII. 95; 18-24. IN. 95; 16. VI.-10. VII. 96, 7-2,300 ft. Coleoptera : (19) Meligethes viridescens F., sh. and fp. 26. VI. 96 ; 19. VI. 99, 8-1,800 ft. (20) Brachypterus sp. ?, 26. VI. 95, 800 ft. Thysanoptera : (21) Thrips sp., 26. VI. 96, 1,800 ft. 74. Hieracium (Archi-Hieracia) spp. [Lit. Brit . 23 ; N.C.E. 1 , 3 c, 11 , 16 , 18 , 33 , 34 , 35 , 40 ; De Vries 2460 ; Loew 1358 ; Arct. 36 ; Alps 2 , 34 ; Pyren. 17 .] By the kindness of Mr. F. J. Hanbury and the Rev. E. F. Linton, who examined our specimens of Hieracia, we are able to give names to a number of forms. The Clova mountains are very rich in these, and some of them we have studied. The following notes give our observations ; we have found it impossible to do otherwise than lump the forms together in enumerating the insect visits. Recognizing in the many forms of Hieracia incipient species, we find our chief interest in noting any characters which would promote segregation of the group by preventing indiscriminate hybridisation or crossing. A tendency to flower early or late, a separation in habitat, or a more complete self-pollination than is usual Insects in Great Britain, 329 ought severally to help to isolate forms in which these charac- ters occur. Species : 1. H. alpinum, Linn. Flowers of (a) H. eximium , Backh., were carefully observed. On the second and third days after the expansion of the head, the pollen was swept out in the outer florets; on the fourth day the stigmas of these outer florets separated. On the sixth day all the florets were open, and the stigmas of the outermost so recurved as to be self-pollinated. Thus apparently this form secures self- fertilization in the absence of insect visitors. ( b ) H. holoseri- ceum , Backh., growing with the last, is perhaps not self- pollinated to the same extent. ( c ) H. alpimim , the segregate, (d) H. calenduliflorum , Backh., and (e) H. gracilentum , Backh., are other Clova forms. Species : 2. H. nigrescens, (/) H. Marshallii , Linton, (g) H. senescens, Backh., ( h ) H. chrysanthum , Backh., and (i) H. lingulatum , Backh., are all forms which we have found at Clova. II. chrysanthum is rather distinct in its orange- yellow heads, but all the species of insects, seen to visit it, were seen on other species, so that so far as we know the colour causes no selection. The stigmas become slightly revolute, and this brings about self-pollination. Species : 3. H. anglicum, Fries, (j) H. angticum , segregate, (£) H. iricum , Fries, (/) II. ctovense , Linton, (m) H. cerinthi - forme , Backh., were obtained. Also (n) H. callistophyllum, F. J. Hanb., has been gathered at Clova. (F. J. Hanbury, Brit. Hierac., pp. 65, 66.) On the crags at Loch Brandy grow together H. eximium and II ctovense . The former begins to flower before the latter, but their flowering-periods overlap. Heads of H. ctovense were kept in a room side by side with H. eximium , already described. For five days the behaviour of H. ctovense was just like that of H. eximium , but on the sixth day when the last of the florets of It. eximium were open, there were still some florets of H. ctovense to open, and further the stigma of H. ctovense never recurved as tightly as that of H. eximium , and consequently self-pollination would 330 Willis and Bur kill. — Flowers and appear to be less inevitable. Perhaps of these two associates the earlier flowering of the one, and the less period of time when cross-fertilization is possible, may prevent in a measure the crossing which we believe extremely likely to occur. There are then causes which -would help incipient species to become isolated. We have seen more insects on H. clovense than on H. eximium , but they are of the same or similar species. SPECIES : 4. H. murorum, Linn. ( 0 ) H. Schmidtii , Tausch, (/) H. Leyi, F. J. Hanb., (q) H. lasiophyllum , Koch, and (r) H. argenteum , Fries, were obtained. The second seems very common in some spots. It grows at lower levels than H. eximium , H. chrysauthum , and H . holosericeum for the most part, rarely exceeding 2,250 feet, and where mixed with H. eximium flowering like H. clovense^ a little later than it. The stigma becomes tightly recurved when old. We have also gathered (.?) H. pictorum , Linton, ( t ) H. murorum , segre- gate, (u) H. aggregation , Backh., and ( v ) IP. rivale , F. J. Hanb. Species : 5. H. sylvaticum. (w) H. vulgatum , Fries, (x) H. euprepes , F. J. Hanb., (y) H. angustatum , Lindeb., and (z) H. diaphanoides , Lindeb., have been obtained at Clova (Linton, in Journ. Bot. 1890, p. 168; Druce, Ann. Scot. Nat. Hist. 1896, p. 126 ; F. J. Hanb., Journ. Bot. 1893, p. 133). The stigma of these becomes ultimately tightly recurved. With the exception of H. pictorum those we have seen all grow intermixed. Other sub-species or varieties of Hieracia have been found at Clova, bringing up the total to thirty-one forms. For their names see our paper in the Trans. Edinb. Bot. Soc. There is a sort of stratification about the Hieracia. The sub-species of H. alpina grow at the highest levels, next in descending the hills we come to the sub-species H. Leyl H. clovense , H. argenteum , and similar forms. Lowest come the more richly branched forms, such as H. anglicum. One form, H. vulgatum, we have found at all heights, from 700- 2,900 feet. The others have a much less extensive range. The insects which visit the Hieracia are none of them wide- Insects in Great Britain. 33i flying, and there is every probability that a floret if crossed will be fertilized from a very similar plant. This is another cause helping to allow the segregation of the group. Visitors. Lepidoptera. Heterocera : Pyralidae : (1) Pyrausta alpi- nalis Schiff., sh. (to b, h, j, p) 1-6. VII. 96, 25-2,700 ft. Hymeno- ptera. Aculeata : Myrmicidae : (2) Myrmica rubra L., (to w) biting flowers, 18. VI. 96, 1,400 ft. Petiolata parasitica: Cynipidae : (3) Cynips sp., (to w) 16. VI. 96, 700 ft. Diptera. Syrphidae : (4) Melanostoma mellinum L., (to w) fp. 16. IX. 95, 800 ft. (5) Platychirus manicatus Mg., (to j, r,w) 1-6. VI. 96, 17-2,700 ft. Empidae : (6) Empis lucida Ztt., (to w) 4. VII. 95, 1,800 ft. (7) E. sp., (to w) 29. VI. 96, 800 ft. (8) E. aestiva Lw., (to w) 29. VI. 96, 800 ft. Myceto- philidae\ (9) Sciara sp., (to w) sh. 30. VI. 96, 2,100 ft. Bibionidae\ (10) Dilophus albipennis Mg., (to w) sh. 26. VI. 96, 1,200 ft. Tachi- nidae : (n) Siphona geniculata Deg., (to t, w) 18-25. VI. 96, 7-800 ft. Muscidae: (12) Lucilia cornicina F., (to w) sh. 24. IX. 96, 1,000 ft. Anthomyiidae : (13) Hyetodesia incana W., (to b, h, j, 1, p, r, t, w) sh. and fp. freq. 23. VI.-4. VII. 95, 18. VI.-6. VII. 96, 8-2,600 ft. (14) H. basalis Ztt., (to w) sh. 4. VII. 95, 1,200 ft. (15) Drymia hamata Fin., (to a, b, c, h, j, 1, t) sh. and fp. 26. VI.-2. VII. 96, 17-2,700 ft. (16) Spilogaster nigrivenis Ztt., (to w) 19. VI. 96, 1,500 ft. (17) Trichophthicus hirsutulus Ztt., (to h, j, p) 6. VII. 96, 17-2,000 ft. (18) T. sp., (to a, 1, p, w) fp. 20. VI.-6. VII. 96, 18-2,500 ft., 16. IX. 95, 8-900 ft. (19) Anthomyia sulciventris Ztt., (to 1) 25. VI. 96, 2,000 ft.. (20 and 21) A. sp., (to b, w) sh. 13. VII. 95, 19. IX. 95, 27. VI. 96, 22-2,400 ft. [and also Anthomyiidae to a, g, h, j, 1,- p, r, w, VI. and VII. 96, 8-2,500 ft.]. Coleoptera. (22) Meligethes viri- descens F., (to p) fp. 26. VI. 96, 2,100 ft. (23) Anthophagus alpinus Payk., (to a) ? fp. 10. VII. 96, 2,500 ft. Hemiptera. (24) Aphis sp., (to k) 22. VI. 96, 2,300 ft. 75 . Lapsana communis, Linn. [Lit. Brit. 23; N.C.E. 1, 3 c, 11, 14, 18 ; Warnstorf 2507 ; Pyren. 17.] Nowhere, as far as present records go, well visited. Visitors. Coleoptera. (1) Meligethes viridescens F., sh. 2. VII. 95, 800 ft., nine individuals. 76 . Hypochoeris radicata, Linn. [Lit. Brit. 23 ; N.C-E. I, 3 c, 12 , 14, 14 a, 16, 18, 25, 34,40; Alps 2 ; Pyren. 17.] 332 Willis and BurkilL — Flowers and The Clova visitors to this species are a little more specialized than those to Leontodon autumn ale, the cause being in its earlier flowering. Andrena showed some measure of constancy, as also did Eristalis. The young flowers close at night and remain closed by day during rain. Mid-tongued bees are the most numerous in the list of North Central Europe and mid- tongued flies stand second. Visitors. Lepidoptera. Rhopalocera: (i) Vanessa urticae L., sh. 2. VII. 95, 8oo ft. (2) Lycaena icarus Rott., sh. 25. VI. 96, 800 ft. Heterocera : Eriocephalidae : (3) Eriocephala calthella L., fp. 5-6. VII. 95, 8-1,400 ft. Hymenoptera. Aculeata: Apidae : (4) Bombus ?ter- restris L., sh. 10. VII. 95, 800 ft. once. (5) Andrena coitana Kirby, 5-8. VII. 95, 7-800 ft. (6) A. analis Panz., sh. 18. VI.-n. VII. 96, 8-1,100 ft. Formicidae\ (7) Formica fusca Latr., 18. VI. 96, 800 ft. Sessiliventres : Tenthredinidae\ (8) Allantus arcuatus Forst., 26. VI.-5. VII. 95, 7-800 ft. fairly freq. Petiolata parasitica : Ichneumonidae : (9) 1 sp., 26. VI.-6. VII. 95, 26-27. VI. 96, 8-1,000 ft. Diptera. Syrphidae\ (10) Chilosia fraterna Mg., 22. VI.-3. VII. 95, 25. VI. 96, 800 ft. (n) C. antiqua Mg., sh. 5. VII. 95, 800 ft. (12) Platychirus manicatus Mg., sh. 25. VI.-6. VII. 95, 18-25. VI. 96, 800 ft. (13) Syrphus ribesii L., fp. 5. VI. 95, 6. VII. 96, 800 ft. (14) S. ? gros- sulariae Mg., 1. VII. 95, 800 ft. (15) Volucella bombylans L., fp. 2-8. VII. 95, 800 ft. (16) Sericomyia borealis Fin., sh. 26. VI.-i. VII. 96, 800 ft. (17) Eristalis pertinax Scop., 20. VI. 95, 25. VI.-10. VII. 96, 800 ft. (18) E. rupium F., 5. VII. 95, 19. VI. 96, 800 ft. (19) E. arbustorum L., 5. VI. 95, 800 ft. Empidae\ (20) Empis aestiva Lw., sh. 5. VII. 95, 800 ft. (21) Rhamphomyia nigripes F., 2. VII. 95, 800 ft. (22) Tachydromia sp., sh. 5. VII. 95, 800 ft. Tabanidae'. (23) Atheryx ibis F., sh. 1. VII. 95, 800 ft. Tachinidae'. (24) Siphona geniculata Deg., sh. 17. VI.-5. VII. 95, 800 ft. (25) Tachinid sp., sh. 6. VII. 95, 1,400 ft. Muscidae : (26) Calliphora vomitoria L., sh. 2. VII. 95, 800 ft. (27) C. erythrocephala Mg., 25- 27. VI. 96, 800 ft. Anthomyiidae : (28) Hyetodesia incana W., sh. and fp. 17. VI.-6. VII. 95, 18. VI.-6. VII. 96, 16-19. VI. 99, 800 ft. (29) Drymia hamata Fin., 29. VI.-2. VII. 95, 2. VII. 96, 800 ft. (30) Trichophthicus hirsutulus Ztt., 10. VII. 96, 800 ft. (31) T. sp., sh. 28. VI.-2. VII. 95, 16. IX. 95, 9-1,500 ft. (32) Hylemyia nigrescens Rnd., 22. VI.-3. VII. 95, 800 ft. (33) Anthomyia sulciventris Ztt., Insects in Great Britain. 333 sh. 22. VI. 95, 8oo ft. (34) A. pudica Rnd., 22. VI. 95, 800 ft. (35 and 36) A. spp., sh. and fp. 14. VI. -5. VII. 95, 17. IX. 95, 16. VI.-11. VII. 96, 7-1,300 ft. (37) Caricea tigrina F., 16. VI. 95, 800 ft. (38) Coenosia sp., 16. VI.-4. VII. 95, 800 ft. Coleoptera. (39) Meligethes aeneus F., 16. VI. 95, 800 ft. (40) M. viridescens F., sh. and fp. 25. VI.-5. VII. 95, 16-17. IX. 95, 16. VI.-8. VII. 96, 8-1,600 ft. (41) Phyllobius pomonae 01 ., ? sh. 1. VII. 95, 800 ft. Thysanoptera. (42) Thrips sp., 5. VI. 95, 800 ft. Araneida. (43) Xysticus sp., lying in wait, 22. VI. 95, 10. VII. 96, 8-900 ft. 77 . Taraxacum officinale, Web. [Lit. Brit. 23, 29, 34 ; N.C.E. 1,3c, 11, 14, 16, 18, 25,31,34,35,40; DeVries 2460; Warnstorf 2507 ; Medit. 34 ; Arct. 34, 36 ; Alps 2 , 9, 16, 34 ; Pyren. 17.] All the season visited by abundant Anthomyids. In early spring Apis shows a measure of constancy but neglects the flower afterwards ; a few butterflies visit the flowers in spring not irregularly. Lists of visitors for North Central Europe are in the most marked contrast ; in South Germany, on the Frisian coast, in the Netherlands and in Flanders long and mid-tongued bees are many and mid- tongued flies come next to them. In the Alps Lepidoptera are most numerous, but the bees are hardly less in numbers than the flies. Lindmann, however, observed the flower to be visited by many small or moderately small flies in Norway. Visitors. Lepidoptera. Rhopalocera: (1) Argynnis selene Schiff., sh. 14. VI. 99, 1,400 ft. (2) Vanessa urticae L., sh. not infreq. 24. V. 96, 19-27. V. 97, 7. V. 98, 6-900 ft. (3) Pieris napi L., sh. 22-23. V. 97, 1 1-1 6. VI. 99, 6-800 ft. (4) P. ? rapae L., sh. 20. V. 97, 800 ft. (5) Polyommatus phloeas L., sh. 24. V. 96, 800 ft. Heterocera: Geometridae : (6) 1 sp., 11. VI. 99, 800 ft. (7) a second species, 13-14. VI. 99, 900 ft. Pyralidae\ (8) Pyrausta alpinalis Schiff., sh. 4. VII. 95, 2,700 ft. and 1. VII. 96, 1,800 ft. Tineidae\ (9) 1 sp., sh. 11. VI. 99, 800 ft. Hymenoptera. Aculeata: Apidae : (10) Apis mellifica L., sh. and cp. 20-27. V. 97, 7-15. V. 98, 6-800 ft. (11) Bombus lapponicus F., sh. 23. V. 97, 15. V. 98, 800 ft. (12) Andrena analis Panz., sh. 25. V. 96, 800 ft. Petiolata parasitica : Ichneumonidae: (13) 1 sp., sh. 25. V. 96, 800 ft. Prodotrupidae\ (14) 1 sp., 11. VI. 99, 800 ft. Diptera: Syrphidae\ (15) Platychirus albimanus F., 17- 334 Willis and Bur kill. — Flowers and 19. IX. 95, 800 ft. (16) P. manicatus Mg., sh. and fp. 19. VI. 95, 21. V. 96, 10-11. VI. 99, 7—800 ft. (17) P. discimanus Loew, ? fp. 15. V. 98, 800 ft. (18) Chilosia fraterna Mg., sh. 11-16. VI. 99, 800 ft. Empidae\ (19) Empis tessellata F., sh. 21. V. 96, 16. VI. 99, 800 ft. (20) Empis bilineata Lw., sh. 27. V. 97, 14. VI. 99, 8-900 ft. Mycetophilidae\ (21) Sciara sp., 11. VII. 96, 800 ft. Bibionidae'. (22) Scatopse sp., n. VII. 96, 800 ft. Chironomidae\ (23) Tanytarsus sp., 11. V. 98, 1,000 ft. Tachinidae\ (24) Siphona geniculata Deg., sh. 21. V. 98, 10. VI. 99, 7-800 ft. Muscidae : (25) Lucilia cornicina F., sh. and fp. 27. V. 97, 7-13. V. 98, 10. VI. 99, 6-800 ft. (26) Pollenia vespillo F., sh. 22-27. V. 97, 10. VI. 99, 6-800 ft. Anthomyiidae\ (27) Hyetodesia incana W., sh. 20. VI.-4. VII. 95, 1. VII. 96, 8-2,700 ft. (28) Trichophthicus sp., sh. 24. VI.-4. VII. 95, 1. VII. 96, 16-2,700 ft. (29) Anthomyia radicum L., 11. VI. 99, 800 ft. (30) A. sulciventris Ztt, sh. and fp. very ab. 28. VI. 95, 18-27. V. 97, 12. V. 98, 7-800 ft. and once at 2,000 ft. (31, 32, and 33) A. 3 spp., fp. 19. VI.-4. VII. 95, 19. IX. 95, 21-22. V. 96, 6. VI. 96, 19-24. V. 97, 16. V. 98, 10-16. VI. 99, 6-2,600 ft. Cordyluridae\ (34) Scato- phaga stercoraria L., sh. and fp. 27. V. 97, 12-13. V. 98, 800 ft. Phoridae\ (35) Phora rufipes Mg., sh. 22. V. 96, 1,100 ft. Coleo- ptera. (36) Meligethes viridescens F., sh. and fp. 17-21. IX. 95, 10. VI. 99, 7-800 ft. B' § 7. Eyed Compositae. 78 . Beilis perennis, Linn. [Lit. Brit. 23, 29 ; N.C.E. 1, 3c, 11 , 14,14a, 16, 18, 25, 30, 31,34; De Vries 2460; Warn- storf 2507 ; Medit. 34 ; Alps 2, 9 ; Pyren. 17.] Visited in spring and less so in summer by great numbers of short - tongued flies, chiefly Anthomyiids. Visitors. Lepidoptera. Rhopalocera: (1) Pieris rapae L., sh. 24. V. 97, 800 ft. (2) P. napi L., sh. 11-13. VI. 99, 800 ft. (3) Lycaena icarus Rott., sh. 1. VII. 95, 800 ft. (4) Coenonympha pam- philus L., sh. 10. VII. 96, 2,500 ft. Heterocera: (5) 1 Microlepido- pteron, 25. VII. 96, 800 ft. Hymenoptera. Aculeata: Apidae\ (6) Apis mellifica L., 15. IV. 95, 13. V. 98, 800 ft. (7) Andrena sp., sh. 20. V. 97, 900 ft. Myrmicidae\ (8) Myrmica rubra L., 23. VI. 95, 900 ft. Petiolata parasitica: (9) 1 sp., 27. V. 97, 700 ft. Diptera. Syrphidae : (10) Melanostoma ? quadrimaculatum Verrall, Insects in Great Bintain . 335 sh. 1 6. VI. 95, 8co ft. (ii) Platychirus discimanus Loew, 27. V. 97, 16. V. 98, 800 ft. (12) P. manicatus Mg., 10. VI. 99, 700 ft. (13) P. albimanus F., 21. IX. 95, 800 ft. (14) Syrphus vitripennis Mg., 1 o— 1 1 . VI. 99, 7-1,200 ft. (15) S. sp., 10. VI. 95, 2,300 ft. (16) Eristalis arbustorum L., sh. 22. VI. 99, 800 ft. (17) Syritta pipiens L., 19. VI. 99, 900 ft. Empidae\ (18) Empis tessellata F., 10. VII. 96, 900 ft. (19) E. bilineata Lw., sh. 27. V. 97, 700 ft. (20) E. ? lucida Ztt., 23. V. 97, 900 ft. (21) E. ? vernalis Mg., sh. 11-12. VI. 99, 11-2,200 ft. (22) E. opaca F., sh. 13. VI. 99, 700 ft. (23) Hilara matrona Hal., sh. 17. VII. 97, 800 ft. Mycetophilidae : (24) Sciara sp., 14-24. IX. 95, 10-1,600 ft. Dolichopodidae\ (25) Hercostomus nigripennis Fin., 1. VII. 95, 800 ft. Tachinidae\ (26) Siphona geniculata Deg., sh. 24. VI. 95, 10. VI. 99, 7-1,400 ft. Muscidae : (27) Lucilia cornicina F., sh. 16. IV. 95, 18-20. V. 97, 7-8. V. 98, 10. VI. 99, 7-800 ft. (28) Pollenia vespillo F., 7. V. 98, 1,700 ft. (29) P. rudis F., 15. IV. 95, 30. VI. 95, 800 ft. Antho- myiidae\ (30) Hyetodesia incana W., fp. 20. VI.— 4. VII. 95, 24. IX. 95, 18. VI. 96, 8-1,000 ft. (31) Spilogaster quadrum F., 20. VI. 95, 800 ft. (32) Hylemyia nigrescens Rnd., 11. VI. 99, 1,200 ft. (33) Trichophthicus sp., 14-16. IX. 95, 13-1,600 ft. (34) Anthomyia sulciventris Ztt., fp. 18-27. V. 97, 7-12. V. 98, 5-800 ft. very ab. ( 35 . 36, and 37) A. 3 spp., sh. and fp. 22. VI.-5. VII. 95, 19-24. IX. 95, 21-22. V. 96, 18. VI.-11. VII. 96, 18-24. V. 97, 10-15. VI. 99, 6-2,300 ft. Cordyluridae : (38) Scatophaga stercoraria L., 21. IX. 95, 19. VI. 96, 27. V. 97, 12-14. V. 98, 8-1,400 ft. Coleoptera. (39) Meligethes viridescens F., fp. 24. IX. 95, 10. VI. 99, 7-1,000 ft. Hemi- ptera. (40) 1 sp., 4. VII. 95, 800 ft. Thysanoptera. (41) Thrips sp., sh. 26. VI. 96, 1,800 ft. 79. Chrysanthemum Leucanthemum, Linn. [Lit. Brit. 23 ; N.C.E. 1 , 3 c, 11, 14 , 16 , 18 , 30 , 31 , 34 , 40 ; Warnstorf 2507 ; Alps 2 , 16 , 34 ; Pyren. 17 .] Large heads at Clova were found to attain 72 mm. in diameter, the disk being 18 mm. across. Visitors. Lepidoptera. Heterocera : Tortricidae : (1) Tortrix sp., sh. 2. VII. 95. Diptera. Empidae : (2) Empis sp., sh. 22. VII. 95. (3) E. bilineata Lw., 2. VII. 95. Tachinidae : (4) Siphona geniculata Deg., 21. VI. 95. Anthomyiidae : (5) Hyetodesia incana W., 29. VI. 96. (6) Trichophthicus sp., 30. VI. 95, 16. IX. 95. 336 Willis and Burkill. — Flowers and Coleoptera. (7) Meligethes viridescens F., fp. 2. VII. 95, 16. IX. 95. Thysanoptera. (8) Thrips sp., sh. 24. VI. 96. All at 8-900 ft. 80. Matricaria inodora, Linn. [Lit. Brit. 23 , 39 ; N.C.E. 1 , 3 c, 11 , 14 , 18 , 31 .] Visitors. Hymenoptera. Aculeata: Apidae : (1) Apis mellifica L., sh. 22. VII. 95. Diptera. Syrphidae : (2) Platychirus albimanus F., ?sh. 22. IX. 95. (3) Syrphus vitripennis Mg., 15. VII. 95. (4) Ascia podagrica F., sh. 17. VII. 95. (5) Eristalis arbustorum L., sh. 15. VII. 95. (6) E. rupium F., sh. 22. VII. 95. (7) Syritta pipiens L., sh. and?fp. 15-19. VII. 95, 22. IX. 95. Empidae'. (8) Rhamphomyia sp., 5. VII. 96. Tachinidae\ (9) Siphona geniculata Deg., 24. VI. 96. Muscidae : (10) Lucilia sericata Mg., fp. 15. VI. 95. (11) L. cornicina F., sh. 7. VII. 95, 22. IX. 95. (12) Pollenia rudis F., sh. and fp. 15. VII. 95, 22-23. IX. 95. Anthomyiidae : (13) Anthomyia sp., 17. IX. 95, 22. VI. 96. Cordyluridae : (14) Scato- phaga stercoraria L., 22. IX. 95. Sepsidae: (15) Sepsis cynipsea L., 17. IX. 95, 22. VI. 96. Coleoptera. (16) Meligethes viridescens F., fp. 17-22. IX. 95. (17) Amara bifrons Gyll., ? fp. 3. VII. 95. Orthoptera. (18) Forficula sp., devouring the ray-florets, 3. VII. 95. Thysanoptera. (19) Thrips sp., 17. IX. 96. All at 800 ft. B' § 8. White Compositae. 81. Antennaria dioica, R. Br. [Lit. N.C.E. 14 , 18 , 25 , 33 ; Arct. 38 ; Alps 2 , 9 ; Pyren. 17 .] Flowers rarely rose pink. Visitors. Lepidoptera. Heterocera : Geometridae : (1) Melanippe sp., sh. 25. VI. 96, 2,200 ft. (2) Cidaria immanata Hw., 22. VI. 96, 2,300 ft. Hymenoptera. Aculeata: Vespidae : (3) Odynerus tri- marginatus Zett., ? sh. 15. VI. 99, 800 ft. Diptera. Empidae : (4) Empis livida L., sh. 22. VI. 96, 2,400 ft. Bibionidae'. (5) Dilophus albipennis Mg., 15. VI. 95, 900 ft. Chironomidae : (6) 1 sp., 6. VI. 95, 2,300 ft. Muscidae : (7) 1 sp., 16. VI. 99, 1,500 ft. Anthomy- iidae : (8) Drymia hamata Fin., 26. VI. 96, 2,400 ft. (9) Trichoph- thicus hirsutulus Ztt., fp. 6. VI. 96, 2,100 ft. (10) Coenosia sp., 21. VI. 95, 27. VI. 96, 20-2,200 ft. Coleoptera. (n) Meligethes viri- descens F., ? fp. 1. VII. 96, 1,700 ft. (12) Sericosomus brunneus F., 16. VI. 99, 1,500 ft. Insects in Great Britain. 337 82. Achillea Ptarmica, Linn. [Lit. Brit. 23; N.C.E. 1, 3 c, 11, 14, 14 a, 18 ; Loew 1358.] Visitors. Diptera. Empidae : (1) Empis tessellata F., sh. 14. IX. 95, 800 ft. Anthomyiidae : (2) Drymia hamata Fin., 16. IX. 95, 800 ft. (3) Anthomyia sp., 15. IX. 95, 800 ft. Cordyluridae : (4) Scatophaga sp., sh. 20. VII. 95, 800 ft. 83. Achillea Millefolium, Linn. [Lit. Brit. 23, 34, 39 ; N.C.E. 1, 3 c, 8, 11, 12, 14, 14a, 16, 18, 25, 31, 33, 34, 40; Arct. 36 ; Alps 2, 9 ; Pyren . 17.] Flowers sometimes rose- pink. Muller in his lists unites this species and A. Ptarmica together. Visitors. Lepidoptera. Heterocera : Noctuidae : (1) Hydroecia nictitans Bkh., 14-16. IX. 95, 800 ft. (2) Dianthecia cucubali Fuessl., sh. 2. VII. 95, 800 ft. Tortricidae : (3) Tortrix sp., 2. VII. 95, 800 ft. Tineidae : (4) Glyphipteryx fuscoviridella Haw., sh. 1-2. VII. 95, 900 ft. Hymenoptera. Aculeata : Apidae : (5) Bombus ter- restris L., sh. 25. VI. 95, 13-14. IX. 95, 7-800 ft. (6) Andrena analis Panz., sh. 6. VII. 95, 800 ft. (7) Halictus subfasciatus Nyl, 14. IX. 9 5, 800 ft. Vespidae : (8) Vespa norvegica F., 13. IX. 95, 700 ft. Sessiliventres : Tenthredinidae : (9) Allantus arcuatus Forst., sh. 26. VI.-22. VII. 95, 2. VII. 96, 800 ft. Petiolata parasitica: Ichneumonidae : (10) Limneria crassicornis, 16. IX. 95, 800 ft. (1 1) Hemiteles ? tenebriosus Grav., 2. VII. 95, 800 ft. (12, 13, and 14) three other spp., 1. VII. 95, 800 ft. Diptera. Syrphidae : (15) Platychirus manicatus Mg., sh. 26. VI. -3. VII. 95, 10. VII. 96, 800 ft. (16) P. albimanus F., fp. 18. VII. 95, 800 ft. (17) Syrphus ? vitripennis Mg., 15. VII. 95, 3. VII. 96, 800 ft. (18) Syrphus sp., 13-14. IX. 95, 7-800 ft. (19) Ascia podagrica F., 17. IX. 95, 800 ft. (20) Eristalis pertinax Scop., 13-18. IX. 95, 7-800 ft. (21) E. arbus- torum L., fp. 6. VII. 95, 800 ft. (22) Heliophilus pendulus L., sh. 21-22. IX. 95, 8-900 ft. (23) Syritta pipiens L., 30. VI.-i. VII. 95, 800 ft. Empidae: (24) Empis tessellata F., sh. 15-23. VII. 95, 13-16. IX. 95, 2-1 1. VII. 96, 7-900 ft. (25) E. punctata Mg., sh. 19. VI- 17. VII. 95, 800 ft. (26) E. bilineata Lw., 28. VI.-5. VII. 95, 800 ft. (27) E. grisea Fin., 16. IX. 95, 900 ft. (28) Pachymeria pal- paris Egg., 16. IX. 95, 900 ft. (29) Rhamphomyia spinipes L., 30. VI. 95, 16. IX. 95, 8-900 ft. (30) Hilara martrona Hal., sh. 17. VII. 95. 338 Willis and Bur kill — Flowers and 800 ft. Cecidomyiidae : (31) Lestremia sp., 16. IX. 95, 800 ft. Bibio- nidae\ (32) Dilophus albipennis Mg., 28. VI. 95, 800 ft. Chiro- nomidae : (33) 1 sp., fp. 6. VII. 95, 800 ft. Tachinidae\ (34) Siphona geniculata Deg., 16-18. IX. 95, 800 ft. Sarcophagidae : (35) Cy- nomyia mortuorum L., 16. IX. 95, 800 ft. Muscidae: (36) Lucilia cornicina F., fp. 2-6. VII. 95, 13-24. IX. 95, 8-1,600 ft. (37) L. sericata Mg., sh. 20. VII. 95, 800 ft. (38) Calliphora erythrocephala Mg., sh. 5. VII. 95, 18-21. IX. 95, 800 ft. (39) C. ? vomitoria L., 22. VI. 95, 800 ft. (40) Pollenia rudis F., sh. 30. VI. -5. VII. 95, 13-24. IX. 95, 8-1,200 ft. (41) Cyrtoneura caesia Mg., 16-21. IX. 95, 800 ft. Anthomyiidae : (42) Hyetodesia incana W., sh. and fp. 26. VI. -15. VII. 95, 16-21. IX. 95, 8-1, 8co ft. (43) H. basalia Ztt., 17. VII. 95, 800 ft. (44) Hylemyia nigrescens Rnd., 2. VII. 95, 800 ft. (45) Drymia hamata Fin., sh. and fp. 6. VII. 95, 14-16. IX. 95, 800 ft. (46) Anthomyia sulciventris Ztt., fp. 1. VII. 95, 800 ft. (47, 48, and 49) A. 3 spp., sh. and fp. 23. VI.-22. VII. 95, 13-21. IX. 95, 16. VI.-11. VII. 96, 7-900 ft. (50) Trichophthicus sp., 29-30. VI. 95, 16-18. IX. 95, 8-900 ft. (51) Coenosia infantula Rnd., 2. VII. 95, 800 ft. Cordyluridae : (52) Scatophaga stercoraria L., fp. 6-20 VII. 95, 14-22. IX. 95, 7-900 ft. (53) S. maculipes Zett., 2. VII. 95, 800 ft. Opomyzidae : (54) Opomyza germinationis L., 17. IX. 95, 700 ft. Chloropidae : (55) Oscinis sp., fp. 6. VII. 95, 800 ft. Phoridae\ (56) Phora sp., 17. IX. 95, 800 ft. Coleoptera. (57) Meligethes viridescens F., sh. and fp. 14-22. IX. 95, 8-1,000 ft. (58) M. aeneus F., 21. IX. 95, 8:0 ft. (59) Brachypterus urticae F., 15. IX. 95, 800 ft. (60) Thyanis laevis Duft., ? fp. 27. VI.-i. VII. 95, 800 ft. Hemiptera. (61) Anthocoris nemorum L., sh. 21. IX. 95, 800 ft. (62) Lygus campestris Fabr., 16. IX. 95, 800 ft. A' § 9. Umbelliferae. 84. Pimpinella Saxifraga, Linn. [Lit. Brit. 23, 39 ; N. C.E. 1, 3 a, 12, 14, 16, 18, 21a, 30, 34, 40; Arct. 36; Alps 21 b, 34 ; Pyren. 17.] Visitors . Lepidoptera. Heterocera : Noduidae : (1) Miana fas- ciuncula Haw., sh. 20. VI. 95. Hymenoptera. Aculeata: Apidae : (2) Andrena analis Panz., sh. 23. VI. 95. Petiolata parasitica : Cynipidae : (3) Eucoela fortinervis Cameron, 23. IX. 95. Ichneumo - nidae\ (4 and 5) Hemiteles spp., 5-20. VII. 95, 22. IX. 95. (6) Xylo- Insects in Great Britain . 339 nomus sp., 21. IX. 95. (7, 8, 9, and 10) four other spp., 13 VII. 95, 18. IX. 95, 25. VI. 96. Braconidae : (n) 1 sp., ? sh. 17. VII. 95. Chalcididae : (12 and 13) 2 spp., 20-23. VII. 95, 13-23. IX. 95, 24. VI. 96. Sessiliventres : Tenthredinidae : (14) Allantus arcuatus Forst, 8-20. VII. 95, 29. VI.-3. VII. 96. (15) another sp., 12. VII. 95. Diptera. Syrphidae : (16) Chilosia fraterna Mg., sh. 20. VII. 95. (17) C. scutellata Fin., sh. 13. VII. 95. (18) Syrphus ribesii L., sh. 20. VII. 95. (19) S. vitripennis Mg., sh. 20. VII. 95. (20) Eristalis pertinax Scop., 18. IX. 95. Empidae : (21) Empis tessellata F., sh. 20. VII. 95. (22) E. punctata Mg., sh. 23. VII. 95. Mycetophilidae : (23) Sciara sp., 22. IX. 95. Bibionidae : (24) Bibio pomonae F., sh. 23. VII. 95, 22. IX. 95. Chironomidae : (25) 1 sp., 5. VII. 95. Ti- pulidae : (26) Pachyrrhina maculosa Mcq., sh. 17. VII. 95. Tachi- nidae : (27) Siphona geniculata Deg., 23. IX. 95. Muscidae : (28) Calliphora erythrocephala Mg., sh. 12. VII. 95. (29) Pollenia rudis F., sh. 16-21. IX. 95. Anthomyiidae : (30) Hyetodesia incana W., 10-12. VII. 95, 5. VII. 96. (31) Drymia hamata Fin., sh. 12. VII. 95 - (S 2 ) Trichophthicus sp., 16. IX. 95. (33 and 34) Anthomyia spp., 15-18. IX. 95, 24. VI. 96. (35) Azelia aterrima Mg., sh. 17. VII. 95. Cordyluridae : (36) Scatophaga stercoraria L., sh. 1-17. VII. 95, 13. IX. 95. Sciomyzidae : (37) Tetanocera elata F., sh. 23. VII. 95. Sapromyzidae : (38) Sapromyza apicalis Lw., sh. 23. VII. 95. Sepsidae : (39) Sepsis cynipsea L., sh. 5-20. VII. 35. Borbo- ridae : (40) Borborus geniculatus Mcq., 5. VII. 95. Phoridae : (41) Phora sp., sh. 23. VII. 95. Coleoptera. (42) Meligethes viridescens F., 15-23. IX. 95. All at 7-900 ft. 85. Conopodium denudatum, Koch. [Lit. Brit. 23 ; Pyren. 17.] Visitors. Hymenoptera. Aculeata: Acutilingues \ (1) Apis melli- fica L., 17. VI. 95. T erebrantia : Ichneumonidae : (2) Alomyia de- bellator Fabr., n. VI. 99. (3) Hemiteles ? tenebricosus Gravenh., sh. 22. VI. 95. (4) Hemiteles sp., sh. Chalcididae : (5) 1 sp., 18. VI. 96. Phytophaga : (6) Allantus arcuatus Forst., lounging and sh. 15-25. VI. 95. (7) Nematus fallax Lep., 21. V. 96. Diptera. Syrphi- dae'. (8) Platychirus manicatus Mg., 17. VI. 95, 16. VI. 99. (9) Syrphus vitripennis Mg.,11-16. VI. 99. Empidae : (10) Empis tessellata F., sh. 15- 16. VI. 99. (ii)E. bilineata Lw., 15-16. VI. 99. Tipulidae : (12) Tipula varipennis Mg., sh. 16. VI. 99. Muscidae : (13) 1 sp., n. VI. 99. 340 Willis and BurkilL — Flowers and Anthomyiidae : (14) Hye'odesia incana W., 17. VI. 95, ? 23. V. 96. (15) Hylemyia nigrescens Rnd., 17-30. VI. 95. (16) Anthomyia sulciventris Ztt., 18. VI. 96, 10-15. VI. 99. (17) A. radicum L., 11. VI. 99. Cordyluridae'. (18) Scatophaga stercoraria L., 17. VI. 95. Sapromyzidae '. (19) Sapromyza sp., 17. VI. 99. Hemiptera. (20) Nabis flavimarginatus D. and S., 17. VI. 95. Thysanoptera. (21) Thrips sp., 18. VI. 96, 17. VI. 99. All at 7-900 ft. 86 . Anthriscus sylvestris, Hoffm. [Lit. Brit. 29; N.C.E. 1, 3 a, 16, 18, 21 a, 25, 32, 34, 40 ; Alps 16 ; Medit. 34.] Visitors. Lepidoptera. Heterocera: Bo?nbycidae\ (1) Hepialis humuli L., sh. 23. VI. 95. Hymenoptera. Petiolata parasitica: Chalcididae : (2) 1 sp., 24. VI. 96. Sessiliventres : Tenthredinidae : (3) Dolerus elongatus Htg., 15-21. VI. 95. (4) Allantus arcuatus Forst., 21. VI. 95. Diptera. Syrphidae'. (5) Syrphus sp., 26. VI. 95. (6) Syritta pipiens L., sh. 24. VI. 96. E??ipidae\ (7) Empis bilineata Lw., sh. 15. VI. 99. (8) E. punctata Mg., sh. 24. VI. 96. (9) Hilara quadrivittata Mg., 18. VI. 96. Sarcophagidae : (10) Sarcophaga sp., sh. 24. VI. 96. Anthomyiidae'. (11) Hyetodesia incana W., sh. 19. VI.-17. VII. 95, 18. VI.-ii. VII. 96. (12) Trichophthicus cunctans Mg., sh. 19. VI. 95. (13) Trichophthicus sp., 16. VI. 95, 24. VI. 96. (14) Anthomyia sulciventris Ztt., 23. V. 97. (15 and 16) Anthomyia spp., 17-19. VI. 95, 24. VI. 96, 19. VI. 99. (17) Azelia aterrima Mg., sh. 19. VI. 95. Cordyluridae'. (18) Scatophaga stercoraria L., 15-20. VI. 95, 18-24. VI. 96, 19. VI. 99. Sciomyzidae : (19) Dryomyza flaveolaF., sh. 21. VI. 96. Coleoptera. (20) Meligethes aeneus F., 24. VI. 96. (21) Rhagonica limbata Thoms., 19. VI. 95. Thysano- ptera. (22) Thrips sp., 15. VI. 95. All at 800 ft., except 8 (at 900 ft.) and 15 and 18 also at 700 ft. 87 . Meum athamanticum, Jacq. [Lit. Alps 21b.] Each small umbel is terminated by an $ flower, and has a ring of 5 flowers outside, the intermediate being <$ ; and what is seen in these, is seen also in a modified degree in the large compound umbel ; for the intermediate umbels of it have more (usually) flowers than $ , the innermost generally and the outermost almost always having more 5 flowers than d- Visitors. Lepidoptera. Heterocera: Geometridae : (1) 1 sp., 15. Insects in Great Britain . 34i VI. 99. Tortricidae : (2) 1 sp., 17. VI. 99. Tineidae\ (3)1 sp., 17. VI. 99. (4) a second sp., 13. VI. 99. Hymenoptera. Aculeata: F or micidae : (5) Formica fusca Latr., 19. VI. 99. Myrmicidae : (6) Myrmica rubra L., 16. VI. 95. Petiolata parasitica: Ichneumonidae : (7) Alomyia debellator Fabr., 21. VI. 95. (8) Hemiteles?, 14. VI.-i. VII. 95. (9) Ichneumon sp., 22. VI. 96. Sessiliventres : Tenthre- dinidae : (10) Allantus arcuatus Forst., sh. and devouring flower, 14- 26. VI. 95, 18-29. VI. 96, 19. VI. 99. (n) Dolerus elongatus Htg., ? sh. 22. V. 96. Diptera. Syrphidae : (12) Platychirus manicatus Mg., 10-19. VI. 99. (13) Syrphus vitripennis Mg., sh. 25. VI. 95, 15. VI. 99. (14) Syritta pipiens L., 17. VI. 95. (15) Eristalis arbustorum L., 14-21. VI. 95. Empidae : (16) Empis tessellata F., 21-25. VI. 95, 14-16. VI. 99. (17) E. bilineata Lw., sh. and preying on flies, 21-22. V. 96, 17. VI. 99. (18) Rhamphomyia nigripes F., 22. V. 96. Bibionidae : (19) Dilophus albipennis Mg., sh. 19. VI. 96. (20) Bibio nigriventris Hal., 21. VI. 95, 17-19. VI. 99. Tabamdae : (21) Leptis scolopacea L., 17. VI. 95. Tipulidae\ (22) Tipula varipennis Mg., ? sh. 22. V. 96. Tachinidae\ (23) Gymnochaete viridis Fin., sh. 22. VI. 96. Sarcophagidae : (24) Sarcophaga sp., sh. 14-19. VI. 99. Muscidae : (25) Lucilia sp., 16. VI. 99. (26) Calliphora sepulchralis Mg., sh. and fp. 26. VI. 95. (27) C. erythrocephala Mg., sh. 16. VI. 99. (28) Pollenia Vespillo F., sh. 10-19. VI. 99. (29) Morrellia simplex Lw., sh. 22. V. 96. Anthomyiidae : (30) Hyetodesia incana W., sh. 15-21. VI. 95, 22. V. 96, 18-19. VI. 96, 13-19. VI. 99. (31) Mydaea sp., 16. VI. 99. (32) Spilogaster nigrivenis Ztt., sh. 19. VI. 99. (33) Limnophora solitaria Ztt., 15. VI. 95. (34) An- thomyia sulciventris Ztt., sh. and fp. 21.V. 96. (35 and 36) Anthomyia sp., 10-19. VI. 99. (37) Azelia aterrima Mg., sh. 21. VI. 25. (38) Coenosia sp., 13. VI. 99. Cordyluridae : (39) Scatophaga stercoraria L., sh. 21-22. V. 96, 16. VI. 96, 17. VI. 99. Sepsidae : (40) Sepsis sp., sh. 21-22. V. 96. Ephydridae\ (41) Hydrellia griseola Fin., 21. VI. 96. Chloropidae: (42) Ascinis sp., sh. 21. VI. 95. Phoridae\ (43) 1 sp., sh. 21. VI. 95. Coleoptera. (44) Meligethes viridescens F., 22. V. 96, 17. VI. 99. (45) Epuraea aestiva L., sh. 22. V. 96. (46) Tachyporus obtusus L., 17. VI. 99. (47) Rhagonycha limbata Thoms., 17. VI. 99. (48) Corymbites quercus Gyll., and its var. ochropterus Steph., sh. 21-24. VI. 95, 22. V. 96, 17. VI. 99. Hemi- ptera. (49) 1 sp., 22. V. 96. Trichoptera. (50) 1 sp., 17. VI. 99. All at 7-900 ft. 342 Wz/lzs and Bur kill, — Flowers and 88. Angelica sylvestris, Linn. [Lit. Brit. 23 , 39 ; N.C.E. 1, 3 a, 16 , 18 , 21 a, 34 ; Arct. 36 ; Alps 2 ; Pyren. 17 .] Visitors. Diptera. Anthomyiidae'. (i) Hyetodesia incana W. Coleoptera. (2) Meligethes viridescens F. Both 16. IX. 95, 800 ft. 89. Heracleum Sphondylium, Linn. [Lit. Brit. 23 ; N.C.E. 1, 3 a, 8, 10, 16 , 18 , 21a, 31 , 34 , 35 , 40 ; Alps 2, 16 , 34 .] The secretion of honey continues in a very marked manner after the fall of the petals. Visitors. Hymenoptera. Aculeata : Apidae: (1) Apis mellifica L., sh. 20. VII. 95, 11. VII. 96, 800 ft. Vespidae: (2) Vespa norvegica F., sh. 15. VII. 95, 800 ft. Sessiliventres : Tenthredinidae\ (3) Allantus arcuatus Forst., sh. freq. 5-25. VII. 95, 24. VI.-n. VII. 96, 7-800 ft. Petiolata parasitica: lchneumonidae\ (4) Hemiteles ?sh. 6. VII. 95, 25. VI. 96, 7-800 ft., ab. on second date. (5) 1 sp., sh. 2 2- 23. VII. 95, 22. VI.-11. VII. 96, 7-800 ft. and once at 2,300 ft. Diptera. Syrphidae : (6) Syrphus compositarum Verrall, sh. 22. VII. 95, 800 ft. (7) S. ribesii L., 17. VII. 95, 11. VII. 96, 7-800 ft. (8) Eristalis arbustorum L., sh. 11. VII. 96, 800 ft. Empidae'. (9) Empis tessellata F., 5-23. VII. 95, 7-800 ft. (10) E. bilineata Lw., 4. VII. 95, 800 ft. (n) E. punctata Mg., sh. 15. VII. 95, 800. ft. (12) Rhamphomyia sp., 20-29. VI. 96, 8-900 ft. (13) Hilara sp., sh. 5- 17. VIJ. 95, 7-800 ft. Mycetophilidae\ (14) Glaphyroptera fascipennis Mg., 25. VI. 96, 800 ft. Bibionidae\ (15) Scatopse sp., 3. VII. 96, 800 ft. (16) Dilophus albipennis Mg., 26. VI. 96, 2,300 ft. (17) Bibio pomonae F., sh. 10-11. VII. 96, 8-2,200 ft. Sarcophagidae : (18) Sarcophaga sp., 25. VI. 96, 800 ft. Muscidae : (19) Lucilia cornicina F., 5. VII. 95, 700 ft. (20) Calliphora erythrocephala Mg., sh. 15. VI.-17. VII. 95, 15-18. IX. 95, 25. VI -1 1. VII. 96, 7-800 ft. (21) C. vomitoria L., sh. 20-25. VI. 96, 800 ft. (22) Pollenia rudis F., sh. 12-15. VII. 95, 15-22. IX. 95, 11. VII. 9 6j 7-800 ft. (23) Pyrellia lasiophthalma Mcq., sh. 24. VI. 96, 800 ft. (24) Mesembryna meridiana L., sh. 17-22. VII. 95, 22. IX. 95, 24. VI-11. VII. 96, 7-800 ft. (25) Morrellia simplex Lw., 10. VII. 95, 800 ft. Anthomyiidae : (26) Polietes lardaria F., sh. 11. VII. 96, 800 ft. (27) Flyetodesia incana W., sh. 10-17. VII. 95, 22. VI.-u. VII. 96, 7-900 ft. and four individuals at 2,200 ft. (28) Limnophora solitaria Ztt., sh. and fp. 13. VII. 95, 10. VII. 96, 17-2,300 ft. (29) Trichophthicus sp., sh. 4-17. Insects in Great Britain . 343 VII. 95, 800 ft. (30) Anthomyia sulciventris Ztt., sh. 17. VII. 95, n. VIL 96, 800 ft. (31 and 32) Anthomyia spp., sh. 12-22. VII. 95, 21. IX. 95, 24. VI.— 1 1 . VII. 96, 8-2,300 ft. (33) Azelia Macquarti Staeg., sh. 17. VII. 95, 800 ft. (34) A. aterrima Mg., sh. 2-17. VII. 95, 3. VII. 96, 800 ft. Cordyluridae : (35) Scatophaga stercoraria L., 12-20. VII. 95, 25. VI.-3. VII. 96, 7-800 ft. (36) S. maculipes Zett., sh. 10-17. VII- 95 , 800 ft- ( 3 /) S. suilla Fabr., 10-17. VII. 95, 800 ft. Helomyzidae : (38) T ephrochlamys sp., sh. 10. VII. 96, 2,300 ft. Sapromyzidae : (39) Sapromyza sp., sh. 10. VII. 96, 2,300 ft. Sep- sidae\ (40) Sepsis cynipsea L., sh. 2-17. VII. 95, 24. VI.-11. VII. 96, 7-800 ft. Ephydridae : (41) Hydrellia griseola Fin., sh. 12. VII. 95, 700 ft. Chloropidae\ (42) Chloropisca ornata Mg., sh. 5. VII. 95, n. VII. 96, 7-800 ft. Phoridae\ (43) Phora rufipes Mg., 1-13. VII. 95, 11. VII. 96, 9-1,700 ft. Coleoptera. (44) Meligethes viridescens F., sh. 15-21. IX. 95, 22-26. VI. 96, 8-2,300 ft. (45) M. aeneus F., 4. VII. 95, 8-900 ft. (46) Anthobium ophthalmicum Payk., sh. 10. VIL 96, 2,200 ft. (47) Epuraea aestiva L., 4. VII. 95, 800 ft. Hemi- ptera. (48) Heterocordylus tibialis, 16. IX. 95, 800 ft. Thysanoptera, (49) Thrips sp., 26. VI.-10. VII. 96, 8-2,200 ft. A' § IO. CORNACEAE. 90. Cornus suecica, Linn. [Lit. N.C.E. 33.] This plant is little visited, but fruits not infrequently. It has a good deal of asexual reproduction by suckers. Visitors .• Diptera. Anthony iidae : (1) Limnophora sp., 28. VI. 95, 2,300 ft* (2) Hylemyia nigrescens Rnd., 13. VI. 99, 2,300 ft. Out of the whole available anthophilous insect fauna of (for the time of our observations) 17,30 6 individuals, 6,156 went to Class B', and 1,482 to the massed flowers of Class A, which we may here for brevity call Class A'. The species of plants obtained attention as in Tables IX and X, B' obtained many more of the desirable insects (see p. 315) than A', and very much fewer of the injurious, which could find but small encouragement where the honey is hidden (see Table XI). Class B' is found by our observations to fall very markedly into two divisions : one division contains the plants whose flowers belong to the rose-purple-lilac-blue series, the other The number of individuals observed on the flowers of Class B\ 344 Willis and Bur kill, — Flowers and April visitors in 1895 when no count was made. Insects in Great Britain. 345 contains those whose flowers belong to the yellow-white series. The latter is visited by less desirable insects than the former, and therefore, as shown in Tables XII and XIII, approaches A'. TABLE x. The number of individuals observed on the flowers of Class A'. < [ Bomb. d w j Tenthr. Parasit. C < Wasps. d. 8, 9, and 14 which illustrate this paper. IV. Summary of Conclusions. 1. The Melanconium found on diseased sugar-canes in the West Indies is a saprophyte and is not the cause of the ‘ rind ’ disease. The whole of the evidence obtained in these ex- periments points to this fungus being quite distinct from Thielaviopsis ethaceticus , Went. 408 Howard \ — On some Diseases of the 2. The macro- and micro-conidial phase of T richosphaeria Sacchari , Massee, identical with Thielaviopsis ethaceticus> Went, causes a disease of cane-cuttings in the West Indies which is the same as the ‘pine-apple’ disease of Java. In addition, it is a parasite on growing canes. 3. The ‘ rind 5 disease of the sugar-cane in the West Indies is identical with the ‘ red-smut ’ disease of Java, and is caused by the fungus Colletotrichum falcatum , Went. It can infect ripening canes at wounds and at old leaf-bases, and can over- come the tissues of young canes which are capable of growth and development. 4. Melanconium infects canes easily at points where they have been invaded by Colletotrichum. 5. The common root disease of the sugar-cane in Barbados is caused by the fungus Marasmius Sacchari , Wakker, the mycelium of which is able, under certain conditions, to over- come the growing-point tissues of the developing roots of the cane. Barbados, Aug . 30, 1902. Note added : — Thanks to the kindness of Professor Marshall Ward, I have been able to repeat the culture and inoculation experiments with Melanconium and Thielaviopsis , described in this paper, at Cambridge. Both these Fungi were grown in pure culture in a cane-extract food-material at a tempera- ture of 75 0 F., and the inoculation experiments were performed on mature sugar-canes growing in the Lily-house at the Botanical Gardens. No evidence of a genetic connexion between these two forms was obtained, neither did Melan- conium behave as a parasite towards the cane. On the other hand, the results were identical with those noted in the ex- periments in Barbados and described in the present paper. Mixed cultures of Melanconium and Thielaviopsis gave positive results when introduced into healthy canes. The Botanical Laboratory, Cambridge. Jan . 3, 1903. Sugar-Cane in the West Indies. 409 1. 1877. 2. 1890. 3. 1892. 4. 1893. 5. 1893. 6. 1893. 7. 1893. 8. 1894. 9. 1895. 10. 1895. 11. 1895. 12. 1896. 13. 1896. 14. 1898. 15. 1899. 16. 1900. 17. 1900. 18. 1900. 19. 1901. 20. 1901. 21. 1902. V. List of Papers Cited. O. Brefeld: Unters. iiber Schimmelpilze III, p. 17. H. Marshall Ward : On some relations between host and parasite in certain epidemic diseases of plants. Proc. Roy. Soc., vol. xlvii, PP* 393-443* H. Marshall Ward: The Ginger-beer plant and the organisms composing it. Phil. Trans., vol. clxxxiii, pp. 130-2. N. A. Cobb : Diseases of the Sugar-cane. Agricultural Gazette of New South Wales, vol. iv, p. 800. G. Massee : On Trichosphaeria Saccharic Massee. Annals of Botany, vol. vii, p. 128. F. A. F. C. Went : Het rood Snot. Mededeelingen van het Proef- station West Java. F. A. F. C. Went: De Ananasziekte van het Suikerriet. Meded. van het Proefstation West Java. Sugar-cane disease in Old World, Kew Bulletin, p. 81. J. H. Wakker: De stand der Suikerrietbladen bij vocht en bij droogte. Mededeelingen van het Proefstation Oost Java, Nieuw Serie, No. 3. J. H. Wakker : Eine Zuckerrohrkrankheit verursacht durch Maras- mius Sacchari, n. sp. Centralblatt fur Bakteriologie und Parasiten- kunde, Abth. II, Bd. ii, pp. 45-56. Prillieux et Delacroix: Sur une maladie de la canne a sucre produite par le Coniothyrium melasporum (Berk.). Sacc. Bull. Soc. Mycol. de France, tom. xi, p. 75. F. A. F. C. Went : Onderzoekingen omtrent de chemische physiologie van het Suikerriet. Meded. van het Proefstation West Java, No. 25. F. A. F. C. Went : Notes on Sugar-cane diseases. Annals of Botany, vol. x, p. 583. J. H. Wakker and F. A. F. C. Went : De ziekten van het Suikerriet op Java. W. Kruger : Das Zuckerrohr und seine Kultur. W. T. Thiselton-Dyer : Note on the Sugar-cane disease of the West Indies. Annals of Botany, vol. xiv, p. 609. A. Howard : On Trichosphaeria Sacchari , Massee. Annals of Botany, vol. xiv, p. 617. Engler und Prantl : Die natiirlichen Pflanzenfamilien, Fungi. 1. Teil, i. Abteilung, pp. 403-5. C. A. Barber : Sugar-cane in the Godavari and Ganjam districts. Department of Land Records and Agriculture, Madras, vol. ii, No. 43. H. Tryon : Some obstacles to successful Sugar-cane cultivation. Queensland Agricultural Journal, vol. ix, p. 85. A. Howard : The field treatment of cane-cuttings in reference to fungoid diseases. West Indian Bulletin, vol. iii, No. 1, p. 73. 410 Howard. — On some Diseases of the EXPLANATION OF FIGURES IN PLATE XVIII. Illustrating Mr. Howard’s paper on Diseases of the Sugar-Cane. Fig. i. Portion of a sugar-cane attacked by the ‘rind’ disease showing stromata of C . falcalum above and below the leaf-base. Nat. size. At ( a ) is a stroma of the fungus as seen under a lens. Fig. 2. A portion of a sugar-cane, attacked by the ‘rind’ disease, split in half. A red blotch with a white centre is shown at (a). Nat. size. Fig. 3. Stages in the germination of a spore of C. falcatum in a hanging drop. The sowing was made at 1 p.m., Nov. 29. a = 4 p.m., Nov. 29) b = 5.40 „ „ h x 375- . c = 9.10 „ „ ) d = 8 a.m. Nov. 30. x 60. Temperature throughout 28-31° C. Fig. 4. Stages in the formation of conidia from the mycelium of C. falcatum in a hanging-drop culture. The sowing was made at 1 p.m., Nov. 29. a — 12.45 p.m., Nov. 30 } 1 > = „ » f x 375- * = 3-50 ,, „ ’ Temperature 29-30° C. throughout. Fig. 5. Production of chlamydospores on the submerged hyphae of C. falcalum in a hanging drop twenty-seven hours after sowing. x 375. Fig. 6. Formation of conidia of C. falcatum at stromata formed in a hanging drop. The sowing was made at 1 p.m., Nov. 29, the temperature was 30-31° C. throughout, and all are shown x 375. a = 10.25 a.m., Dec. 5. b = 12 (noon) „ c = 5 P- m - „ Fig. 7. A sugar-cane stem attacked by the fungus Marasmius Sacchari showing the aborted roots and an abnormal development of the lower buds. Fig. 8. A portion of the below-ground part of the stem of a similarly diseased cane showing the aborted roots on a larger scale. Fig. 9. A portion of the lower (above-ground) part of the stem of a diseased sugar-cane showing colonies of the fructifications of Marasmius Sacchari. Fig. 10. Brown, thick- walled, usually terminal, chlamydospores in the mycelium of Marasmius. Fig. 11. Longitudinal section of a developing root of the sugar-cane destroyed by the mycelium of Marasmius. The periblem is penetrated by the fungus in all directions, many of its cells being brown in colour and much disintegrated. The root-cap is almost completely destroyed and the shaded portion of the pleurome is filled with mycelium. x 35. Sugar-Cane in the West Indies. 411 Fig. 12. Stages in the germination of a spore of the fungus in a hanging drop. The sowing was made at 2 p.m., Dec. 3. a = 3.30 p.m., Dec. 3' *> = 4-30 „ » • x 375* c = 6 „ „ Temperature throughout 29 0 C. Fig. 13. Stages in the formation of a clamp-connexion in a hanging-drop culture. The papilla in (a) arose about 100 fx from the growing-point of a hypha and the arrow indicates the direction of growth. Temperature 30° C. throughout. (Zeiss, D D.) a = 1 1.4 a.m., Oct. 4 b = 11. 7 „ C= 11-20 „ „ d = 11.25 „ , e = 11.35 „ /= 12.15 p.m. „ Fig. 14. Production of rhizomorphs on the walls of a culture-tube nine months after infection. Above, these bodies shade off into white feathery mycelial strands. Ee? . 4 "^ ■ . . Wmmrn A. HOWARD. — ON SOME DISEASE ^/Innals of Botany ) University Press. Oxford. HE SUGAR CANE IN THE WEST INDIES. The Root-Structure of Dioscorea prehensilis. BY T. G. HILL, A.R.C.S., F.L.S., Demonstrator in Biology at St. Mary's Hospital Medical School , London . AND Mrs. W. G. FREEMAN, A.R.C.S. With Plate XIX, and a Figure in the Text. HE publication of a paper by Dr. D. H. Scott 1 placed 1- botanists in possession of two new examples of spine- bearing roots. Of the plants considered one, Dioscorea prehen- silis , Benth., forms the subject of the present communication. The plant described by Dr. D. H. Scott was grown at Kew, and the tuber was entirely a subterranean organ. It appears, however, that in the natural state the tuberous stem is almost entirely an aerial structure, a fact which is very clearly demonstrated by a photograph of the wild plant, taken by Mr. G. F. Scott-Elliot. The following interesting remarks are quoted from a letter from Mr. G. F. Scott-Elliot to Dr. Scott, which the writer has kindly allowed us to make use of. ‘The plant was, I should say, 7 feet high and completely covered by the arched roots. ... It was photo- graphed and collected in a day’s march, and there is not, I think, very much Natural History to be found from such hurried observations. I have an impression that this country has many wild boar who are possibly the enemy. It is not, 1 Scott, D. H. : On two new instances of Spinous Roots, Annals of Botany, vol. xi, 1897. [Annals of Botany, Vol. XVII. No. LXVI. March, 1903.] 414 Hill and Freeman . — The Root-Structure I think, a forest district, but it is in the “Acacia zone,” i. e. scattered trees of Acacia at 20 to 30 feet apart and the colour of the soil showing through a scanty sedge and grass sward. Game is abundant in the neighbourhood, man is absent. The climate is very dry, but there is probably under- ground water within 20 feet of the surface. There may be no rain for nine months or so.’ In the material at our disposal the thick roots possessed spines which varied in their characters according to the state of their development. The youngest, although often fully grown, were quite soft and gradually tapered off into a fine termination bearing rootlets in the ordinary manner ; others were quite hard and sharp. The question which here arises is whether the normal root-ending of some of the softer spines represents a normal condition or not. It will be borne in mind that the large spine-bearing roots are, in the natural state, aerial ; and the possibility is not excluded, indeed it is very probable, that under these circumstances the spines when above ground do not terminate in a normal root ; this con- dition only obtaining when the organs are buried. It is not possible to clear up this point here, inasmuch as the necessary evidence is as yet wanting. However, dealing with the roots at our disposal, it is seen that the absorbing end of the spinous root sooner or later drops off, leaving behind a perfect sharply-pointed spine. This may be ex- plained either on physical or physiological grounds. It was noticed that on dropping into clove oil a spine which had not yet lost its apical region, it immediately curled up at the tip, became brittle, and on being touched separation took place between the absorbent tip and the thick basal part. Some- thing similar to this may occur naturally in the buried roots, although it is much more probable that the absorbent tip shrivels up hopelessly during the dry season. On the other hand the breaking may be due to the cutting off of food- supplies, for the cortex generally has a withered appearance before the actual severance takes place. And further, the sieve-plates in the basal parts of the spinous roots were 4i5 of Dioscorea prehensilis. invariably blocked by callus, which fact probably points to the conclusion that the cause Is physiological rather than mechanical. The breaking is not effected at any one particular point ; there is rather an ill-defined region where the transverse severance may occur. Sections taken above and below the rupture, where the apical region was preserved, exhibited no anatomical charac- ters such as are found in the separation-layer of a leaf. The first sign of breaking in a young spine (PL XIX, Fig. i C) is a slight brown annular discoloration in the region indicated by the line X- F, and sections show that here the softer tissues are withering. The portions of the root nearer the apex appear quite healthy, hence it is obvious that the rupturing is not caused by the mere dying of the tissues from the apex backwards. In a more developed spine the discoloration-zone is seen to be still more marked and the separation is almost com- plete, connexion only being maintained by shreds of cortex (Fig. i D). Besides these large spine-bearing roots the tuber also possesses much smaller roots, having numerous lateral root- lets which are clearly absorbent in function. These secondary roots, after dying off, also leave behind a small hard spine similar to those of the larger roots; a fact which has already been pointed out by Dr. Scott L Indeed, it may be stated at once that there is no essential difference either in the morpho- logy or anatomy between the two varieties of roots, the dissimilarity being only in the size. Structure. Our knowledge of the anatomy of the roots of the Diosco- reaceae is based chiefly on the researches of Bucherer 2 who, in his work on the anatomy of this natural order, confines 1 Loc. cit„, p. 329. 2 Emil Bucherer : Beitrage zur Morphologie und Anatomie der Dioscoreaceen, Bib. Bot., Heft 16, iii, 1889. 4i 6 Hill and Freeman. — The Root-Structure himself chiefly to the origin, &c., of the roots and the characters presented by their bundle-sheath in species of Tamus and Dioscorea. Further, he confirms Treub’s 1 statements regard- ing the differentiation of the root-apex of Tamus communis , and disagrees with those of Janczewski. Anatomy of the large spine-bearing roots. These roots attain a diameter of 7 cm. and, as regards their structure, conform to the general monocotyledonous type. There are, however, certain interesting features exhibited which render a brief account of their structure not altogether out of place. The apex is somewhat blunt, and is made up of an enormous number of very small cells. Inasmuch as our material contained but one good and one indifferent apex, it was not possible unfortunately to investigate thoroughly the apical differentiation ; however, it appears most probable that there is, in this plant, no definite calyptrogen layer as has already been asserted by Treub *, and confirmed by Bucherer 2 , to be the case in the Dioscoreaceae among other Natural Orders. From a series of transverse sections through the apex it may be seen that the central cylinder is of normal diameter, and before either the phloem or xylem is differentiated a number of canals or vessels are formed in the more central regions, roughly arranged in a circle within the zone which eventually will be occupied by the phloem and xylem. The development of these vessels is extremely remarkable and quite dissimilar to what obtains in other plants as far as is indicated by existing accounts. They are produced not merely by the obliteration of the end-walls of elements situated one above the other, but also by the breaking down of the lateral walls of contiguous cells in a transverse plane. It is not suggested, however, that these structures are formed wholly by such a lateral fusion of elements ; for tracing them downwards from the apex it is found that they originate as 1 Treub : Le meristeme primitif de la racine dans les Monocotyl^dones. Leiden, 1876. 2 Loc. cit. of Dioscorea prehensilis . 417 a single row of elements somewhat larger than the surrounding cells. Only one case was seen in which the appearance of Fig. 19. — 1-6 illustrating the origin of one of the central vessels of the large spine- bearing roots. 7-12 showing the cell- walls within the lumen. the first origin of a central vessel suggested an initial absorption of the lateral walls of contiguous cells (Text- Fig. 19, 1-6). Increase in size takes place, and sooner or later transverse walls, in varying stages of completeness, are seen stretching across the lumen. The majority of these 41 8 Hill and Freeman . — The Root-Structure walls shows signs of disintegration, and their presence may be seen in several successive sections. Further, the nuclei of the cells originally bounded by these walls are very obvious (PI. XIX, Fig. 2; and Text-Fig. 19, 7-12). Further back the lumen is again quite clear and contains but few nuclei, but still nearer the base of the root a large number of nuclei, sometimes as many as twelve in a single transverse section, occur at various levels marking the regions where the fusion of a number of cells took place. The only obvious explanation which will account for the foregoing facts is that these central vessels arise very generally as single rows of elements, but the initial cells of any one vessel may not always be situated immediately one above the other to form a continuous string as in many cases, but are separated by intervening cells the walls of which ultimately break down, and so there is produced a continuous vessel. It sometimes happens that these vessels may not reach a great length, for although many may be traced through, relatively speaking, long distances, some come to an end quite suddenly ; this more especially was found to be the case when two had been formed quite close together and separated only by the common wall. Finally they become lignified in common with the other parts, with the exception of the phloem, of the vascular cylinder, and possess bordered pits. Whether or not this curious development is due to the fact that the roots examined were from an abnormally grown plant, cannot be decided at present. It is hoped that more material will be obtained and the matter investigated further. The structures above described are not the only ones which are multinucleate, for certain of the inner vessels of the metaxylem, which are the first to originate, together with the larger sieve-tubes, frequently have as many as four or five nuclei at one level 1 . It is doubtful whether these follow the 1 Since this present paper was written, it has been found that Buscalioni in a recent preliminary communication (‘ Sull’ anatomia del cilindro centrale nelle radici delle Monocotiledoni,’ Malpighia, 15, 1902) has drawn attention to the fact that the mother-cells of the tracheae of the roots of the Dioscoreaceae and of Dioscorea prehensilis . 419 course of development already described for the central vessels ; in the case of the sieve-tubes there is absolutely no evidence to show that such is the case. Before the differentiation of the xylem and phloem, adjacent cells fuse together at various parts of the cortex to form mucilage reservoirs. These are very numerous ; in one trans- verse section as many as 130 were counted, and they develop rapidly. Eventually they become filled with bundles of raphides, and these may possibly subserve a protective function for the period during which the root remains soft. In longi- tudinal section these sacs are seen to be long, and they are situated one above the other forming long strings. The central cylinder increases in diameter, and as it does so the vascular elements are differentiated. As in many roots of Monocotyledons the number of phloem- and xylem-groups is very large, thirty of each being not an uncommon number in the plant under discussion. Sieve-areas occur on the lateral walls of the larger sieve- tubes, and a well-marked exodermis is present at the periphery of the cortex. There is nothing further worthy of record until the general lignification of the vascular strand sets in. The first portions to thicken are the regions immediately external to the phloem- groups. This is illustrated in Figs. 3 and 4, from which it may be seen that a crescentic mass of fibres encase the external region of the phloem. In order to ascertain whether or not this peculiarity obtained in other plants of the Dioscoreaceae, the roots of Tamils com- munis and an unnamed species of Dioscorea (labelled Pehio Yam) were examined. In both cases, although the lignification may become general, it was found that the regions external to the phloem-groups were not remarkable in being the first to be so markedly lignified. Returning to the case of Dioscorea prehensilis , induration proceeds inwards towards the centre of the stele, and out- Asparagaceae are multinucleate ; he also finds that the development of the xylem is centrifugal. 420 Hill and Freeman . — The Root-Structure wards; the tissue external to and opposite the phloem-groups is, however, much thicker- walled. Finally the cortex withers, and thus are formed roots of a high degree of hardness and bearing spines, the structure of which will be considered below. For the sake of comparison the smaller and less modified roots, the essential function of which is absorption, were examined. These organs do not depart in any important feature from those of the larger roots as set forth above. Those differences that do obtain are to be solely attributed to the relatively large size of the latter as already described ; thus instead of possessing thirty xylem-groups, the smaller roots never exhibited more than eight or ten. As regards histological features there are again no essential features of difference between the two forms, and in both the tissue directly bordering on the outer side of the phloem is the first to become lignified. Figs. 5 and 6 illustrate the structure of these smaller roots. Anatomy of the large spines. These thorns originate as very thick lateral roots (Fig. 7), and it is only at the extreme apex that a normal root-structure can be discerned. The phloem and xylem of the spines are connected respectively to the similar tissues of the parent root by a large number of strands. In the case of the phloem these connecting strands are very numerous, being often related to as many as half the total number of phloem-groups present in the parent root (Fig. 7). A transverse section near the base of a spine shows the phloem to be distributed around the periphery of the central cylinder in small groups isolated one from the other (Fig. 8), the xylem being restricted to two large lateral masses with smaller groups lying between them ; these latter are the first to fuse with the xylem of the main root. The examination of a series of sections from the base to the apex of a thorn shows that the phloem-strands travel in an irregular manner throughout the whole area of the stele. of Dioscorea prehensi Us. 421 Their course is sinuous, and as the apex is reached they anastomose with one another; hence just behind the extreme ap'ex of a young spine it is found that there are but few phloem-groups, and these are arranged in quite a normal manner (Fig. 9, a-e). This wide scattering of the phloem, coupled with the numerous connexions with the corresponding tissue of the main root, is probably to be correlated with the induration of the fully developed spine ; for it is obvious that during the process of lignification much material, relatively speaking, must be required and must be well distributed for the purpose. The arrangement of the tissue in question is excellently adapted to facilitate such a process of lignification on a large scale. Tracing the course of the xylem in a similar manner, it has already been stated that at the extreme base of the thorn the xylem is chiefly restricted to two large peripheral (just within the phloem-ring) masses, somewhat crescentic in shape, and that between these, smaller groups — which are the first to be connected with the xylem of the parent root — occur. The junction is effected chiefly by very short tracheides. Sections cut nearer the main root exhibit longitudinal strands of xylem between the two crescentic masses ; these represent the xylem rays of the parent root. Passing towards the apex of the spine it is found that the xylem is more evenly distributed, and is generally restricted to the more central regions. As the apex is reached it diminishes in amount and gradually takes up a position towards the centre of the stele (Fig. 10). At the extreme apex it is generally aggregated into three or four groups alternating with the phloem in a normal root-like manner. The abnormalities above described may at first sight appear remarkable, especially when a fully matured spine is examined; but it is to be borne in mind that no induration of the parenchymatous tissue sets in until the lateral root has attained its maximum size. The soft ground tissue of the basal region of the spine is the first to become lignified, 422 Hill and Freeman . — The Root-Structure and the peripheral parts of the stele thicken up before the more central. Fig. 1 1 illustrates the structure of a spine viewed in trans- verse section. A mature spine is seen to be made up chiefly of elements with very thick lignified walls, amongst which are scattered small isolated groups of phloem and conducting xylem-elements. The cortex of younger thorns possesses tannin-cells, and sometimes these elements may be found in the stele. In longitudinal section it is seen that fibres predominate ; the phloem pursues an irregular path, and cross-connexions occur between neighbouring groups. Sieve-plates may be observed at rare intervals, and the conducting xylem-elements are much longer in the central regions than those, already described, at the base. Summary. 1. In the natural state the tuberous stem is aerial. 2. The tuber possesses large spine-bearing roots, and smaller roots chiefly absorbent in function. The lateral rootlets of the latter, after dying off, leave behind a small hard spine similar to those of the larger roots. 3. The large spines of the material examined, when in the young state, tapered off into a normal root-ending. This absorbing end of the lateral spinous root eventually separates off, leaving behind a perfect spine. 4. Induration of the vascular cylinder of the thorn does not set in until the maximum size has been attained. 5. The apex of the large spine-bearing roots has no definite calyptrogen layer. 6. The central vessels of these organs are multinucleate and appear to be produced not merely by the obliteration of the end-walls of elements situated one above the other, but also partly by the breaking down of the lateral walls of con- tiguous*' cells in a transverse plane. 7. Certain of the inner vessels of the xylem-rays, the of Dio scored prehensilis. 423 development of which is centrifugal, are also multinucleate, as also are some of the larger sieve-tubes. It is doubtful whether these structures follow the same course of development as the central vessels. 8. The vascular strands of the spine-bearing roots become very hard, the regions immediately external to the phloem- groups being the first to become lignifiedf* 9. The large spines originate as thick lateral roots, and it is only at the extreme apex that a normal root-structure obtains. 10. At the base of these thorns the phloem-groups are arranged in a circle at the periphery of the central cylinder ; as the apex is reached it is seen that the phloem-strands travel in an irregular manner throughout the whole area of the stele. Their course is sinuous, and they anastomose with one another ; at the extreme apex the phloem consists of but few strands arranged normally. This arrangement is probably to facilitate the extensive lignification of the spine. 11. At the base of the thorn the xylem is chiefly restricted to two large peripheral masses just within the phloem-ring. Towards the apex the xylem is more evenly distributed, and gradually takes up a position nearer the centre of the stele. The Royal College of Science, South Kensington. 424 Hill and Freeman. — Dioscorea prehensilis. EXPLANATION OF FIGURES IN PLATE XIX. Illustrating Mr. Hill’s and Mrs. W. G. Freeman’s paper on Dioscorea prehensilis. Abbreviations: end., endodermis ; p.c ., passage cell; ph ., phloem; ph.s., phloem-strand ; xy., xylem. Fig. i. Portion of a large spine-bearing root. Fig. 2. Illustrating the development of the large vessels in the inner regions of the vascular cylinder of a large spine-bearing root. Fig. 3. Part of a transverse section of a similar but older root, showing the highly lignified tissue external to a phloem-group. Fig. 4. Similar section from an older root. Fig. 5. Diagram of a transverse section of one of the smaller absorbent roots. Fig. 6. Portion of Fig. 5 in detail. Fig. 7. Diagram, showing origin of a large spine. Fig. 8. Diagrammatic transverse section near the base of a spine, showing the disposition of the phloem and xylem. Fig. 9. Diagrams of a series of transverse sections of a spine, illustrating the gradual fusion of the phloem, from the base (a) to the apex (e); stele only represented. Fig. 10. Diagram of a transverse section of the vascular cylinder of an immature spine. Fig. 11. Transverse section of part of the stele of an older spine, but still not fully developed. HILL AMD FREEMAN. — ROOTS OF DIGSCOREA PREHtNSILiS. Vol. XVII.. PL XIX. Univei'sity Press, Oxford. //nncds of Bota.ni/ Vol XVII,. PL XIX. fidSe; fo University Press. Oxford. HILL and FREEMAN ROOTS OF DIOSCOREA PREHENSILlS On the Roots of Medullosa anglica. BY E. A. NEWELL ARBER, M.A., F.G.S., Trinity College , Cambridge ; University Demonstrator in Palaeobotany. With Plate XX. HE first British specimens of Medullosa , a genus of J- Palaeozoic plants belonging to the Cycadofilices, were described by Dr. Scott 1 in a very interesting and complete memoir, published in 1899. Dr. Scott there gave the first account of the structure of the roots of a Medullosa . A short time ago it was found that one of the petri- factions belonging to the Binney Collection in the Wood- wardian Museum, Cambridge, contained a portion of a stem of Medullosa anglica , Scott, with which several roots were associated. No section of this specimen could be found 2 , although the petrifaction had been cut previous to the presentation of the collection to the University in 1892. So far as I am aware, Binney did not refer to this specimen in any of his papers. 1 Scott, Phil. Trans. Roy. Soc., Ser. B, vol. cxci, 1899, p. 81. 2 A section of Medullosa anglica (S. 3533), formerly in the possession of Sir Joseph Hooker, and now in the General Collection of Sections of Fossil Plants in the Geological Department of the British Museum (Nat. Hist.), which was undoubtedly cut from a Binney specimen, may very possibly have been derived from the Cambridge specimen. I am indebted to Professor F. W. Oliver for calling my attention to this section. [Annals of Botany, Vol. XVII. No. LXVI. March, 1903.] F f 426 A rber. — On the Roots of Medullosa anglica. There is unfortunately no record of the locality from which the fossil was obtained. Mr. Lomax, however, who has recently made several excellent sections of the stem and the roots, tells me he is certain, from the appearance and preserva- tion of the material, that it was originally obtained from the Lower Coal Measures of Hough Hill Colliery, Stalybridge, Lancashire ; the same locality and horizon as the type specimens. The examination of the structure of the stem, which in the Cambridge specimen is unfortunately incomplete, has added nothing of importance, with one exception, to the very com- plete account already given by Dr. Scott ; which was founded on a study of several different specimens. In association with the stem, and in one case in continuity with it, several exceptionally well-preserved roots occur. These agree very closely in structure with the roots pre- viously figured 1 , and they undoubtedly belong to Medullosa anglica . Some of these are the best-preserved specimens which have yet been found, for the more delicate tissues, especially the phloem, are almost perfect. A photograph of a transverse section of one of these roots is shown on PI. XX, Fig. 1 (compare also Fig. 6). The diameter is about 9 mm. The root is triarch, as are all the other roots of Medullosa which I have examined. The ex- ternal tissue consists of a somewhat narrow but well-marked zone of radially seriate elements, the periderm ( pd ’.). As Dr. Scott 2 has pointed out, this periderm is developed centri- petally from a phellogen (see Fig. f i^ph.gl) which lies on the inner side of this zone. It was also shown that this peri- derm is of deep-seated origin, arising, probably, in the pericycle 3 . Internal to the periderm, there is a somewhat broader zone of thin-walled tissue (sr), with here and there very conspicuous cells, or groups of cells, with dark-coloured contents. This 1 Scott, loc. cit., PI. VIII, photos 19-25 ; PI. XII, Fig. 19 ; PI. XIII, Figs. 20-4. 2 Scott, loc. cit., p. 102, PI. Vlil, photo 21. 3 Scott, loc. cit., p. 104, PI. XII, Fig. 19. Arber.—On the Roots of Medullosa anglica . 427 zone is exceptionally well preserved, and the evidence as to the nature of the tissues composing it is probably more complete than in the specimens which have previously been described. These tissues will be referred to presently in greater detail. The rest of the root consists of an exceedingly regular triarch strand of xylem. The protoxylem-elements (p.x.) lie on the inner margins of three large bays or concavities, which occur at regular intervals in the almost circular outline of the strand. The elements of the primary wood can be seen extending from the protoxylem-groups to the centre of the root. The secondary wood (x 2 .) is formed of three large plates of radially disposed elements, with convex outer surfaces. The rays of woody elements composing the plates are generally one or two rows of tracheides, with multiseriate bordered pits on their radial walls. The medullary rays are often perfectly preserved. The parenchymatous cells of the ray are rounded, except where they have become elongated radially, probably as the result of stretching accompanying the increase in the dimensions of the secondary wood. As a rule no secondary xylem-elements are formed opposite the protoxylem-groups. The vascular system of the secondary roots has, however, its origin in this position, and the xylem- strand, seen in one of the concavities ( r.x .), is in connexion with a rootlet, which arises at some distance further along the root. These roots differ somewhat in shape from some of those previously figured. The structure is, however, identical in both cases. Dr. Scott has made out in considerable detail the minute anatomy of the triarch strand, and I have nothing to add to our present very complete knowledge on this subject. We may now consider in greater detail the structure of the zone of thin- walled tissue lying internal to the periderm, abutting on the convexities of the secondary xylem, and usually filling the concavities opposite the protoxylem-groups. F f 2 428 Arber. — On the Roots of Medullosa anglica. The Phelloderm and Pericycle. A portion of a very thin transverse section is figured on PI. XX, Fig. 2. It shows the thin-walled tissue opposite one of the protoxylem-groups (p.x). The cells are fairly large, polygonal, or somewhat rounded parenchymatous elements, and are not very dissimilar in size or arrangement. Towards the periphery of the section, in the lower part of the photograph, a small portion of the periderm (p.d.) can be seen. Immediately internal to the phellogen ( ph.g) } some fairly large cells are shown lying on the same radii as the periderm-elements. This is no doubt phelloderm ( ph.d .), produced by the activity of the phellogenetic meristem. In certain sections in which the preservation is particularly favourable, the origin of these cells can be clearly traced from divisions of the phellogen layer. The thickness of phelloderm is probably quite small. At a short distance from the phellogen the radial arrangement of the cells is lost. Internal to the phelloderm, there occurs a fairly broad band of parenchymatous tissue ( p.c .), the cells of which are irregu- larly arranged. These elements constitute the pericycle. Conspicuous among the elements of the pericycle, single cells or groups of cells occur, with dark contents. These are regarded as ‘ secretory sacs V They appear to be ordinary parenchymatous cells in all the sections of these roots which I have examined. They therefore differ in structure from the gum-canals, which are so abundant in the petiole of Medullosa 2 . The ‘ secretory sacs ’ occur not only in the peri- cycle, but among the parenchymatous elements in all parts of the root, including those of the phloem and the primary xylem, as is clearly seen in Figs. 1 and 6. The dark colour of the cells is no doubt due to some organic change which the cell-contents have undergone before, or at the time of, preservation. The distribution of these ‘ secretory sacs ’ 1 The term is used in the same sense as in De Bary’s Comparative Anatomy (Eng. edit.), 1884, p. 136. 2 Scott, loc. cit., p. 99. Arber . — On the Roots of Medullosa ang licet. 429 rather recalls that of the crystal-containing sacs of certain recent plants, e. g. Solatium tuberosum . There is, however, in this case no evidence that these ‘secretory sacs’ were of a similar nature. In a few cases the cell-contents were found to be much less altered than is usually the case, but even these afforded no clue to the nature of the original substance. The parenchymatous tissue in the upper portion of the photograph, occupying the concavity on the inner side of which lies the protoxylem-group (p-x.), is the very broad main medullary ray ( m.r .) 1 . Secondary xylem is usually absent in this position. The small xylem-strand (r.x.) seen in the photo- ‘ graph belongs to the xylem of a secondary root, which, as already mentioned, has its origin in this position. The Phloem. The photograph of a transverse section of a root, figured on PI. XX, Fig. 3, shows a portion of the thin-walled zone of tissue opposite one of the xylem convexities. The tissues seen here include the phloem, which was of course not present in the section just described. At the lower end of the photo- graph, a few of the elements of the periderm ( p.d .) and phelloderm are seen. Next comes a broad band of large- celled, irregularly disposed elements, the pericycle (p.c.). The ‘ secretory sacs ’ with dark contents form large groups in this section. The upper half of the photograph shows a well-marked tissue, the elements of which are somewhat tangentially elongated. This is the phloem-zone (b.z.). The secondary phloem (< h 2 .) consists of radial groups of rather small cells, the sieve-tubes (s.t.) } alternating with rays of much larger phloem-parenchyma (bp.). The secondary bast as a whole has much the appearance of that of the stem of Heterangium tiliaeoides , Will. 2 . The groups of secondary phloem, corre- sponding to the groups of woody elements in the xylem- 1 De Bary, loc. cit., p. 474. 3 Williamson and Scott, Part III, Phil. Trans. Roy. Soc., Ser. B, vol, clxxxvi, 1896, p. 761, PI. XXIX, Fig. 35. 43 ° Arber. — On the Roots of Medullosa cinglica. plate, and separated by dilated parenchymatous rays, are characters common to these two plants. The sieve-tubes are also accompanied by a good deal of conjunctive parenchyma, as in Heterangium. In Medullosa , however, numerous ‘ secre- tory sacs ’ occur between the elements of the bast, and also among the cells of the parenchymatous rays, as is clearly seen in the photograph. The sieve-tubes in the root of Medullosa anglica are, as far as I can ascertain, without the apparently thickened walls and narrow lumen, which are so characteristic of those of the stem 1 . But, like the sieve-tubes of the stem, they have lateral sieve-plates, similar to those of the phloem of most recent Ferns and Gymnosperms. On PI. XX, Fig. 4, a photograph of a drawing of highly magnified sieve-tubes from the stem of the Binney specimen is shown. The sieve-plates (. sp .) are clearly seen as little patches on the lateral walls. In the roots, lateral sieve-plates also occur, as is shown in the drawing figured on PI. XX, Fig. 5. It is only fair to add that Dr. Scott, who has examined the Binney sections, and most kindly given me the benefit of his opinion on several points in the anatomy of these roots, first recognized and pointed out to me the occurrence of lateral sieve-plates in the phloem of both stem and roots. I may therefore take this opportunity of expressing my thanks to Dr. Scott for much help in the examination of this material. Lateral sieve-plates have been previously recognized in the phloem-elements of the stem of Heterangium tiliaeoides 2 , and by Professor Renault 3 in the stem of Poroxylon Edwardsi, Ren. As far as I am aware, this is the first occasion in which they have been distinguished in the root of a fossil plant. The external margin of the phloem-zone is composed of very tangentially elongated cells without any radial arrangement. 1 Scott, loc. cit., p. 90, PI. X, Fig. 3. 2 Williamson and Scott, loc. cit., p. 762, PI. XXIX, Figs. 37 and 38 a. 3 Renault, Etud. Gites Min^r. Bass. Houill. et Perm. d’Autun, 1896, p. 282, PI. LXXIV, Fig. 1 1. Also Bertrand and Renault, Recherches sur les Poroxylons, Arch. Bot. N. France, 1886, Figs. 192-3. Arher. — On the Roots of Medullosa anglica . 431 This is no doubt the primary phloem (b 1 .). It corresponds very closely to the primary phloem in the stem of Heter- angium tiliaeoides 1 . In this section the primary phloem is very clearly marked off from the outer large-celled tissue, the pericyle. The Secondary Roots. The main points in the structure and origin of the secondary roots of Medullosa have been already described by Dr. Scott 2 . The examination of a large series of sections of a root con- tained in the Binney material has, however, resulted in the elucidation of a few additional details. The transverse section of a root figured on PI. XX, Fig. 6, shows the base of a rootlet or secondary root (r./.). The structure of the root itself is precisely similar to that just described (Fig. 1 ). The particular rootlet shown in the photograph is, however, stunted and abnormal. The xylem- elements are very small, and much less developed than is usually the case, and probably the rootlet never functioned as a typical root. The lateral roots arise in three rows on the roots, at points opposite the protoxylem-groups. There is apparently, in all the roots which I have examined, some little distance between successive lateral roots in the same row ; and only one rootlet is given off in any one transverse plane. The ramification is therefore not so abundant as in certain roots of Lygino - dendron 3 . The xylem-strand of the rootlet arises, as we have seen, opposite a protoxylem-group of the triarch root. It then passes outwards obliquely, and not at right angles to the stele of the root, as in Lyginodendron 4 . The parenchymatous tissues of the rootlet arise from the divisions of a group of meristematic cells, probably of pericyclic origin, which cause a protrusion of the periderm of the root at some little distance 1 Williamson and Scott, loc. cit., p. 761, PI. XXIX, Fig. 35. 3 Scott, loc. cit., p. 103, PI. VIII, photos 19 and 21. 3 Williamson and Scott, loc. cit., p. 740. * Ibid. 432 Arber . — On the Roots of Medullosa ang licet* in front of the point of origin of the xylem-elements. This protrusion becomes more and more marked, until finally the rootlet becomes cut off, and a new growth of periderm com- pletes the outer sheath of tissue of both the root and rootlet. For a short time after it has become free, the rootlet lies in a groove or inflection of the periderm of the root. One of these grooves can be seen in nearly every transverse section (PL XX, Figs, i and 6,gr.) y opposite a protoxylem-group. Conclusions. The examination of the roots of Medullosa in the Binney specimen has resulted in a more complete knowledge of the thin-walled tissues which lie between the xylem and the periderm. The most noteworthy points are, the presence of a thin zone of phelloderm, the structure of the phloem, and the discovery of lateral sieve-plates on the phloem-elements of both the stem and roots. In the phloem of Medullosa , we have another point of agreement between Medullosa and Heterangium. The structure of the root of Heterangium tiliaeoides is at present unknown, but the phloem in the roots of Medidlosa anglica closely resembles that of the stem in the former species. Arber . — On the Roots of Medullosa anglica. 433 EXPLANATION OF PLATE XX. Illustrating Mr. Arber’s paper on Medullosa anglica . All the sections (AM i-A M 29) are in the Woodwardian (Sedgwick) Museum, Cambridge. All the figures, except Figs. 4 and 5, are microphotographs from the actual sections by Mr. W. Tams, Cambridge. Some of these should be examined by means of a hand lens. Figs. 4 and 5 are photographs by Mr. Tams, from drawings by Mr. E. Wilson, Cambridge. Fig. 1. Complete transverse section of a root, p.d., periderm; p.x., proto- xylem ; x 2 ., secondary xylem ; r.x., xylem of rootlet ; z., zone of thin-walled tissue, comprising phelloderm, pericycle, and phloem ; gr., groove in the periderm, x n§. Section AM 18. Fig. 2. Part of a transverse section of a root, internal to the periderm, and opposite a protoxylem-group. p.d., periderm; phg ., phellogen ; ph.d., phello- derm; p.c., pericycle; m.r., main medullary ray ; p.x. , protoxylem ; r.x., xylem of rootlet, x 75. Section A M 24. Fig. 3. Part of a transverse section of a root, internal to the periderm, and opposite one of the convexities of the secondary xylem. p.d., periderm ; p.c., pericycle ; b.z., phloem-zone ; ft 1 ., secondary phloem ; s.t., sieve-tubes ; bp., bast parenchyma ; b 1 ., primary phloem, x 75. Section AM 15. Fig. 4. Drawing of sieve-tubes as seen in a longitudinal section of the stem of Medullosa anglica. s.p., sieve-plates, x 280 approximately. Section A M 9. Fig. 5. Drawing of a sieve-tube as seen in a longitudinal section of a root of Medullosa anglica. s.p., sieve-plates, x 430 approximately. Section AM 28. Fig. 6. Complete transverse section of a root, r.l., lateral root ; gr., groove in periderm, x uf. Section AM 23. Annals of Botany W. Tama, Microphoto. ARBER.-MEDU Vol. XVII, PL XX. University Pree3, Oxford. SA ANGLICA ph.d. Annuls of Botany Vol XVII, PI. XX. W. Tams, Microphoto. University Press, Oxford. ARBE r.- medusa anglica Morphological Notes. BY Sir W. T. THISELTON-DYER, K.C.M.G., C.I.E., F.R.S., Director , Royal Botanic Gardens , Kew. With Plates XXI-XXIII. IX. A Kalanchoe Hybrid. HEN two distinct species are crossed, one would V V expect, a priori , the offspring to exhibit a c blend ’ of the parental characters. And this appears to correspond largely with experience. Thus Darwin states : ‘As a general rule, crossed offspring in the first generation are nearly inter- mediate between their parents’ (Variation of Animals and Plants, ii. 48). Such cases occur in nature, and before their real origin was understood they were regarded as intermediate species. Thus Geum intermedium stands between G. rivale and G. urbanum. But Bell Salter by crossing these two species proved it to be a hybrid. The rule is, however, by no means invariable, and Romanes, writing in 1881, remarks: e Until recently the interest attach- ing to hybridism was almost entirely of a practical nature, and arose from the fact, which is of considerable importance in horticulture, that hybrids are often found to present characters somewhat different from those of either parent or species’ (Encycl. Brit., xii. 422). Darwin states the same [Annals of Botany, Vol. XVII. No. LXVI. March, 1903.] 43 6 Thisdton-Dyer— Morphological Notes . fact : ‘ When two races or species are crossed, there is the strongest tendency to the reappearance in the offspring of long-lost characters possessed by neither parent nor immediate progenitor ’ (loc. cit., ii. 48). Though such facts are well known to cultivators and are of extreme interest, they have seldom been put on record with much exactness or in a form convenient for reference. If seemed to me, therefore, worth while to illustrate rather fully a striking case which has come under my own notice at Kew. Kalanchoe is a genus of Crassulaceae with about fifty species which has its head quarters in Africa, from which, like many types of the African flora, it has spread eastward by way of Arabia and North-west India. Kew has had the good fortune to be able to add to science and to horticulture two striking new species, both of which have been well figured in the Botanical Magazine, and can therefore be readily studied. K. flammed (B. M. 7595), so named from its brilliant orange-red flowers, was raised from seed collected in Somali- land by Mrs. Lort-Phillips and Miss Edith Cole. The flowering plant is about a foot high, with ‘ obovate or obovate- oblong, thickly fleshy, quite entire or obscurely crenulate ’ leaves. K. Bentii (B. M. 7765) was raised from seeds collected by the late Mr. Theodore Bent in the Hadramaut district of Southern Arabia. The flowering plant is about three feet high, with thickly fleshy, recurved, c dagger-shaped,’ or rather stiletto-shaped, leaves ; the flowers are white, but pinkish when unexpanded. Both species happening to be in flower together, Mr. W. Watson, the Curator of the Royal Botanic Gardens, a skilful and intrepid hybridizer, attempted to cross them. This was done both ways in June, 1900, and in each case the result was successful. The results were as remarkable as unexpected. I will briefly summarize them. Thiselton-Dyer . — Morphological Notes . 437 1. K.flctmmea ? x K.Bentii $ . About fifty seedlings were raised and grew vigorously. The middle figure of Plate XXII represents a young seedling about fifteen months old. It will be noticed that the lower and earliest leaves are intermediate, as was to be expected, between those of the two parents. They are neither flat and obovate nor simply stiletto-shaped, but are thickly fleshy and oblanceolate. Plants of the two parents of about the same age are shown on the same plate, K . flammed on the left, K. Bentii on the right. The three figures tell their own story. Very soon, however, the characters of the hybrid entirely changed. The leaves ceased to be entire, but became strongly pinnatisect with segments which were less and less flat and more and more stiletto-shaped. In these characters and in the mode of their development the whole batch of seedlings were absolutely uniform. On Plate XXIII the details of the leaf-forms of the hybrid and its two parents are shown more in detail. It is to be observed that the earliest leaves of a shoot are always more or less rudimentary. And it is well known that rudimentary structures, not being immediately adaptive, often afford evidence of ancestral influence which is afterwards obliterated. In each case in the plate the rudimentary as well as the mature forms of the leaves are shown. In the case of K. flammea (Fig. 2) there is nothing that is not merely ordinary or which calls for remark. In the hybrid (Fig. 3) the earliest leaf may be thought to recall the crenulation of K . flammea exaggerated into teeth. But no crenulation will explain the pinnatisect forms into which the dentation is after- wards developed. In the case of K. Benlii(Fig. 1 ) it occasionally, though rarely, happens that one of the rudimentary leaves is strongly two-toothed. It seems possible, therefore, that the extraordinary character of the foliage of the hybrid derives from this parent, in which it was latent. But I will pass on for the moment to the further develop- ment of the hybrid. The plants were grown on, and in their second year attained rapidly a height of about three feet, 43 8 Thiselton-Dyer . — Morphological Notes. rather less or more in individual cases. And they began to flower in May, 1903, when, therefore, about two years old. The appearance they then presented is shown in Plate XXI. This, however, gives only an imperfect idea of the singular appearance of the plants : the leaves were strictly decussate, i.e. each successive pair was set on the stem at right angles to those above and below. And the divisions were so uniform and symmetrical that they exactly corresponded when looked down upon from above. The flowering of the hybrid was looked forward to with much interest, and when it occurred was a complete surprise. The majority of the plants flowered, and in every case the colour of the flowers was a clear rosy pink, recalling the tint of those of Erythraea Centaurium. In the case of a sudden variation or ‘ break 5 of this kind it is usual for the colour of the flowers to become highly variable. But in this case it seemed absolutely uniform, and I could not persuade myself that there was any difference between one individual and another. I must confess that I was completely at a loss to explain how a bright pink could arise from a cross between an orange and a white. The explanation, however, occurred to my friend Dr. Lotsy, who, while staying at Kew, had been much interested in the hybrid. The orange colour of the flowers of K . jlammea is due to deep yellow chromoplasts immersed in a pink cell-sap. In K. Bentii both chromoplasts and cell-sap are colourless. The hybrid has inherited the white chromoplasts of one parent and the coloured cell-sap of the other. The foliage, however, exhibits in the adult plant no trace of the influence of K. jlammea. But it is widely divergent from that of K. Bentii. K. laciniata, which extends from Tropical Africa through India to Java, has deeply pinnatifid leaves with sometimes linear segments. The leaves of K. 'Schweinfurthii from Abyssinia are also similarly divided. The conclusion seems irresistible that we have in the case of the hybrid a reversion to an ancestral character which T hiselton-Dyer . — Morphologica l N otes. 439 exists elsewhere in the genus but is latent in both parents. In attempting to explain how this comes about, I cannot better the theory of Delage : ‘ II pent arriver qu’un caractere vraiment latent revienne au jour. Le croisement jette un grand trouble dans revolution de l’ceuf, par ce rapport d’innombrables gemmules inattendues ; certains caracteres normaux sont aussi contrairies dans leur developpement et des caracteres anciens se developpent a leur place ’ (Structure du Protoplasma, 580). 2. K. Bentii ? x K. flammea £ . A number of seedlings were raised which at first differed in no appreciable character from seedlings of the same age of K. Bentii as represented in Plate XXII. All were exactly alike, and exhibited at first no trace of hybrid origin. But though raised at the same time and subjected to exactly the same treatment as the reverse cross described above (which may be called K. kewensis')^ they at once showed a marked constitutional difference in the extreme slowness of their growth. When K. kewensis was three feet high, the plants of the reverse cross had only attained six inches. It is, however, interesting to note that after cultivation for two years and a half they have begun to develop the same pinnatisect leaves which are so characteristic a feature in K . kewensis . As none of the plants have yet flowered, what will happen then can only be a matter of conjecture. It is probable, however, that they will resemble those of K. kezvensis , for as Darwin observes : ‘ Hybrids raised from reciprocal crosses . . . rarely differ in external characters ’ (Origin, 6th ed., 244). It is clear that in the reciprocal crosses the influence of K. Bentii has been prepotent. This is in agreement with the facts cited from Gartner by Darwin in regard to Nicotiana (Variation of Animals and Plants, ii. 67). But K. kewensis exhibits in the most striking way a char- acter in the foliage which cannot be attributed to either parent. If I am right in attributing this to reversion, it presents a striking exception to the principle laid down by Gartner and accepted by Darwin : ‘ Reversions rarely occur 440 Thiselton-Dyer. — Morphological Notes. with hybrid plants raised from species which have not been cultivated, while with those which have been long cultivated they are of frequent occurrence. . . . Max Wichura, who worked exclusively on willows, which had not been subjected to culture, never saw an instance of reversion 5 (Darwin, loc. cit., 50). I have already quoted Darwin’s dictum that : ‘ As a general rule, crossed offspring in the first generation are nearly intermediate between their parents, but,’ he adds, ‘ the grandchildren and succeeding generations continually revert, in a greater or less degree, to one or both of their progenitors.’ It is to this fact, I suppose, that an attempt is made to give expression in what is called Mendel’s law. It would have been very interesting to have seen what would have happened to K . kewensis in succeeding generations. Unfortunately, so far every attempt to raise seedlings from it has failed. The capsules form with every promise of fertility, but only contain shrivelled rudiments of seeds. But had this been otherwise, it by no means follows that its characters would have shown any dissociation. Wichura ‘ found in opposition to Naudin that the progeny of hybrid willows retains its hybrid character’ (Romanes, loc. cit., 426). While writing these lines the important paper by De Vries (Comptes rendus, 2 Fevr., 1903, pp. 321-3) comes into my hands. It confirms the suspicion which I have long enter- tained that Mendel’s law is not of universal application. DeVries lays it down that : ‘La loi de Mendel s’applique aux caracteres dits de variete, tandis que les caracteres specifiques vrais donnent dans leurs croisements des caracteres d’hybrides constants.’ Such characters ‘ne se disjoignent pas ; ils restent les memes dans les generations successives. J’ai verifie ce fait par quatre generations d’un hybride entre les CEnothera muricata , L., et CE. biennis , L., et j’ai etudie a ce point de vue diffdrents autres hybrides, notamment dans le meme genre.’ The explanation depends probably on the principle of specific stability, on the importance of which I have else- where insisted. From this point of view a hybrid may carry Thiselton-Dyer. — Morphological Noles. 441 over the stability of its parents, though it may not necessarily do so. In other words, the resultant of the fused parental characters may be as stable as their components. But when a species is varying, i. e. producing varieties, its stability is for the time lost, and there is nothing to prevent the dissocia- tion of the fused characters and of their constituents, or their recombination in every possible way. And I am confirmed in this opinion by the statement of Bateson that there is ‘ one group of cases, definite though as yet not numerous, where we know that the Mendelian principles do not apply’ (Principles of Heredity, pp. 34, 35). The remainder of the passage is too long to quote, but may be referred to with advantage by those who are disposed to pursue a fascinating subject. Annals of Botany , Vol. XVII. PL XXL THISELTON-DYER.— KALANCHOE HYBRID, Annals of Botany, Vol. XVII. PI. XXII. THISELTON-DYER.— KALANCHOE HYBRID. Annals cf Botany Vol.XVIl PIXXIII. 1 . University Press, Oxford. TH IS ELTON - DYER.— KALANCHOE HYBRID. NOTES. DIAGNOSES SPECIERUM GENERIS JULIANIA, SCHLBCHT, „ AMERICAE TROPICAE, Auctoribus W. Dotting Hemsley et J. N. Rose. Arbores mediocres et frutices Mexici et Peruviae incolae, dioicae, adspectu Burserae specierum nonnullarum. Folia decidua, alterna, imparipinnata, in apicibus ramorum hornotinorum floriferorum conferta, foliolis oppositis diverse dentatis. Flores masculi parvi, numerosissimi, in amenta vel racemos compositos axillares gra- cillimos pendentes dispositi ; perianthium simplex, tenuissimum, 6- 8-partitum, segmentis linearibus acutissimis; stamina isomera, quam perianthii segmenta paullo breviora ; gynaecei rudimentum nullum. Flores feminei e solis pistillis constantes, saepius quatuor receptaculo fere clauso inclusi, collaterales (haud concentrici, i. e. circa axin centralem positi), duo exteriores saepissime imperfecti, abordvi. Receptacula parva, per anthesin obscura, circiter semi- pollicaria, axillaria, pedunculata, gemina singulave, erecta, apice minute paucidentata. Ovarium uniloculare, uniovulatum, stylo tri- partite e receptaculi orificio exserto. Fructus cum pedicello plano- compresso dilatato corpus indehiscens apice incrassatum deorsum alatum formans, pendulus ; ala e basi cuneata sursum sensim oblique vel aequilateraliter dilatata. Semen unicum, in fundo loculi affixum, perispermo nullo ; embryo horizontalis, radicula elongata cotyledoni- bus plano-convexis accumbente. Juliania adstringens, Schlecht. in Linnaea , vol. xvii. (1843), P* 746, Hemsl. in Hook . Ic. PL tab. 2723. Folia quoad foliolorum numerum, circumscriptionem ac magnitu- dinem valde variabilia, primum plus minusve hirsuta, demum glabre- scentia, nunc in eodem ramo omnia 3-foliolata, nunc in eodem ramo alia 3-foliolata alia 5-foliolata, interdum 5- vel 7-foliolata vel omnia 7- foliolata, cum petiole communi 2-7 poll, longa ; foliola crasse papyracea, sessilia vel brevissime petiolulata, saepius obovata vel oblanceolata, plerumque supra medium latiora et diverse crenata vel serrata, rarissime usque ad basin dentata, basi saepius cuneata, apice [Annals of Botany, Vol. XVII. No. LXVI. March, 1903.] G g 2 444 Notes . gradatim vel abrupte acuminata, obtusa, rotundata vel truncata, maxima 3 poll, longa et 2 poll, lata, sed saepius multo minora ; venae primariae costae utrinque circiter 10-12. Pedunculi fructiferi brevis- simi. Fructus pendulus, oblongus, basi cuneatus, rectus vel plus minusve obliquus, 1-2 poll, longus, tarde glabrescens. — Hypopterygium adstringens, Schlecht. in Linnaea, vol. xvii. (1843), P- 635. Amphi- pterygium adstringens , Schiede in schedula, ex Schlecht., loc. cit., p. 746. Mexico Australis : Morelos, Schiede ; alt. 5,000 ped., Pringle, n. 7,243 et 8,533 ; Rose et Hay , n. 5,341 ; Michoacan et Guerrero, Langlassd, n. 319 bis; Oaxaca, Nelson, n. 1,706 et 1,827. Juliania mollis, Hemsl. in Hook, Ic. PI. tab. 2722. Folia juvenilia omnino albido-villosa, 3- vel 5-foliolata, petiolo communi 2-5 poll, longo ; foliola crassa, sessilia vel brevissime petiolu- lata, oblonga, ovato-oblonga, elliptica, vel terminali distincte petiolulato, interdum fere orbiculari, 1-2 poll, longa, crenato- vel serrato-dentata ; venae primariae costae utrinque circiter 10, venis ultimis ob indu- mentum obscuris. Fructus ignotus. — Amphipterygium molle. Mexico Australis : Barranca de Guadalajara, Jalisco, alt. 4,000 ped., Pringle, n. 6,871. Juliania amplifolia, species nova. Folia juvenilia molliter villosula, adulta glabrescentia, 7- vel 9-folio- lata, 6-15 poll, longa, petiolo communi subtereti ; foliola mollia, papyracea, crassiuscula, brevissime petiolulata, lanceolata vel ovato- lanceolata, maxima 3^-4% poll, longa, sed saepius 2-3-pollicaria, acuminata, interdum longe acuminata, acuta vel acutissima, basi saepius rotundata, crenato-serrata vel interdum argute serrata; venae primariae numerosae. Pedunculi fructiferi -|-i poll, longi, validi. Fructus glaber vel cito glabrescens, pendulus, obliquus, if-2j poll, longus, pedicello dilatato usque ad 1 poll, diametro. — Amphipterygium amplifolium. Mexico Australis : Jalisco et Durango, Pringle , n. 5,002 ; Rose et Hough , n. 2,302, 3,735, 4,755, et 4,819. Juliania glauca, species nova. Folia glabra vel cito glabrescentia, subtus glauca, 3- vel 5-foliolata, petiolo communi gracillimo subtereti 2^-3^ poll, longo ; foliola papy- racea, nisi terminale distincte petiolulatum sessilia, lanceolata, ovato- lanceolata vel oblanceolata, sine petiolulo 1^-3 poll, longa, acuta, Notes. 445 basi saepius cuneata, margine leviter incrassata, praecipue supra medium crenulata, vel dentata ; venae primariae utrinque circiter io, venis ultimis minute reticulatis. Pedunculi fructiferi graciles, i-i-| poll, longi. Fructus pendulus, cum pedicello dilatato circum- scriptione pyriformis, 1J-2 poll, longus, glaucus. — Amphipterygium glaucum . Mexico Australis : Jilotlan, Michoacan, Lumholtz. Juliania Huaucui, A. Gray, U. S. Expl. Exped., vol. i. p. 371. Folia primum tomentosa demum, saltern supra, glabrescentia, saepissime 7-foliolata, petiolo communi gracili tereti 2-3 poll, longo; foliola mollia, papyracea, sessilia vel brevissime petiolulata, oblonga vel ovato-oblonga, maxima visa vix sesquipollicaria, saepius utrinque rotundata, crenulata ; venae primariae utrinque circiter 12, venis ultimis obscuris. Pedunculi fructiferi brevissimi. Fructus pendulus, fere linearis, 2\ poll, longus et medio 4-5 lin. latus, glaber vel glabrescens. — Amphipterygium Huaucui. Peruvia Occidentalis : A. Mathews, n. 591 ; A. J. Maclean,$me numero. Explanatory Note by W. B. H. In 1843 Dr. F. L. von Schlechtendal described a Mexican tree at considerable length (Linnaea, vol. xvii. pp. 635-8) under the name of Hypopterygium adstringens, which he subsequently (op. cit. p. 745) changed to Juliania adstringens. In the same place Schlechtendal concludes with the following statement : ‘ Epitheton adstringens a beato amico [Schiede] in schedula datum verosimiliter vim adstringentem hujus arboris indicat. Amici nomen genericum Amphipterygium , quum ala basalis tantum nec cingens adsit, rejecimus V With regard to its position in the Natural System he could only indicate remote affinities to various orders. Bentham and Hooker (Genera Plantarum, vol. i. p. 428) placed it doubtingly at the end of the Anacardiaceae. Engler (DC. Monogr. Phanerog. vol. iv. p. 500) places it in the ‘ genera ex Anacardiaceis excludenda,’ adding : ‘ Quamvis canales resiniferi 1 It is a pity that Schlechtendal did not adopt Schiede’s generic nam t Amphiptery* gium, especially as he gave publicity to it himself, because both Hypopterygium and Juliania had already been used, and his objection to Schiede’s name is unsound, the fruit being winged on both sides of the axis. As it is not improbable that ►Schiede’s name will be revived by somebody, we have repeated our names under Amphipterygium , though we should prefer retaining Juliania. Notes- 446 adsint, attamen non tales sunt quales in Anacardiaceis observantur. Planta locus systematicus, cum flores nondum cogniti sint, mihi plane dubius remanet.’ In the Botany of the Biologia Centrali-Americana, having no specimens before me, I could do no more than record the name ; and it was not till 1901, when Kew acquired specimens of the male of my J. mollis , and fruiting specimens of what I take to be the original J. adstringens , that I was able to throw a little more light on the subject by publishing (Hooker’s leones Plantarum, t. 2722 et 2723) figures of the structure, so far as the material permitted. This was done with the idea of directing attention to this singular genus, and of obtaining better specimens. It resulted in Dr. J. N. Rose, Assistant Curator of the Botanical Collections of the United States National Museum at Washington, generously offering to procure for me the privilege and advantage of examining the whole of the material belonging to that Institution, collected partly by himself, partly by Messrs. Pringle, Nelson, Lumholtz, Hay, Langlassd and Hough, together with his notes. At the present time we are engaged on a fully illustrated monograph of the genus, including an account of its anatomy and organogeny by Dr. F. E. Fritsch ; and in that we shall fully discuss its affinities. This preliminary communication, it is hoped, will bring us further material of some of the species ; more female flowers especially are wanted to enable us to complete our researches. I may add that Dr. A. Engler, of Berlin, Dr. C. Mez, of Halle, and Dr. A. Zahlbruckner, of Vienna, have failed to find any of the original specimens collected by Dr. C. J. W. Schiede, the discoverer. NOTE TO ARTICLE IN THE ANNALS OF BOTANY, VOL. XVI, NO. 03, SEPTEMBER, 1902, ON ‘THE “ SADD ” OF THE UPPER NILE.’ Grasses of the ‘ Sadd! At p. 501 of the Annals of Botany, in the article above cited, Sir William Garstin, the Under-Secretary to the Government of Egypt, in the Public Works Department, was quoted by me as saying that a specimen of the ‘ umsoof’ grass, Vossia procera, which had been sent to the British Museum, was there identified as Phragmiies com- munis. And Sir William did not mention it anywhere in his report as being one of the components of ‘Sadd’; nor, so far as I had Notes . 447 observed, did Dr. Schweinfurth mention it in the works I quoted from. But it was difficult to believe that the botanists of the British Museum could have made the mistake imputed to them. After the article was published I read Sir Harry Johnston’s 1 The Uganda Protectorate/ and found in it a description of the ‘ Sadd/ in which, after describing the growth of the Papyrus plant, he says : — ‘A long Phragmites reed, with fluffy-like plumes like the Pampas grass, grows out into the shallow water, and builds barriers into the stream which arrest the floating islands of papyrus ; or this reed may form floating islands of its own. Papyrus may prosper so much on the floating islands, composed mainly of its own roots, that these roots may reach the thickness of a man’s leg, and grow downwards twenty feet below the top of the floating islands/ Next, my attention was drawn to the paper on ‘ The Botany of the Speke and Grant Expedition/ published in the Transactions of the Linnean Society, London, vol. xxix, in which, at p. 173, was found the following : ‘ 19. Phragmites communis , Trin. ; Kunth, Enum. PI. i, 25. Arundo phragmitis, L., App. Speke’s Journ. 653. Hab., from 4 0 55' N. lat. and northward, Col. Grant ! A cosmopolitan species. ‘ [Reed in Unyoro marshes, 21st Sept. 1862. Not in flower. 8 feet high, erect, round stem, tubular between the joints. Leaves 2 spans long, 2 inches broad at their bases, stiff, smooth, not filed at their edges or on their surfaces, alternate, their bases clasp the stem, and grow regularly in one plane from the right and left sides only. * Native name and uses : “ Mataetae.” The flutes and whistles of the Waganda are made of this reed. It is said to grow as thick as the arm in Nyassa, n° S. lat., where the natives make a fence of it. . . . It extends in one great sea for 1,100 miles north of 4° 55' N. lat. — J. A. G.].’ From all this it is clear that Sir William Garstin, or the officer under him who collected the specimens of the ‘ Sadd ’ plants which were sent to the British Museum, possibly owing to absence of inflorescence, failed to distinguish between the two large grasses which probably were growing together in the same * Sadd.’ Phragmites communis is the largest grass indigenous to Britain ; and in the Dehra Dun district, and other parts of British India, it covers square miles of swampy ground, and is commonly called Elephant or Tiger grass, from its size, 15 to 20 feet in height, or, 44 8 Notes. perhaps, from affording shelter to those large animals. The vernacu- lar name in the Dehra Dun is nal It there grows on land which is submerged during floods as well as in actual swamp ; and amongst it I have seen, drawn up by its shelter and support, the fern Asplenium (Anisogonium) esculentum , Presl., 9 to 12 feet high, with a subarbor- escent candex, 6 to 12 inches high. This is not the usual habit of the fern, which in the same locality, outside the nal , grows in clumps 3 to 4 feet high. Elsewhere in the Dun, it is a hedge-and-ditch- row plant. ‘ Sudd’ v. 1 Sadd.’ As to the pronunciation and spelling of the word ‘ sudd ’ or ‘ sadd* the following is found in Sir Harry Johnston's book, vol. i. p. 149. ‘The “ Sudd ” (which should really be spelt “sadd" 1 — Schweinfurth first refers to it as “ satt " or “ sett ") is, as most untravelled people now know, an extraordinary floating vegetable obstruction which collects in the waters of these equatorial lakes and rivers where the lake surface is sheltered from rough winds, and where the current of the river is sluggish. Papyrus clumps become detached by the action of the waves or floods, and, driven by the breeze into little groups, these roots become united below the surface of the water by the accretion of water-reed and other vegetable substances, so that in time a peaty mass is formed just below the surface of the water, from which the Papyrus continues to grow as from a soil.’ (Then follows the passage quoted above, showing the! part Phragmites com- munis plays in the formation of a ‘ Sadd ’ block.) Though Sir Harry Johnston explained that the word ‘Sadd’ is Arabic, and said how it is to be pronounced, he did ]not tell us what it really means, or how it is otherwise used. But this has lately become known to people who are not acquainted with Arabic from contributions to the Press in connexion with the completion of the great dams across the Nile, which were alluded to at the outset of the article in the Annals of Botany to which this is a supplement. In a description of the works which were found necessary in the construction of the great dam at Assuan, I find mention of the considerable work ‘ done in connexion with sadds (sic) or tempo- rary dams across three out of the five deep channels which cross the 1 ‘ It is an Arabic word pronounced like the “ sud ” " in soapsuds ” ; but this is really a short sound of the vowel “ a ” in phonetic spelling.’ Notes. 449 line of the dam and carry the supply of the Nile during summer and winter. . . . The method adopted for dealing with these deep channels was to construct “sadds” across them upstream and downstream of the site of the dam ; these sadds were then made sufficiently watertight to allow of the area between them being laid dry by pumping. It was necessary to make the sadds on one side of the dam of stones so as to stand the great rush of water: these sadds were made before the great rush of water, to a level of 5 metres below high Nile, and on the north side of the dam. Thus, when the flood was subsiding, still water was easily obtained upstream of the sadd, and a sandbag sadd was commenced on the other side, so that the three channels were cleared by the end of the year/ And the word ‘ sadd/ as meaning a temporary or subsidiary dam, of earth or stone work, is found in other parts of the article now being quoted from. It seems probable the use of the word ‘ sadd/ as the name for the vegetable obstructions in the Upper Nile, was taken from the ordinary use of the word on lower parts of the river where irrigation has long been in vogue. The smallest kind of sadd is the two or three spadesful of earth with which the cultivator (in India at least) turns canal or rain water from one compartment of a field into another. The Clearing of the ‘ Sadd l A recent number of the Geographical Journal contains a paper on the ‘ Sadd’ of the White Nile, by Dr. Edward S. Crispin, explaining the method of opening up the true river bed employed by Major Matthews, who commanded the Sadd Expedition of 1 901-2. The first difficulty is to find the position of the river bed; this is done by probing, the depth suddenly increasing to 15 to 20 feet. Next, the top growth, consisting mostly of Papyrus, is cut down or burnt. Men are then landed on the cleared surface, and the sadd cut along the river banks with saws ; next transverse cuts are made, dividing the sadd into blocks convenient for the steamer to tear out. The bows of the steamer are run into the block, and the loop of a steel hawser, both ends of which are made fast to the steamer, is passed over the bows and trodden into a trench cut on the surface of the block. The steamer then goes full speed astern, men standing on the hawser to keep it in position, and after a number of trials the block is torn away and cast adrift to float downstream, where it is gradually disintegrated. H h 450 Notes. Plants allied to the Ambatch. From The Botany of the Speke and Grant Expedition ; Trans. Linn. Soc. vol. xxix, p. 58, the following may be taken : — 4 36. sEschynomene Schimperi , Hochst., in Hb. Schimp. Abyss. No. 202; A. Rich. FI. Abyss, i. 202; Baker in FI. Trop. Africa, ii. 146. ‘ Hab . By the Nile, Nov. 1862, Col. Grant. This is a form of the Abyssinian plant, from which it may possibly prove distinct when more ample material shall have been obtained. [. . . ‘A wide-spreading branched tree, 20 feet high, in or by water at Unyoro, with the Papyrus. . . . The wood is white, and streaked with black longitudinally. It is so remarkable for lightness that I measured a log \\ feet long and 15 inches in mean circumference, and it weighed only pounds. It is a most useful wood to the inhabitants, as they make floats, levers for carrying their loads, blocks to cut upon, bolts for their doorways ; and for shields no wood can equal it for toughness and lightness, two qualities requisite in the shield of the Uganda people. It would make admirable sun hats. — J. A. G.] ‘37. PE. indica , Linn.; DC., Prod. ii. 320; Baker in FI. Trop. Africa, ii. 167; Wight Ic. t. 405. l Hab. Unyoro, Sept. 1862, Col. Grant! Widely spread in Trop. Africa and Asia. [‘ Native name “ m’neenge ” (Zanzibar). Plentiful everywhere : at 5 0 S. lat. ; in the dry season (September) its dead stem was prostrate on the dried mud ; but at 2 0 N. lat., in the same month it was in leaf and fruit. Though only growing straight to 6 or 7 feet high, the thickest part of the stem measures large in proportion, 16 inches in circumference. — J. A. G/] C. W. HOPE. The Ovules of the older Gymnosperms L BY F. W. OLIVER. With Plate XXIV and a Figure in the Text. T HE seeds of most recent Conifers are fully siphono- gamous, and their organization exhibits an adaptation in complete harmony with this type of fertilization — the most perfect that has been evolved by aerial plants. But if there is any conclusion in phylogeny on which we may con- fidently rely, it is that the method of fertilization by pollen- tubes has been evolved from zoidiogamy, the type of fertiliza- tion characteristic of an aquatic ancestor. The discovery of motile spermatozoids in the Cycads and in Ginkgo indeed places a coping-stone on the edifice of Hofmeister’s generali- zations. The pollen-tube of the Conifer affords so simple and direct a means of effecting fertilization that we recognize that an ovule of relatively simple construction offers adequate facilities for the accomplishment of this process. But the instant we turn to Cycas or Ginkgo , where zoidiogamy prevails, the ovule is seen to be much more complex. Not only do we find a special chamber excavated in the apex of the nucellus for the reception of the pollen, but the ovule is also provided 1 This article is based on a lecture delivered by the writer before the Botanical Section of the British Association for the Advancement of Science at its meeting in Belfast, September, 1902. [Annals of Botany, Vol. XVII. No. LXVII. June, 1903.] 452 Oliver . — The Ovules of the older Gymnosperms. with a fairly complicated vascular system. When we pass from these most archaic of living Phanerogams to the various Gymnospermous seeds found in the palaeozoic rocks, seeds which there is every reason to believe possessed an even less specialized type of zoidiogamy than obtains in recent Cycads, we are struck with the importance and dimensions of the pollen-chamber and with the very complicated vascular system which embraces the body of the nucellus. These older seeds needed to be complex to neutralize the disadvan- tages of their ancestry. In them, whilst the macrospore is retained, the microspore still liberates spermatozoids on the nucellus. The arrangement, viewed in the light of what we find in more recent plants, may be a clumsy makeshift, but it was probably an essential link in the evolution of more perfect arrangements. The central principle of zoidiogamy is still there, hedged about by contrivances so that it may be carried out, independent of chance water-supply, by land- growing plants. With the appearance of siphonogamy these contrivances became obsolete, and the modern ovule is a reduced and comparatively simple structure from which traces of the ancestral history have in large degree vanished. The object of the present paper is to draw attention to the details of some of these older seeds, and to trace the modifications that seem to have occurred pari passu with the evolution of more perfect methods in the transportation of the male cells. And in so doing it is hardly possible to ignore certain other changes that have taken place in the structure of the ovule, changes involving an enlargement of its functions so that it has become as well a temporary resting-place or brood-chamber for the embryo. The dis- cussion in the following pages will include a consideration (i) of the ordinary palaeozoic types of seed so well repre- sented in the French permo-carboniferous and described by Brongniart and Renault ; (2) of Lageno stoma, a peculiar type found in the lower coal-measures of Lancashire and York- shire, and standing somewhat apart from the French palaeozoic seeds ; (3) of recent Cycads ; and (4) of Torreya . a remark- Oliver. — 'The Ovules of the older Gymnosperms. 453 able genus of Taxaceae, which though siphonogamous yet appears to retain marked traces of those contrivances which usually became obsolete when siphonogamy appeared. Finally we can hardly close this article without some allusion to such elementary seed-like structures as have been described, with a view to linking up the Seed Plants with the true Pteri- dophytes. But in this department, though facts that will be of the greatest value hereafter have already come to light, some time must elapse before we are able to realize step by step the manner of origination of the earliest seeds. 1. Ordinary Palaeozoic Seed Types. These in their simplest form are represented by Stephano - spermum 1 , a small unassigned seed some 10 mm. in length, 5 mm. in diameter, and circular in transverse section. This seed may be taken as the type of a group of radially sym- metrical seeds— many with ridges and other excrescences often fantastic in character. For convenience all such forms were ranged together provisionally by Brongniart, and for the sake of easy reference may be termed the Radiospermeae (= Brongniart ’s Group B) 2 , in contradistinction to the flattened seeds or Platyspermeae ( = Brongniart’s Group A) of which a few are known to belong to the Cordaiteae. The members of these two provisional groups differ in other respects than in their form. Whilst the Radiospermeae, with rare exceptions 3 , possessed a bony integument only, the Platyspermeae were in all cases provided with an additional external fleshy layer, the sarcotesta. And there were further differences in the internal organization of these two groups, though they are not of such a character as to upset the broad general resemblance that embraces all these seeds. In the briefest possible manner a type from each group may now be 1 Cf. Brongniart, Les graines fossiles silicifiees, PL XVI. 2 Brongniart, loc. cit., p. 20. 3 Trigonocarpus pusillus , Brongniart, and Tripterospermum , in the sense of Brongniart. Cf. loc. cit., p. 26, footnote. These had a sarcotesta in addition to a bony scelerotesta. I 1 3 454 Oliver . — The Ovules of the older Gy mno sperms . described, Stephanospermum as a Radiosperm, Cardiocarpus as a Platysperm. Stephanospermum is a small cylindrical seed with sharply- pointed apex. It consists of a straight nucellus enclosed in a hard bony integument. The chalaza is at the base, the micropyle at the apex. Its general organization may be apprehended by reference to PI. XXIV, Fig. io. This diagram is drawn for another purpose, but if the outer light layer of the integument and the red strand which runs along its inner margin be ignored, and the entering chalazal bundle be regarded as quite simple (as it is in Fig. i), then we have an ordinary Radiosperm. A special study of Stephanosper - imim seems to show that the nucellus stands up freely within the integument, and though this is a point of some importance it is one that has been definitely ascertained in relatively few of these seeds. The apex of the nucellus is occupied by an extensive pollen-chamber which is accurately centred to the micropyle, with which its perforated apex seems to have engaged. The body of the nucellus is occupied by the macrospore and its contained prothallium. The chalazal strand of tracheides expands at the base of the nucellus into a tracheal plate, the margins of which are continued in the wall of the nucellus right up to the pollen-chamber, the floor of which is paved with tracheides. The contained macrospore is thus completely invested in a thin mantle of tracheides. This mantle is exposed in Fig. io, and is represented by a wash of red. Whilst some of the Radiosperms resembled Stephanospermum in possessing a continuous tracheal mantle, there were others in which the tracheides had become segre- gated into distinct strands 1 (as shown in the nucellus of Fig. 1). The pollen-chamber often contains a number of large pluri- cellular pollen-grains that had been sucked into it no doubt in the ordinary way. Here it would seem they underwent a 1 This was the case in Tripterospermum , Gnetopsis , Codonospermum, and Aetheotesta. In Polylophospermum , the intermediate condition of a coarse-meshed reticulum is sometimes found, perhaps the result of an enlargement of the nucellus. Oliver . — The Ovules of the older Gy mno sperms . 455 period of maturation, and in due course liberated free-swim- ming spermatozoids. It is true spermatozoids have never been certainly recognized in these seeds, but that is a matter of small importance. The apex of the nucellus of Cycas and Ginkgo is similarly organized as a pollen-chamber, and in these cases it is well known that spermatozoids were liberated. But Stephanospermum is an older seed and exhibits more primitive characters than do the Cycads. Were fertilization effected by pollen-tubes the whole structure of the seed would be a contradiction. Whether or no the discharge of spermato- zoids was accompanied by pustule-like projections from the surface of the grain is an open question. Such projections, very small in relation to the diameter of the pollen-grain, have been occasionally observed. The stage at which almost all these seeds have been preserved is that just preceding fertilization ; only occasional specimens being met with in a slightly earlier stage of development. In referring to them the term seed is usually employed, though in recent Gy mno - sperms the corresponding stage would be called an unfertilized ovule. This usage in terminology has doubtless arisen from the appearance of maturity which their integumentary tissues present, a maturity which seems to preclude all possibility of subsequent expansion. In course of evolution, probably, the time of hardening of the integument was postponed till embryonic stages had set in, so that well-marked ovular and seed phases became recognizable ; but in the palaeozoic seeds known to us such a distinction can hardly be drawn. Whatever their differences in detail, the Radiosperms agree in that the nucellus is invested in a tracheal mantle or a number of tracheal strands, which, arising from the chalazal bundle, meet below the pollen-chamber, the floor of which they seem to have paved. Nor does their function seem difficult of interpretation. It was that of a mechanism for bringing water to the pollen-chamber. This would be impor- tant during the period of pollen-maturation and vital to the transport of motile spermatozoids at fertilization. The pollen-chamber shows every indication of having been 45 6 Oliver . — The Ovules of the older Gymno sperms. excavated in the apex of the nucellus through a mucilaginous breakdown of the tissue there ; and should the watery muci- lage tend to concentrate through desiccation, fresh supplies of water would be drawn up from the tracheal system. Ulti- mately there is reason for supposing that the way to the archegonia (which lie much as in Cycas ) was cleared for the passage of the spermatozoids by a further mucilaginous breakdown in that portion of the tracheal sheath which overlaid the summit of the macrospore ; but in the tracheides outside the area of the pollen-chamber no such change is indicated. Whether it may not have happened in allied seeds that the nucellar tracheides stopped short from the first at the margin of the pollen-chamber, so that the necessity for their solution prior to fertilization did not arise, is a ques- tion difficult to answer. For it must be borne in mind that it would be difficult to discriminate between such a case, and one in which the tracheides had been locally absorbed. That is, of course, unless the state of preservation were remarkably good and the appropriate developmental stages forthcoming. As regards the number of pollen- grains usually present in a pollen-chamber, it is impossible to speak other than broadly in consequence of the fact that even when a series of sections is obtained there is a considerable loss as a result of cutting and grinding. In the case of Stephanospermum , from twelve to twenty does not seem too generous an estimate ; and if each of the twenty cells or so of which each pollen-grain con- sists be regarded as producing a single spermatozoid, that would allow from 240 to 400 of the latter. The distance to be traversed in the passage from the pollen-grain to the archegonium varies in this seed from .5 to *85 mm. It will have been gathered from the foregoing that whilst the problem of water-supply in relation to free-swimming spermatozoids stood on a satisfactory footing, there still re- mained room for advance in the direction of greater precision in the mechanism as a whole. We still appear to have the promiscuous liberation of motile spermatozoids reminiscent of a heterosporous Pteridophyte. Oliver . — The Ovules of the older Gym n osper ms. 457 Turning now to the Platysperms, we may take Cardiocarpus as their type. It is characterized by its flattened, heart-like form, and by the possession of a sarcotesta. As the supply- bundle enters at the chalaza and traverses the sarcotesta, it gives off a pair of bundles which run along the inner limit of that layer to the micropyle (as in Fig. 1). The plane in which these two bundles run is the plane of flattening, generally designated the principal plane of the seed \ The main bundle continues to the base of the nucellus, where it expands into the tracheal plate. From the margins of this plate a number of nucellar strands pass off peripherally in the wall of the nucellus and extend a variable distance in the direction of the pollen-chamber. And now we come to a difficulty not infrequent in the investigation of fossil seeds, the inadequacy of the preservation. In the first place there is some uncertainty as to the extent of freedom that obtained between nucellus and integument, and secondly as to the actual extent of the nucellar vascular system. If we turn to the works of the French investigators who have described these seeds, the impression gained is that the lower part of the nucellus is fused with the testa and that the tracheal strands travel up- wards in the plane of fusion, ceasing where the nucellus becomes free. Brongniart’s figure of one of these seeds, Taxospermum Gruneri 2 , shows very clearly that the fusion in this case involved the basal fifth of the nucellus, but unfortunately the tracheides are not represented in his plate. Renault makes some allusion to the question, and speaks of the nucellar bundles reaching up to about one- third the height of the nucellus 3 . So that as far as the data are available it would seem quite probable that a certain 1 In others of the Platyspermeae the entering bundle passes unbranched to the tracheal plate, the margins of which supply the nucellus in the usual way. The bundles for the sarcotesta, however, are inserted upon the under face of the tracheal plate, and running outwards and backwards penetrate the sclerotesta and curve round into the sarcotesta. This type is only a slight modification of that figured, and the two types occur in seeds so nearly resembling one another as to have been included by Brongniart under the same genus. 2 Brongniart, loc. cit., PI. XV, Figs, i and 2. 3 B. Renault, Cours de bot. fossile, I, 1881, pp. 100-ic. 45 8 Oliver . — The Ovules of the older Gymnosperms. amount of fusion obtained amongst the Platysperms, and that the internal vascular system was restricted approximately to that zone. But it would be interesting to know, should the preservation permit of it, whether, and if so to what extent, the tracheal elements passed beyond the line of separation of nucellus and integument. For the structure of the seeds and the relations of the bundles recall in a very marked degree Cycadean characters (cf. Figs. 4 and 6). It is known that in certain Cycads (e. g. Bowenia and Stangeria 1 ) the inner system of bundles does not lie quite in the plane of fusion of nucellus and integument, but that the bundles exhibit a centri- fugal tendency and actually lie outside the arbitrary province of the nucellus, as determined by the downward continuation of the plane of separation of the free regions of nucellus and integument. Renault has noticed this centrifugal tendency in Brongniart’s seed Cardiocarpus Angus todunensis, and in view of this point of contact with certain Cycads he has founded the new genus Cycadinocarpus for its reception 2 . In other respects, too, the Platysperms exhibit Cycadean features, among which may be mentioned the relatively small pollen-chamber as compared with the Radiosperms, whilst often, as W. H. Lang has pointed out, the cells of the beak of the nucellus are thickened in a corresponding manner 3 . The pollen in the pollen-chambers of these seeds is generally smaller in size than the elliptical multicellular pollen so frequently associated with the Radiosperms. Here, too, there is an internal cell-group, but it by no means fills the entire grain. That it was antheridial in nature, as suggested by D. H. Scott 4 , rather than a vegetative prothallium, seems very probable. Whether spermatozoids were liberated directly from these pollen-grains, as has been suggested in the case of Stephanospermum , or whether they were led part of the way to the archegonia in tubes, as in recent Cycads, is a question 1 I am indebted to Dr. W. H. Lang for much information concerning these and other Cycadean ovules. 2 Flore fossile d’Autun et d’ISpinac, pt. ii, p. 385. 3 W. H. Lang, Annals of Botany, vol. xiv, p. 286. 4 D. H. Scott, Studies in Fossil Botany, 1900, p. 436. Oliver . — The Ovules of the older Gy nmo sperms. 459 that cannot be considered, owing to the lack of data. It is just possible, of course, in view of the distinctly Cycadean tendencies of the Cordaitean seeds themselves, that this parallelism also involved the pollen ; or, on the other hand, as D. H. Scott points out, the pollen-grains of Cordaites may have been a stage nearer the Cryptogamic microspore than those of Cycas or Ginkgo h From what has been stated above it is evident that the Platyspermic (or Cordaitean) seeds must be carefully discrimi- nated from the Radiospermic. The former show a marked approach to a parallelism with the ovules of recent Cycads, whilst the latter appear to exhibit more general and perhaps more primitive characters. That all these seeds belonged to plants of common * if remote ancestry there can be little reasonable doubt in view of their general striking unity of organization. The types of seed possessed by these remote ancestors may have to a certain extent combined the characters of both these groups, as in the hypothetical Figures 1 and 10. Actually the seeds represented in these figures are symmetrical about a principal plane, but that modification has been intro- duced for purposes of comparison with certain recent seeds ; here, regarding them as possible ancestral forms of the Radio- spermeae and Platyspermeae, this implied flattening may be disregarded. 2. Lagenostoma. This seed, belonging to the lower coal-measures, was in point of time considerably earlier than Brongniart’s seeds from the French permo-carboniferous. Nevertheless, it shows marked and unusual peculiarities, and evidently stands some- what apart from the generality of palaeozoic seeds. In consequence, it seems fitting to treat it apart from the other seeds of the primary rocks, though regarding it as a type analogous to the Cycad in certain respects. The general organization of this seed is known from Wil- 1 D. H. Scott, loc. cit., p. 435. 460 Oliver . — The Ovules of the older Gymnosperms. liamson’s description of Lagenostoma ovoides h It is a small seed, some 4J mm. x %\ mm., circular in transverse section, and belonging to the type with adnate integument and nucellus. These parts are free from one another in the region of the pollen- chamber alone, about one-fifth the whole length of the seed- The relations of the parts in median longitudinal section are given diagrammatically in Fig. 9. The free apex of the nucellus, the ‘ lagenostome * of Williamson, is transformed into a pollen-chamber (Fig. 9, pc.). The nucellar epidermis persists as the wall of the chamber {pew.), the cavity of which has arisen by the separation of the central tissue from the wall. This central mass stands up freely from the floor as a cone of tissue ( cc .), so that the actual pollen-chamber, in which nu- merous pollen-grains frequently occur, is a crevice that may be likened to the true cavity of a ‘ Sachsian bell-jar.’ Surrounding the pollen-chamber is the very complicated integument, of which only the general relations are seen in the longitudinal section. In the transverse section of the apex of the seed, represented in the adjacent text-figure, the integument is seen to consist of an outer zone t., which is circular in transverse section, and an inner zone of (in the case figured) nine symmetrically disposed chambers which are separated from one another by strong radial plates. The internal angle of each chamber is convex, and their internal containing-walls form collectively a fluted membrane (c.) which was termed by Williamson the 4 canopy.’ The convexities of the canopy engage with corresponding concavities of the pollen-chamber wall. The space g . between the two mem- branes is the natural gap between nucellus and integument. The chambers which formed the canopy were occupied by soft parenchyma, whilst in each chamber a single tracheal strand ran longitudinally ( v ., Text-fig. 20). These strands were direct prolongations of the system of strands which di- verged from the entering supply-bundle of the chalaza, and ran up near the plane of ‘ fusion ’ of nucellus and integument 1 On the Organization of the Fossil Plants of the Coal-Measures, pt. viii, Phil. Trans. 1877, pp. 233-43, and Figs. 53-75. Oliver . — The Ovules of the older Gymnosperms. 461 (Fig. 9). The seed appears to lack a sarcotesta, and so far agrees with such members of the Radiospermeae as had distinct nucellar bundles. But the chambered apex of the seed with its vascular prolongations constitutes an organ unique amongst the palaeozoic seeds. The peculiar form of the pollen-chamber is correlated with the distribution of the archegonia, which seem to have occupied a ring immediately beneath the bell-shaped crevice (as suggested in Fig. 9). Fig. 20. — Transverse section ot Lagenostoma cut near the apex at v in Fig. 9 (PI. XXIV). The section traverses the pollen-chamber/^., enclosed in its wall pew . ; cc. is the central cone of nucellar tissue ; t. testa ; c ., the fluted ‘canopy’; v., vascular strands running in the chambers of the ‘ canopy’; g., chink between canopy and pollen-chamber wall. x 30 (From the ‘ New Phytologist.’) Compared with the ordinary palaeozoic type of seed, Lagenostoma seems peculiar in the lack of tracheal supply beneath its pollen-chamber. Assuming that this deficiency is real and not due to imperfect preservation, there are at least two possibilities open in respect of the course of events in the pollen-chamber. The pollen-grains themselves, though 462 Oliver . — The Ovules of the older Gymnosperms. not yet fully studied, seem to have been filled with a tissue as in the well-known case of Stephanospermum 1 . They would in that case belong to the old type, and it may reasonably be suspected that they liberated spermatozoids. A consideration of the relations of this pollen-chamber at one time suggested that perhaps the pollen-grains formed haustorial attachments in the central cone of parenchyma and behaved somewhat as in Cycads, but the best specimens give no support to such an hypothesis, which must accordingly be rejected. Another view is based on the peculiar relations of the micropyle. As shown in Fig. 9, the micropyle is plugged by the summit of the nucellus, so much so that if this condition obtained at pollination the intervention of a micropyle would be dispensed with. If, now, there were any reason for believing that the apices of the chambers of the canopy were porous, if the tracheal strands could be supposed to end in hydathodes, all the essentials of a contrivance for supplying the pollen- chamber with water would be present. For whatever may have been the natural position of the seed (pendent or erect), a drop of water at the summit would inevitably be drawn into the narrow crevice of the pollen-chamber. The specimens convey the impression that the wall of the pollen-chamber was so tightly jammed in the micropyle as to exclude the siphoning of water into the spacer*. (Fig. 9) which lies between the canopy and the true pollen-chamber. As yet no sections are available which fully elucidate the mode in which the strands end at the micropyle ; but the preservation of this seed occasionally reaches such a high standard of excellence as to encourage the hope that such sections may eventually be forthcoming. Sufficient has been said regarding Lageno stoma to show that whilst it resembled Cycads in the considerable area of ‘ fusion ’ that obtains between the nucellus and testa, as well as in the presence of vascular strands in the plane of ‘ fusion,’ it is yet marked by peculiarities all its own. The confined form of the pollen-chamber marks an advance in precision on the open type of the ordinary palaeozoic seed, 1 Cf. Renault, Cours de bot. fossile, IV, PI. XXI, p. 99. Oliver . — The Ovztles of the older Gy mno sperms. 463 whilst in the canopy we seem to have a structure whose homology, like its function, is at present obscure. It would be premature to enter into any discussion as to the relations of this seed until its structure has been more fully elucidated. 3. Cycads. The ovule in this group offers so general an agreement with the usual palaeozoic type that any view of its affinities seems inadmissible which excludes relationship with the Radio- spermeae and Platyspermeae. The main difference is found in the fact that only at the apex are nucellus and integument free from one another. The pollen on its entry into the pollen-chamber becomes rooted by haustorial attachments in the wall of the chamber. It thus obtains adequate nourishment for its further develop- ment. In due course the pollen-grain extremities of these tubes undergo a stretching, so that the sperm-cells are brought down close to the necks of the archegonia. Here they are liberated, the necessary fluid for their swimming being sup- plied, in some cases at any rate, from the tubes as they burst k The distribution of the vascular system in the Cycadean ovule demands some consideration. Though the general plan is fundamentally the same throughout the group, there is considerable variation in detail in the different genera and even species. The case here set forth is that of Cycas Rumphii 2 (Figs. 4-8). The common supply-bundle gives off the branches to the integument before its actual entry into the ovule (Fig. 4 sb.), and then continues its course into the chalaza ( cb .). The integumental bundles are two in number and run in the sarcotesta undivided to the micropyle. The plane in which they run is known as the principal plane of the ovule. Before these integumental bundles pass beyond the chalazal region, however, each gives off an internal 1 H. J. Webber, Spermatogenesis and fecundation of Zamia, 1901. 3 I have to acknowledge much assistance from Miss Edith Chick, in the study of the structure of Cycadean ovules. 464 Oliver . — The Ovules of the older Gymnosperms. bundle ( hb\ ) which constitutes the nucellar supply in the regions adjacent to the principal plane. The nucellar ring of bundles is completed by the strands which originate from the central chalazal bundle. Fig. 4 is a section in the principal plane, Fig. 5, in the plane at right angles to the principal plane. The nucellus is thus invested in a system of bundles of double origin. One portion, and here the chief portion, of the bundles has its origin in the central chalazal cord ; whilst on the flanks, i. e. adjacent to the principal plane, a limited number of bundles is supplied from the strands of the integument. These relations are fully exposed in Fig. 6, which represents an ovule with the integument of one side dissected away so that the nucellar bundles are laid bare. The principal plane is indicated by the line /., conse- quently the relations shown by this dissection are those that would obtain if Fig. 5 be imagined built up into a solid figure and not merely a section. For the sake of clearness the main supply-bundle (sb.) and the two groups of nucellar bundles which arise directly from its continuation are drawn in black in this figure (the same holds in Figs. 7 and 8), whilst those nucellar bundles that take their origin from the integu- mental bundle on the exposed side are coloured red. The point of insertion of the integumental bundle on the main supply-bundle is shown as a red spot (lb.), but the intervening connexions with the nucellar bundles nb' . (readily understood from Fig. 4) are for obvious reasons not represented. The transverse sections cut at the levels A and B (in Fig. 6) show that the series of bundles from the central cord (black in Figs. 8 and 7) reach nearer the pollen-chamber than those inserted upon the integumentary bundles (red in those Figs.). This disparity in the upward extension of the nucellar bundles is correlated with the fact that the groove between the free nucellus and integument extends considerably further down in the neighbourhood of the principal plane than it does elsewhere (cf. Fig. 6). The significance of this peculiarity in the course of the groove (which recurs also in Torreya , , see p. 468) is obscure. Oliver . — The Ovules of the older Gymno sperms. 465 The arrangement of the strands in Cycas Rumphii is in close agreement with that shown by Warming to exist in Cycas circinalis 1 . But many other different types obtain according to the manner of joining up of the vascular strands at the chalaza. Thus in Zamia sp. (a complex case) the ovular supply is constituted from two bundles, each of which forks and joins again as they pass into the chalaza. Of these two reunited bundles, one supplies one-third of the integument and nothing more ; the other gives off two bundles which supply the remaining two-thirds of the integument, whilst its continuation breaks up, supplying two-thirds of the nucellus. The remaining one-third of the nucellar ring is derived, relatively high up, from one of the two integumental bundles which arose lower down from this same system. These varying types of chalazal branching seem consistent with the assumption that the whole of the body of the ovule, below the level at which the nucellus becomes free, is phylo-' genetically younger than its apical parts — that between the original ovule and its insertion a new region has been inter- calated. This suggestion is embodied in Figs. 1, 2, and 3. In Fig. 1 is shown the conjectured ancestral palaeozoic type as described in the first section, but so far modified by the assumption of a plane of symmetry as to bring it in touch with a Cycadean ovule such as that of C. Rumphii . In Fig. 2 the possible mode of intercalation of a new zone is indicated by the broken lines (included under the bracket b .), all the structures of nucellus and integument being continued across this new zone. As the zone of stretching lies below the insertion of the nucellus, the gap between nucellus and integu- ment finds no place in the new insertion. For the rest, how- ever, it is a mere extension of the tissues of integument and nucellus. An ideal case is represented in Fig. 2, perhaps never realized, in which the bundles are all connected at the chalaza exactly as in the palaeozoic type (Fig. 1). With the basal extension of the ovule fresh distributions of the 1 E. Warming, Recherches et remarques sur les Cycadees, 1877, P* 21 and PI. Ill, Figs. 6-12, 4 66 Oliver . — Z&? Ovules of the older Gy mno sperms. bundles could take place, and in an instance like Cycas Rumphii it is readily comprehensible that a certain number of the nucellar strands in the neighbourhood of the principal plane might have joined up with the integumental bundles as shown in Fig. 3. In other cases, as in Stangeria where nucellar and integumental bundles appear to arise in common, the whole of the nucellar bundles may have undergone this change of insertion ; whilst even in the complex Zamia it is possible to understand that the growing basal zone gave opportunity for the production of the anastomoses outlined above. But of course no attempt is made to offer a special explanation for each several case— that is out of the question. The suggestion made is a general inference from the facts, and its validity must depend on the degree in which it renders the structure of the Cycad ovules more intelligible than it was before. The main significance of this intercalation is probably nutritive — the provision of a suitable brood-chamber for the nursing of the embryo. The other point that calls for notice here is the retreat of the nucellar bundles from the pollen-chamber (of. Figs. 1, 2, and 3). In the Cycadean ovule they are no longer needed so urgently as in the palaeozoic seeds (especially the Radio- sperms), mainly because the pollen effects haustorial attach- ments in the nucellar tissues, obtaining thus the water required in further development, and even for the swimming of the spermatozoids in their brief journey to the archegonium. In part, perhaps, the broader surface of continuity of the tissues of nucellus and integument (a result of the basal extension) would be a contributing factor in the decline of the water-excreting tracheal contrivance which was so conspicuous in palaeozoic times. 4. Torreya. The facts of the vascular anatomy in the seeds of this genus of Taxaceae are peculiar and isolated among recent plants, and in the light of palaeozoic seeds would mark it as an archaic type even were Torreya not recognized as far back as Oliver . — The Ovules of the older Gymnosperms . 467 the lower Cretaceous. In the apparent retention of old features it exceeds either Taxus or Cephalotaxus , and its inaccessibility as an object of detailed investigation has left a regrettable lacuna in our knowledge of the Taxaceae. Whilst all details are reserved for treatment in a special memoir 1 , certain of the facts of its ovular morphology may be outlined here. Already in the winter buds the rudiments of nucellus and integument are discernible. By the beginning of May the latter overtops the former. Towards the end of this month basal stretching ensues, so that nucellus and integument are raised up slightly from the enclosing scales. From this inter- calated zone a circular cushion projects, this is the future arillus. At the beginning of June the buds open, exposing the micropyles, and pollen is collected in the usual way. The arillus now grows rapidly and meets above the micropyle before the end of July. By this time pollen-tubes have developed, and these reach the embryo-sac early in Sep- tember. Before the winter resting-period pro-embryos have been formed in the archegonia, whilst the base of the young seed has undergone considerable expansion. This expansion and further embryonic development is continued in the follow- ing spring. The most striking phase is that shown in July, when enormous expansion of the seed-base is manifested. This is followed by the differentiation of the stone, and by the autumn the drupe-like seed ripens and falls. During this second year a marked rumination of the endosperm develops, but this feature need not be described here. The vascular system, indicated in the first year by strands of desmogen, undergoes no marked degree of differentiation till the approach of seed-ripening. Its distribution is indicated in red in Fig. 13. This diagram is a longitudinal section of a ripening seed cut in the principal plane, but the central light- red area must be regarded as convex as it represents the exposed surface of the nucellus. At the top of the figure 1 For some time I have, in conjunction with Miss Edith Chick, been occupied upon an investigation of this genus, and it is with her sanction that I am enabled to utilize some of our results here. K k 468 Oliver . — The Ovules of the older Gymnosperms . are seen the free arillus (a.) and integument (i.) covering the free portion of the nucellus. The wall of the nucellus is thin, and the contained embryo-sac and endosperm are continued towards the base of the seed, as also are the arillus and integu- ment. Two bundles enter the seed at the base, and whilst each may divide into two or more branches 1 in passing upwards, these branches unite again below the level at which arillus and integument are free from one another in the principal plane of the seed (/.). At this point the central portion of the reunited bundle dips suddenly inwards, penetrating the stony layer at a special shield-like area. The two shield-like areas, right and left of and a little below the micropyle, form characteristic marks on the stone of the ripe seed when stripped of its fleshy arillus. The view of the stone in Fig. 13 shows one of these shields with the foramen (a dot) perforating it. The crescent-shaped area at the top of the seed, often covered by a thin translucent membrane, represents the outer surface of the integument where it is free from the arillus. It is noticeable that this area attains its greatest downward extension in the plane at right angles to the principal plane, whilst in the principal plane (p.) (i. e. the one which traverses the foramina) it is much narrower. Identical relations obtain between nucellus and integument. After its passage through the stony layer of the integu- ment, and as it traverses the soft tissue which lies between the internal aperture of the foramen and the base of the groove between nucellus and integument, the tracheal strand forks, the branches turning sharply away from the principal plane of the seed. These branches direct their course towards the groove between the nucellus and integument, striking the furrow of the groove a little below its highest point. These relations are somewhat elucidated in Fig. 14, a nearly trans- verse section across the seed at the level of the foramina. Outside is the arillus, then the stone (shaded dark) with a lining of soft parenchyma. The bridge which traverses the figure vertically is the nucellus joined to the integument above 1 This branching is very marked in T. nucifera. Oliver . — The Ovules of the older Gym no sperms. 469 and below. The semicircular gaps (g.) on either side owe their existence to the fact that the nucellus is not at this level wholly merged in the integument. The bundle (red) is seen (below) traversing a foramen. The subsequent forking of the strand and the direction taken by its two branches are shown as though happening in one plane. On the other side (above) the section is so drawn as to show what happens at a slightly lower level. The integumental bundle is cut below the foramen of that side, whilst within the stone the descending branches of the strand that has penetrated the foramen (in a higher plane) are represented as red dots ( x ) in contact with the furrow between nucellus and integument. It has been explained that the groove corresponding to the line of separation of nucellus and integument is highest opposite the foramen, lowest in the plane at right angles to the principal plane k Here in the nearly ripe seed the bundle seems to lose itself in the curious hypoderm of the nucellus. Though the bundle at this stage cannot be traced further, in a younger seed (May of the second year), when only desmogen is present and tracheides are as yet not differentiated in the upper part of the seed, the desmogen-strands may be traced close to the angle of the groove right across till they meet the correspond- ing branches from the opposite side. The course followed by these desmogen-strands may be compared to that of the side ropes of a hammock, the two poles from which the hammock is suspended standing for the two main bundles of the seed which run outside the stone. In other words the strands from the foramina encircle the base of the free apex of the nucel- lus (cf. Fig. 12, the horizontal red line passing across). But true lignified tracheides do not seem to differentiate in these strands much beyond the point of forking of the primary strand, i. e. only quite a short distance within the interior aperture of the foramen. And in development differentiation comes late in the region of the foramen — coinciding with the hardening of the stone. As the summer advances there comes a period when tracheides are well shown in the bundle 1 In Cycas this groove dips in the principal plane, see Fig. 6. K k 2 470 Oliver , — The Ovules of the older Gymnosperms. outside the foramen, but it was only by the middle of August of the second year that these elements could be recognized in the actual foramen and continuing to the place of forking. A seed freshly picked at this stage and stood with its cut base in a watery solution of eosin sucked up the eosin by its xylem, and the pigment was drawn right through the foramina and a little distance further, i. e. up to the limit of differentiation of tracheides. It has been stated that the desmogen-strands run right across from one foramen to the other, encircling the base of the free nucellus, but in the nearly ripe seed they can no longer be traced all the way. Running in the hypoderm of the nucellus in the angle of the groove between nucellus and integument they become merged in the peculiar hypoderm of the nucellus which becomes prominent In July. This tissue consists of large, thick-walled, mucilaginous, pitted cells of remarkable appearance which first arise in the nucellus ad- jacent to the trough, but ultimately appear in the downward continuation of the nucellus, everywhere enclosing the pro- thallium in a continuous sheath or mantle. This layer is very characteristic, and its protoplasm becomes filled with oily granules. Its actual signification is obscure without special investigation, but its appearance suggests that it serves in some way as a go-between in respect of food that is being transferred from the green assimilating layer of the arillus to the prothallium. Perhaps it may be termed provisionally a £ digestive layer.’ It is in this layer that the strands from the foramina become lost. Indeed as a strand is followed from the forking-place the tracheides slowly die out and large mucilage cells begin, the impression gained from a study of these transition regions being that the mucilage cells and tracheides mutually exclude one another — that they are pro- duced from identical structures. For the completion of this brief account of the vascular system of the seed in Torreya one point remains to be added. It was stated at p. 468 that only the central portion of the reunited bundle turned sharply inwards and traversed the Oliver. — - The Ovules of the older Gymnosperms . 471 foramen (cf. Fig. 12, /.). The flanks continue their course for an appreciable distance in the pulp outside the stone, and end in a mass of transfusion-tracheides at a point a little below the level at which the arillus becomes free from the integument (Fig. 12, t.). The remarkable course of the bundles shown in this seed suggests a comparison with that found in Cycads and the palaeozoic seeds. At first sight Torreya seems so different that such a comparison must be vain. But bearing in mind the conclusion reached in the section dealing with the Cycads, as to the probability of the lower part of the seed being phylogenetically younger than the apex where nucellus and integument are free, and applying the same principle to Torreya, it seems possible to describe the latter in terms of the palaeozoic seed. For the purposes of this elucidation it is convenient to start with a form slightly modified from the supposed ancestral palaeozoic seed as in Fig. 10, a form differing from the type (Fig. 1) in that, instead of a single supply-bundle entering at the chalaza, we assume that there is a pair. Such a seed is shown cut longitudinally in the principal plane in Fig. 10. It resembles that given as the starting-point of Cycas in all other respects, except that the nucellar investment of tracheides is rendered as a continuous mantle and not as discrete bundles. (The red shade over the nucellus is to be regarded as representing the surface of the nucellus covered with its tracheal mantle.) From such a type Torreya may be derived by supposing that, at the time when a basal stretching of the ovule set in, this was accompanied by a marked rotation of the bundles which immediately connected with the tracheal plate at the base of the nucellus, so that one was carried some 8o° to the right and the other a similar amount to the left. This process is sufficiently represented in the transitional Fig. n, where the intercalated zone (under the bracket b.) is drawn in broken lines. It may be said that a marked feature of the evolution of this seed was the transverse expansion of the inner part of the chalaza which accompanied the general basal extension. 47 2 * * Oliver . — The Ovules of the older Gy mno sperms . Concurrently the embryo-sac has extended down (as repre- sented by arrows in Fig. n) and occupied all the available space. To interpret the facts literally the tracheal plate (at the base of the nucellus in Fig. io) has become stretched and split into a ring, and the embryo-sac has obtained an outle by extending right through this ring (Fig. n). In the seed of Torreya the tracheal plate may be still represented by the desmogen-strands which appear in development reaching from one foramen to the other (Fig. 12). Here then we have a seed in which the stone ends blindly below, and the water- supply for the nucellus is brought up round the outside and led through the foramina to the base of the free apex. These two foramina represent the ancestral chalaza, which by a strange evolutionary freak now finds itself close to the apex of the orthotropous seed 1 ! As for the integumental bundles of the ancestral type, these have dwindled down in Torreya and are represented by the spurs t. (Fig. 12). Finally, there is a temptation to wonder whether the peculiar ‘ digestive layer 5 of the nucellus which invests the embryo-sac may not be the palaeozoic tracheal mantle modi- fied to meet present requirements. Its pitted, mucilaginous character indicates that it probably performs some transfusion function in connexion with the water supplied by the tracheal strands which penetrate the foramina, whilst the nature of its contents suggests that it also plays a part in some metabolic process. Though the surface of the nucellus is coloured red in Fig. 12, thus emphasizing this view, the suggestion is ne- cessarily of the most tentative character. From what has been written it would seem possible to derive the very dissimilar seeds of a Cycad and Torreya from something approximately identical with the supposed ancestral 1 The actual relations of base and apex in the seed of Torreya , as well as some matters of minor detail, would appear to have been misapprehended by former writers. Cf. C. E. Bertrand, Ann. des sciences nat., Bot., 6® ser., tom. vii, pp. 72, 76, and PI. XI, Figs, i— 6 ; also Bull. Soc. Bot. de France, 18S3, p. 293. The same assertions appear in Renault’s Cours de bot. fossile, IV, 1885, p. 77. Oliver. — The Ovules of the older Gymnoperms . 473 palaeozoic type. If this be true, it should be possible to realize at every stage in the evolution the factors that have led to a modification of the ancestral type or to the persistence of some of its characters. In the case of the Cycads this is beset with less difficulty. The chief factors suggested above were the attachment of the pollen-grains to the wall of the pollen-chamber by haustoria and the need for increased space for the nutrition of the embryo. In Torreya , however, the factors are less evident, though the presence of the enlarging embryo midway between the foramina just as the stone is hardening (end of July) may not be without significance (cf. Fig. 14, el). The retention of the nucellar tracheal sheath as a mucilage layer (if it be homologous with the palaeozoic mantle) may be correlated with the exiguous nature of the water-supply, whilst its possible digestive function may also have a bearing. Otherwise the interior of the seed might become prematurely isolated from water-supplies. For, being completely siphonogamous like the other Taxaceae ( Taxus and Cephalotaxus), its retention here cannot be attributed to the requirements of spermatozoids. As for the other Conifers, they have lost their nucellar vascular systems, whilst the pollen-chamber is either quite obsolete or represented by the merest pouch. The base of the ovule has, however, generally undergone a marked exten- sion. The problem of the limit of the real ovule in Gymnosperms is not a new one. Strasburger made some allusion to the question years ago 1 . In another place I have emphasized the distinction drawn between the original ovule and the phylogenetically younger intercalation by proposing the terms Archisperm and Hypo- sperm to designate these regions. The phylogenetic history of a gymnospermous ovule may be compared to the case of an island rising out of the sea which becomes an inhabited centre of activity. As the elevation continues the original island becomes a remote mountain summit, whilst the newly-won 1 Die Angiospermen und die Gymnospermen, pp. 124 and 134. 474 Oliver . — The Ovules of the older Gymnosperms . ground in its turn becomes the scene of active operations. In time the summit is little more than a land-mark, and is ultimately denuded away. Whilst the consideration of these seeds from the palaeozoic rocks, together with those of recent Cycads and Taxaceae, tends to confirm the view that is held on many hands as to their common origin, it is evident that even the oldest forms show a marked advance on the condition that probably obtained in their pteridophytic ancestors. Whilst the work of recent years has tended to carry the lower limit of the Gymnosperms deep down into the Ferns, we are still in search of fern-sporangia exhibiting a tendency or capacity for seed- like adaptation. Along the line of the Lycopodineae such structures have become known to us in Lepidocarpon , the evi- dent strobilus of a Lepidodendron bearing seed-like structures 1 . But in view of the probable Filicinean affinities of the Cycads and of the other Gymnosperms, Lepidocarpon is only of value for the moment as an analogy. It cannot be supposed that the Gymnosperms were evolved from the Lycopodinean phylum. A structure standing in the same relation to the probable fern-like ancestors of the Gymnosperms as Lepido- carpon does to the Lycopodineae has yet to be discovered. Whether the transverse section of an unidentified sporangium 2 showing a belt of tracheal elements between the sporangial wall and the mass of developing spores is likely to furnish a clue must await the identification of that sporangium. In any case the condition of vascularity in a fern-sporangium, which this specimen proves to have actually existed, may have been an important antecedent to the evolution of the vascular nucellus that played so considerable a part among the earlier Gymnosperms, and from which it may be reason- ably supposed the ordinary Coniferous type of nucellus has been derived. University College, London, January , 1903. 1 D. H. Scott, The Seed-like Fructification of Lepidocarpon. Phil. Trans., 1901, p. 291. 2 A Vascular Sporangium, The New Phvtologist, Vol. i, p. 60. Oliver . — The Ovules of the older Gy mno sperms. 475 EXPLANATION OF THE FIGURES IN PLATE XXIV. Illustrating Professor F. W. Oliver’s paper on the Ovules of Gymnosperms. In all cases red colour indicates tracheal tissues. Fig. 1. A conjectural synthetic type of seed embodying the characters of such a seed as Stepkanospermum with those of a Cardiocarpus. Fig. 2. Hypothetic stage connecting the Cycadean ovule with the palaeozoic type, b., the supposed intercalated younger zone. Fig- 3 - Ovule of Cycas Rumphii , cut in the principal plane. The dotted lines beneath the pollen -chamber indicate the shrinkage of the original nucellar strands. Fig. 4. Section of ovule of Cycas Rumphii cut in the principal plane. sb. } main supply-bundle; nb., insertion of nucellar bundles on the main strand; nb'., nucellar bundle inserted on an integumental bundle ; ib., integumental bundle ; si., stone or sclerotesta. Fig. 5. The same ovule cut in the plane at right angles to the principal plane. References as in Fig. 4. Fig. 6. Ovule of Cycas Rumphii dissected so as to show the vascular system of the nucellus. The dotted line p. indicates the position of the principal plane of the ovule. The nucellar bundles (nb'.) that arise from an integumental bundle are alone coloured red, ib ., place of insertion of integumental bundle on the main supply-bundle. AA., B.B. , heights at which the transverse sections represented in Figs. 8 and 7 respectively were cut. Other references as in Fig. 4. Figs. 7 and 8. Transverse sections of the ovule represented in Fig. 6 at the heights B and A. The red dots in the nucellar circle of bundles in Fig. 7 are those which are inserted upon the integumental bundles. They have died out at the height at which Fig. 8 is cut. Fig. 9. Diagrammatic median longitudinal section of Lagenostoma. pc pollen- chamber containing pollen-grains; pew., wall of pollen-chamber; cc., the central cone of nucellar tissue in the pollen-chamber ; g., space between pollen-chamber wall and canopy; c., canopy ; v., tracheal strand here running in a chamber of the canopy ; t., testa ; a ., archegonium. The unshaded cavity of the chambers contained a soft parenchyma ; the tissue within the shaded layer of the testa in the body of the seed was probably of the same character. Fig. 10. Median longitudinal section of palaeozoic seed type for comparison with Torreya. The light red shade on the nucellus is to indicate a continuous tracheal mantle. Beneath the nucellus is the tracheal plate (dark red), and two supply-bundles each of which originates an integumental bundle. Fig. 11. Transitional type connecting with Torreya. At b. the broken lines indicate the position of the supposed intercalated zone. The dark red horizontal stripe across the nucellus is the stretched tracheal plate, now a ring. The arrows show the downward extension of the nucellus and embryo-sac. Fig. 12. Median longitudinal section of seed of Torreya through the principal plane, a ., arillus ; i., integument becoming hardened ; it is continued as a dark shaded layer right round the seed ; /, foramen perforating sclerotesta and allowing 476 Oliver . — The Ovules of the older Gymnosperms. vascular strand to pass to the base of the nucellus ; the dark red stripe joining the two foramina represents the supposed traces of the tracheal plate; t., mass of transfusion-tracheides ; the old integumental bundles are supposed to be reduced to these spurs. Fig. 13. View of stone of Torreya Myristica stripped of its fleshy arillus. The shield with foramen (/.) is near the apex; m., micropyle ; p., principal plane, x 2. Fig. 14. Cross-section of seed of Torreya Myristica so cut as to lie in the plane of one foramen (towards the bottom of the figure) and to pass below the other. The section is consequently not quite transverse. The red X (below) is the bundle traversing the foramen and its two branches which pass right and left in the direction of the furrows of the gaps (g.) here present on the flanks between nucellus and integument. The foot of the T represents the portion of the bundle which remains outside the stone ( = t Fig. 12). On the other side of the seed the bundle is cut through a little below the foramen. The two detached red spots are the cross-sections of the strands which follow the groove. As these strands sag a good deal they can only be followed from x to y by examining a series of trans- verse sections, e., embryo ; p. prothallium ; ml., coloured pale red, represents the mucilage-layer of the nucellar wall ; i., integument, the dark shaded ring is the stone (sclerotesta), the lighter ring within it is also a part of the integument but of soft parenchyma (endotesta) ; a ., arillus. Had the section been cut a little nearer the apex, gaps would have appeared right and left between the integument and arillus. x 2. z/buijaZs of* jBotour^r Fig. 9. Vol XVII PI XXIV University Press, Oxford. OLIVER.— ON OLD GYMNOSPERMOUS S E EDS The Origin of the Archegonium \ BY BRADLEY MOORE DAVIS. With two Figures in the Text. HE gap between the Thallophytes and those groups of -L higher plants which may collectively be called the Archegoniates is perhaps the most difficult of all to bridge when one attempts to trace the evolution of the plant king- dom. The problems chiefly concern the relation of the sexual organs in the two groups, or more precisely the origin of the archegonium and antheridium of the Bryophytes. The presence of a well-defined sporophyte generation in the Bryophytes, while an important distinguishing character, gives less difficulty, because studies among the Thallophytes in recent years have indicated the possibility of a very general tendency towards the development of a sporophyte in this group. It is probably shown at low levels of the Confervales (Ulothrix ) , in the Conjugales and the Oedogoniaceae, while Coleochaete , the Rhodophyceae, and perhaps the Ascomy- cetes, present sporophyte generations that in complexity may fairly be compared with the simplest Bryophytes. But the archegonium and antheridium have no parallel in the sexual organs of the higher Thallophytes, i. e. those groups 1 Contributions from the Hull Botanical Laboratory, No, 48. [Annals of Botany, Vol. XVII. No. LXVII. June, 1903.] 478 Davis.- — The Origin of the Archegonium. which have advanced to the level of sexual evolution termed heterogamy. The sexual elements of heterogamous Algae are almost universally formed in single cells. These cells are generally called oogonia when they contain eggs, and antheridia if they produce antherozoids or sperms. Sometimes a collection of sperm-producing cells, with or without accompanying sterile tissue, is called an antheridium. This term has therefore ceased to have exact morphological value, and is applied to structures widely different in their degree of complexity, some being unicellular and some multicellular. This vagueness in terminology has led to a recent protest by Vuillemin 1 , especially with reference to the term ‘sporan- gium,’ which is now applied to any organ bearing spores, re- gardless of its structure, whether multicellular or unicellular. Vuillemin suggests a terminology that will clearly show the morphology of the reproductive organs of Thallophytes in contrast to conditions among the higher plants. He proposes the following names for unicellular reproductive organs : — Sporocyst, an unicellular structure, producing asexual spores. Gametocyst, „ „ „ gametes. Oocyst, „ „ developing eggs. Antherocyst, „ „ „ antherozoids or sperms. These unicellular structures may then all be removed from the group of multicellular reproductive organs, which will then retain the old terms of — Sporangium, a multicellular organ, producing spores. Gametangium, „ „ „ gametes. Archegonium, „ „ peculiar to higher plants, developing eggs. Antheridium, „ „ developing antherozoids or sperms. The question of terminology may seem to some a minor 1 Vuillemin, Bull. d. 1 . Soc. Bot. d. France, xlix, 16, 1902. Davis . — The Origin of the Archegonium . 479 matter, but it becomes of utmost importance when it rests on a clear morphological basis. It seems to the writer that the peculiarities of the reproductive organs of most Thallo- phytes justify a most careful consideration of the above suggestions, and he will employ the terminology throughout this paper as the best means of making clear the fundamental distinctions between the archegonium and antheridium of the Bryophytes and the reproductive organs of most Algae. There are of course no archegonia in the Thallophytes, and antheridia in the narrower use of the expression (i. e. multi- cellular organs) are only represented by such structures as are found in the Characeae, and less conspicuously in groups of sperm-producing cells occasionally found among the green and brown Algae (e. g. Oedogonium , Dictyota). Logically, the term 4 antheridium ’ should be strictly reserved for such multicellular structures as have clearly developed from a single cell whose activities produce tissues with a definite form and function. The antheridium of Chara is such an example, and the antheridia of all plants above the Thallo- phytes illustrate clearly the point. On the contrary, many so-called antheridia of Algae, especially among the Rhodo- phyceae, are simply groups of antherocysts, independent cells that happen to be associated together but are not tissues. The antheridia of Bryophytes present clearly the distinctions between the antherocyst, a single cell, and the tissue with definite form whose co-operating cells establish an organ. The method of development of the antheridium is the basis of these fundamental distinctions. A superficial cell generally begins the process by several oblique divisions, which frequently result in the differentiation of a terminal cell that plays an im- portant part in defining the form of the structure. This apical cell, if present, cuts off segments that build up the antheridium from above. If there is no clearly differentiated apical cell, the structure increases in size by various cell-divisions in its mass. Finally, periclinal walls separate a sterile layer of cells on the exterior from a central group. The latter divide by walls at right angles to one another into small cubical cells, 480 Davis . — The Origin of fhe Archegoninm . each of which develops a sperm. The antheridium is then a capsule of sterile tissue enclosing a mass of fertile cells. The archegonium presents peculiarities of form and certain structural features that obscure its fundamental agreement in structure with the antheridium, but a close study of its develop- ment makes the homology of these organs clear. The arche- gonium, like the antheridium, arises from a single superficial cell, which divides in such a manner that a growing point is generally established, sometimes with a single apical cell, sometimes terminated by a group. This growing point, acting as a whole, builds up the archegonium, which is thus a unit from its earliest inception. At maturity the archegonium is a long narrow capsule, whose outer layer of cells encloses a central group. This central mass is a line of cells, some- times numerous, running the entire length of the structure. Of these only the lower cell develops a gamete, its contents rounding off as an egg. The other cells (canal-cells) break down. Generally the cells of the central mass form a single row, but Mr. G. M. Holferty has recently found among the Mosses that there may be two or more rows of canal-cells at various levels of the archegonium, but especially near the tip. His results have not yet been published, but their bearings on the present problem are so important that I have asked the privi- lege of announcing them in advance. Such conditions are identical with certain stages in the development of the an- theridium, and establish clearly the homologies between these sexual organs. It seems almost certain that the canal-cells at one time produced gametes, and are therefore homologous with one another and also with the cell that develops the egg. The entire group, canal-cells and the egg, is homologous with the mass of sperm-producing tissue of the antheridium. The archegonium is therefore a gametangium which has passed through an evolution characterized by such extensive sterilization of the reproductive cells that finally only one gamete is formed in the structure. The sterilization was progressive from the terminal region backwards, so that Davis . — The Origin of the Archegonium. 481 the selected egg lies at the bottom of the capsule in the position most favourable for its own nourishment and for the protection and assistance offered to the young sporo- phyte. The primitive archegonium and antheridium, then, agree in all essentials of structure, and are homologous. They are both multicellular from the beginning, the form is generally de- termined by a growing point, and the final result is a sterile capsule enclosing a mass of gamete mother-cells, very nu- merous in the antheridium, but so reduced in the archegonium that only one gamete matures. It is not necessary in this discussion to consider the changes that come over the archegonium and antheridium in the higher groups of the Pteridophytes and in the Spermatophytes. The general trend is always towards the simplification and reduc- tion of cell structure until many features of the primitive organs are lost. We are not concerned with these later con- ditions, but only with the older, more generalized form of organ, best illustrated to-day among the Liverworts and Mosses. A comparison of the archegonium with the sexual organs of heterogamous Algae brings out great and fundamental differences. Chara and Coleochaete are the forms naturally considered in this connexion, because their sexual organs become invested with a cellular envelope, so that the eggs either before or after fertilization lie in a capsule. But the development of these organs shows clearly that the final struc- ture is not a unit, but a composite of several independent elements. The eggs are produced in oocysts after the method usual to Algae. The enveloping capsules are formed of inde- pendent filaments which, arising from cells below the oocysts, have absolutely no organic relation to the latter. The conditions in the Charales are further complicated by the peculiar small cells (Wendungszellen) that are cut off from the egg-cell before its maturity. The significance of these accessory cells has long been a matter of conjecture. There appears to be no reduction of the chromosomes with their 482 Davis . — The Origin of the Archegonium . development. Gotz 1 believes them to stand for the walls of a reduced archegonium, thus removing this sexual organ of the Charales from the category of the gametocyst and regard- ing it as a degenerate archegonium plus the enveloping whorl of filaments that surrounds the egg and forms the crown. Gotz calls the Charales Phycobryophytes, and does not con- sider them to be directly connected with the Algae. This is a very interesting suggestion, although objections present themselves in the complexity of the processes required to bring about the degeneration of such a well-established organ as the archegonium and its displacement by an equally elaborate envelope of filaments. It seems to the writer that the accessory cells (Wendungszellen) may be nothing more than the final and somewhat irregular expression of the vege- tative activities of a growing point that is about to become transformed into a sexual organ. In any event all botanists will probably agree with Gotz and others that the female sexual organ of the Charales is not a primitive archegonium. There seems to be, then, no sexual organ of the hetero- gamous Algae from which the gametangium (multicellular) of the Bryophytes could have arisen. We are forced to seek for clues in other groups and among other structures than these gametocysts (unicellular). The structure of the archegonium and antheridium would suggest a derivation from some multicellular organ, a sporan- gium or gametangium. But unfortunately few structures of this character are known among the Chlorophyceae, that group of Thallophytes which naturally is considered nearest to the Bryophytes. We should be forced to assume a more extensive existence of such multicellular structures in groups, now extinct, which were much nearer the main line of ascent to the Bryophytes than any surviving Algae. To what extent would we be justified in placing all the heterogamous green Algae far away from such a main line, and in recognizing a region of extinct groups with sexual 1 Gotz, Ueber die Entwickelung der Eiknospe bei den Characeen. Bot. Zeit. lvii, 1, 1899. Davis.-— The Origin of the Archegoninm. 483 organs unlike any existing Thallophytes ? The justification could only be the theoretical working-out of a very plausible series of stages in types whose previous existence, while en- tirely speculative, would do no violence to the position and arrangement of existing groups of Algae. The assemblage of plants called the Thallophytes is much better understood with the advances of recent years. Although correlative with three other branches of the plant kingdom (Bryophytes, Pteridophytes, and Spermatophytes), the Thallo- phytes are peculiar in quite lacking common morphological characters of the sort that make these assemblages of higher plants very natural groups. The bonds of union in the Thallophytes are negative characters. Its members do not have the various positive marks of the higher groups. The association of the Thallophytes together because the vegetative structure is generally undifferentiated into stem, root, and leaf, is very similar to that old grouping of several independent branches of the animal kingdom under the head Invertebrata because they lacked the character of the highest subdivision. The Thallophytes include an immensely more diverse assemblage of subclasses and orders than any other great class of plants. These groups are in certain regions so distantly related to one another that the gaps can only be bridged by assuming the previous existence of whole orders now entirely extinct or represented only by an occasional stray remnant. And the ages that brought about this frag- mentary condition, with its remarkable forward developments in various directions, have left us in the structure of the surviving forms little or no evidence of the exact steps in the process. It is necessary to state this standpoint with respect to the Thallophytes so that the reader will clearly understand the possibilities of the theory that will be discussed presently, and which perhaps demands such preliminary explanation to justify its speculations. The Chlorophyceae, as we have said, present no multi- cellular organs from which the archegonium or antheridium can be easily derived. But one region of the Thallophytes 484 Davis . — The Origin of the Archegonium. gives us a structure that may throw some light on our problem. This structure is the plurilocular sporangium, and it is found in a number of the lower groups of the Phaeo- phyceae. The lower Phaeophyceae are represented by a number of families whose vegetative structure is diverse, but which agree in having one or both of two types of re- productive organs. There is the unilocular sporangium, a sporocyst, whose products are asexual zoospores ; and there is the plurilocular sporangium whose products, likewise biciliate zoospores, are known to be sexual in many forms. The sexuality of the plurilocular sporangium, while well established in certain types, is nevertheless far from universal in the group. It is well known from studies among the Ectocarpaceae that the zoospores from plurilocular sporangia may germinate without conjugation, and the external factors that determine sexuality are in part understood. So in considering the plurilocular sporangium we are dealing with a very simple and primitive type of sexual organ. The plurilocular sporangium is plainly a modified filament or branch. It consists at first of a row of cells, but shortly most or all of these begin to divide by walls in three planes, until the space originally occupied by one large cell is divided up into very many small cubical compartments (loculi), which give the structure a curious checkerboard-like appearance. A biciliate zoospore or gamete is formed in each of these compartments. Certain cells generally remain undivided at the base of the branch, constituting a stalk ; and sometimes the tip remains sterile as a hair-like continuation of the axis. Such is the structure of the simplest plurilocular sporangium. The higher types of this organ present some important modi- fications. The sterile tip is transformed entirely into repro- ductive tissue, so that the structure has less the appearance of a modified branch and more that of a specialized reproductive organ. There is also presented in certain forms (best known from studies among the Ectocarpaceae) a wide range of variation in the size and number of the compartments. Some of the sporangia have rather large compartments, and their Davis — The Origin of the Archegonium . 485 products are well-developed zoospores, deeply coloured by the brown chromatophores. The compartments of other sporangia are much smaller, and develop minute zoospores that are sometimes almost colourless. These conditions are shown in Fig. 21, a. Between these extremes there is frequently a sporangium with medium-sized cells whose pro- ducts strike an average between the large and small zoo- spores. The large and medium-sized zoospores may germinate directly if the conditions are not favourable for sexuality. The small zoospores have been known to settle down and germinate, but the results were feeble sporelings that could not live long. When sexuality is present the conjugation is usually between the large and small zoospores. The large gametes swim much more slowly than the small, and in certain forms ( Ectocarpus siliculosus y E. secnndus, and Cut- leria) settle down as motionless cells which are fertilized by the small motile gametes. The latter have evidently reached a stage in their differentiation very similar to sperms both as to structure and behaviour. It is evident that the plurilocular sporangium was not established from the first as a gametangium, because there is such a large amount of parthenogenetic development among its products. The structure at the outset was probably asexual. But it is evident that with sex once established the evolutionary direction is along lines exactly parallel with the history, so well understood, for several divergent and independent lines of Algae. Briefly stated, we observe the tendency to differentiate the gametes as to size resulting in small male and large sluggish female cells. The latter even behave like eggs in certain forms at the time of fertilization, when they are motionless. Although the type of sexual reproduction is isogamous, because the gametes are identical in form at the time of their discharge from the gametangia, still the conditions at the moment of fertilization are physio- logically those of heterogamy. Another peculiarity of the plurilocular sporangium should L 1 2 486 Davis . — The Origin of the Archegonium. be noted, and then we shall be ready to consider it in relation to our problem of the origin of the archegonium. The zoo- spores or gametes from plurilocular sporangia escape in various ways. There is extensive dissolution of the walls forming the compartments, and the zoospores are in this manner set free. But it has been observed in some species that the zoospores make their exit from the tip of the struc- ture. It seems that the walls in the interior of the sporangium may break down more rapidly than those on the outside, so that the zoospores come to lie almost free in the interior, and are therefore able to escape from the opening first formed, which is generally at the tip. We shall now take up some speculations on the fate of such a structure as the plurilocular sporangium under certain environmental conditions and in relation to the principles of sexual evolution. We shall try to show that the archegonium and antheridium might have been derived from such a structure. It should be clearly understood that this is not stating a belief that the Phaeophyceae were the progenitors of the Bryophytes. We are using the plurilocular sporangium of the brown Algae simply as an illustrative type of a reproduc- tive organ. To relate such an organ to the archegonium and antheridium we shall probably have to assume the existence of groups of green Algae with plurilocular sporangia of which no trace is left among living forms. This point will be considered later. However, it is well to point out that a few Chlorophyceae have structures identical with the very simplest types of plurilocular sporangia, although with nothing approaching the complexities of the higher conditions. In Schizomeris Leibleinii portions of a filament, at times terminal, may become transformed into a thickened region several cells in diameter, all of which develop zoospores. And again, in Draparnaldia and some related forms the reproductive cells of lateral branches sometimes divide longitudinally to produce a branch which departs from the structure of a single row of Davis . — The Origin of the Archegonium. 487 cells, and, since the cells develop zoospores simultaneously, strikingly resembles a plurilocular sporangium. The condi- tions among the lower Ectocarpaceae, especially in Pylaiella , are no more complex than in Schizomeris ; so we have in the Chlorophyceae structures that might readily be the fore- runners of well-differentiated plurilocular sporangia. A plurilocular sporangium is subject to two sets of factors that may influence its form and structure, together with the character of the sexual cells. There are, first, the general laws underlying all sexual evolution in its advance from isogamy to heterogamy. And in addition to these developments there are the changes possible in any multicellular organ, because it is a cell-complex, and may be differentiated into tissues. A gametocyst (single cell) is by its simplicity barred from the complications possible to a gametangium. The differentiation of the gametes into eggs and sperms is readily understood along the line that we have already suggested, which is a well-known path of development, and has been travelled by many groups of Algae. We know that the gametes vary in size, and that the larger female elements are sluggish and tend to settle down before fertilization as quiescent cells, to which the male gametes are attracted. Should the sluggishness of the female gametes be intensified some of them might not be able to leave the gametangium, but would remain there as eggs, retained on the parent plant, to which the male gametes must make their way. It is not at all uncommon for zoospores of various Algae to be mechanically held within a parent sporangium and, unable to escape, to germinate there. Such habits on the part of female gametes of plurilocular sporangia would finally result in heterogamy, with the retention of the eggs within the parent gametangium. What are the possibilities of modifications in form and structure of the plurilocular sporangia themselves ? These would depend on two important factors, first the sterilization of portions of the structure, and second the differentiation of regions of exit or entrance for the gametes. Modifications 488 Davis . — The Origin of the Archegonium. of the first sort are very significant, those of the second would be readily understood in relation to them. Sterilization of reproductive tissue is a well-known tendency among plants. It results in the sacrifice of certain reproduc- tive cells or tissues, either in relation to environmental condi- tions, or through the conservation of food-material by which certain cells are favoured in their nourishment at the expense of others. The latter condition is illustrated very extensively in the asexual reproductive tissue of the sporophyte, and among sexual cells notably by the sacrifice of the nuclei in the oocysts of the Fucaceae (e.g. Pelvetia ), and during oogenesis in certain Phycomycetes (e.g. Albugo , Peronospora , &c.). It is of course a fundamental principle in oogenesis among animals. If, as seems very probable, the canal-cells in the archegonium are degenerate gamete mother-cells, this principle finds an admirable illustration, for they are sacrificed with obvious advantage to the egg at the bottom of the structure, not only for its nourishment but also in relation to the mechanics by which the neck of the archegonium is opened and the sperms brought to the egg. Sterilization of reproductive tissue in relation to environ- mental conditions implies such changes as are obviously a response to external factors. They are frequently involved at the same time with the conservation of food, but this is of secondary importance. The most powerful external factor affecting an organ is the medium in which it lies. If this be air the structure must provide itself with effective protective coverings, for the drying action of the atmosphere is perhaps the most serious difficulty with which the land plant contends. Desiccation must have been the chief danger that aquatic plants faced when they left the water, and very little advance in internal structure could have been possible until this problem was solved by the development of suitable external coverings. Now let us consider what would happen to plurilocular gametangia of aquatic Thallophytes if such forms should gradually adopt terrestrial habits. The general protection Davis . — The Origin of the Archegonium . 489 against desiccation demanded by the plant would sooner or later affect the details of structure. The plurilocular sporangia would respond to the conditions and become modified with other organs of the plant. Probably the first change would be the differentiation of an external protective tissue. This would require the sterilization of the outer layer of gamete mother-cells which would form a capsule enclosing the re- mainder of the tissue. The structure of such an organ is diagrammed in Fig. 21, b. An advance of this character would place the plurilocular sporangium in the same group of organs as the antheridium and archegonium. After such a modification of the plurilocular sporangium the more special peculiarities of the archegonium and antheridium would seem insignificant. The structure would of course all along have been under the influence of the principles that regulate the evolution of sex. The gametes might already have reached some degree of sexual differentiation ; or, if not, they would constantly tend in that direction ; and the results would eventually be heterogamy, with the continued specializa- tion of male and female organs. The female gametangium would retain its gametes as eggs, and the male would dis- charge its sperms under the proper conditions of moisture. The highest development would be attained in the female organ when, through the sterilization of the gamete mother- cells, all but one were sacrificed to the advantage of a specialized egg (see Fig. 21, c). And in this connexion we may again refer to Mr. Holferty’s unpublished observations upon the archegonium of Mosses. When the canal-cells form two or more rows at various levels in this structure, we have conditions exactly like those dia- grammed in Fig. 21, b and c. So these important stages in the evolution of the archegonium which we have assumed as necessary to the hypothesis are actually present, except of course that in the archegonium the canal-cells normally do not develop gametes \ But the evidence that the canal-cells are 1 Since the above was written, W. C. Coker has described and figured (Botanical Gazette, XXXV, 136, 1903) an archegonium with two eggs, lying one above the 490 Davis . — The Origin of the Archegonium. degenerate gamete mother-cells can hardly be stronger, apart from the actual existence of such a series of organs as we have postulated. To complete the agreement between such structures and the archegonium and antheridium we have only to understand the manner in which the terminal openings of these organs would be differentiated. These points of exit and entrance are conveniently situated, but there are probably more im- portant reasons for their selection. The apex of the pluri- locular sporangium is the situation where the gametes first mature and from which they first escape. And this would probably lead to the choice of such a point of dehiscence if the archegonium and antheridium were derived from this structure. We have, naturally, very little direct evidence bearing on such evolutionary processes as we have just discussed. But the writer can see nothing in the structure, development, or behaviour of the archegonium, antheridium, or plurilocular sporangium that offers serious objections to the hypothesis presented. The difficulties are in the absence of intermediate stages, which cannot of course be presented unless forms exist that illustrate these conditions. The value of the hypothesis lies largely in its suggestiveness for further research, but it seems to the writer to offer an explanation far more acceptable than other views. Attempts to relate the archegonium to the oocysts of heterogamous Algae do violence to the fundamental character of their organization, as was shown at the beginning of the paper. This hypothesis, which carries the origin of the archegonium much farther back in point of time, seems safe in its reasoning and thoroughly consistent with the evo- lutionary principles of sex and tissue-differentiation. To make the chief points in this paper clearer, and also as a summary, we have constructed diagrams (Fig. 21) illustrating other and each with a ventral canal-cell. It was evident that the upper egg had developed from the lowest canal-cell. Such abnormalities are to be expected, according to our theory of the archegonium. Mr. Holferty has observed similar examples. Davis . — The Origin of the Archegonium. 491 the evolutionary stages required by this theory of the origin of the archegonium and antheridium. And at the end (Fig. 22) we have arranged certain groups of Algae in relation to one another and to a problematical region of extinct forms which are supposed to have existed and been directly responsible for the Bryophytes. The families Ulothricaceae, Chaetophoraceae, and Coleo- Fig. 21. — Diagrams illustrating the possible evolution of the archegonium and antheridium from the plurilocular sporangium, a. Plurilocular sporangia, with large and small gametes discharged from the apex, after the habit found in certain Phaeophyceae (e. g. Chilionema Nathaliae l , Ectocarpus virescens 2 , &c.). b. Plurilocular gametangia of a hypothetical algal type which has adopted terrestrial habits. The outer layer of gamete mother-cells has become sterilized as a pro- tective capsule enclosing the fertile tissue. The gametes are differentiated in sex but both are still motile, c. Plurilocular gametangia of somewhat higher hypothetical forms at the level of heterogamy. Sterilization has proceeded so far in the female gametangium that only a few gametes are matured at the base of the organ, and these are eggs. d. Simple types of archegonium and antheridium. The female gametes are reduced to one, while the number of male gametes is greatly increased, and these cells are smaller and more highly specialized than in the earlier conditions. chaetaceae of the Confervales are closely related to one another and seem to constitute a line of ascent. Among the lower representatives of these families are several forms (Schizomeris, Draparnaldia , &c.) whose zoospores are pro- 1 Sauvageau, ‘ Sur quelques Myrionemac^es.’ Ann. d. Sci.Nat.,8 e ser., v, 103,1898. 2 Id., ‘ Sur r Ectocarpus virescens , Thuret.’ Jour. d. Bot., x, 17, 1896. 492 Davis . — The Origin of the Archegonhim . duced in special regions of the filaments, sometimes con- siderably thickened, which resemble the simplest types of plurilocular sporangia. The presence of such structures among the Chlorophyceae is important, since it tends to overcome the difficulties in our assumption of a region of extinct green Algae with plurilocular sporangia which we have supposed to be the ancestors of the Bryophytes. The Rhodophyceae may have arisen close to the Coleo- chaetaceae. Chaetophoraceae l Ex’tinct Chlorophyceae with \ plurilocular ' sporangia Ulothricaceae Phaeophyceae with plurilocular sporangia Protococcales Fig. 22.' — Diagram showing the position of a hypothetical group of extinct Chlorophyceae with plurilocular sporangia, supposed to be the progenitors of the Bryophytes, in relation to the algae most intimately concerned with this discussion. The lower Phaeophyceae can hardly be supposed to have given direct origin to the Bryophytes, although this is con- ceivable. They have been arranged at the side of a hypo- thetical region of extinct Chlorophyceae. The Fucales are far to one side. Their sexual organs are gametocysts, and must have had their origin from unilocular sporangia. University of Chicago, January , 1903. On the Structure of Schizaea malaccana. BY A. G. TANSLEY, M.A., Assistant Professor of Botany. AND EDITH CHICK, B.Sc., Quain Student in Botany , University College , London. With Plates XXV and XXVI and a Figure in the Text. T HE Schizaeaceae are certainly one of the most interesting families of Ferns from the point of view of their stelar anatomy. Within the limits of a very natural group of but four genera they appear to exhibit all the principal stages which recent theory has distinguished in the evolution of the stele — protostely with a solid xylem in Lygodium , and with a parenchymatous pith in Schizaea , solenostely in Anemia § Anemiorhiza , and dialystely in the majority of the species of Anemia and in Mohria. There seems at present no reason for taking any other than the simple view that these four types represent progressive stages in the evolution of the stelar system, according to the general theory of Jeffrey 1 and Gwynne-Vaughan. But in a case of this kind, where we have such a wide range of structure in a single family of but few genera, it is of importance to examine the anatomy of every 1 Professor Jeffrey, however, considers that Schizaea represents a degeneration- stage from a siphonostelic type. See ‘ The Structure of the Stem in the Pterido- phyta and Gymnosperms,’ Phil. Trans., B, 1902, [Annals of Botany, Vol. XVII. No. LX VII. June, 1903.] 494 Tansley and Chick . — On the Structure species, so as to obtain all possible evidence as to the relations of the different types of structure exhibited. The present species shows some interesting features which seem worthy of record, partly by way of supplement to Boodles excellent comparative account of the family in a recent number of this Journal 1 , and partly because they suggest a discussion of the phylogenetic problems involved 2 . The sequence of cell-divisions at the apex of the stem, so far as our rather scanty knowledge of the meristems of Ferns goes, is quite exceptional, and is a striking example of the impossibility of considering histogenetic distinctions as trust- worthy guides to the morphology of adult tissues. General Description and Sporangia. Schizaea malaccana , Baker, is a fairly well distributed species of the Malayan region. It is very common on the upper part of Mount Ophir (Johore), where our material was gathered in January, 1901. The plants commonly grew several together, with their sub-erect stems embedded in leafy liverworts or in humus. The stem is short, none of the specimens in our material attaining an inch and a half in length. It is normally unbranched, yet in two or three cases we have found a branch arising close to the apex. In one instance at least this was merely owing to the death of the apical meristem ; but in another specimen there was a regular dichotomy, one branch dichotomizing again almost imme- diately. The apical growth is probably very slow, and the tissues at the hind end of the stem die off gradually as growth proceeds. The surface of the stem is densely covered with the bases of fronds and with roots, which together form a thick matted investment, and give the stem a diameter of 3 mm. or more. The fronds are well described in the Synopsis Filicum as 1 Boodle, Anatomy of the Schizaeaceae. Ann. of Bot., June, 1901. 2 The above was written before the discovery by Mr. Boodle in Schizaea dicho- toma of similar features to those indicated. Mr. Boodle’s paper containing an account of them will be found in the present number of this Journal. of Schizaea tnalaccana . 495 £ 4-8 inches long, weak, flexuose, subterete.’ They are also said to be ‘ channelled,’ but this is probably mainly due to drying, as the transverse section of the frond is oval-oblong usually with no distinct groove, though there is sometimes a slight concavity on the morphologically upper surface. There is no differentiation into petiole and lamina, the whole length of the frond being perfectly uniform externally. The fertile fronds bear at the apex a few crowded fertile pinnae, the two rows standing out on one side parallel to one another and nearly at right angles to the axis of the frond, forming a kind of double comb (PI. XXV, Fig. 1), When ripe the pinnae frequently come to stand out on each side of the axis in one plane (Figs. 1 and 2). The sporangia are borne on the inner (morphologically lower) side of the pinnae, and lie in two acropetal rows, one on either side of the midrib of each pinna. In structure and development they correspond so closely with those of S'. Pennula as described by Prantl 1 , that it has not seemed worth while to give details. Four countings were made of the number of spores in a sporangium, and the results were 90, no, 112, 115* These come fairly close to the typical number 128, and agree well with Professor Bower’s results for the order 2 . The Anatomy of the Stem. The plan of structure of the stem in the present species is usually on a smaller scale than in the other species that have been described (S'. Pennula by Prantl 3 , S. digitata , dichotoma , and fistidosa by Boodle 4 ). The cortex, apart from leaf-bases, is only four or five to eight cells thick. It consists of rather large, not particularly thick-walled cells, which are frequently packed with starch grains, and always contain a good deal of mucilage. 1 Untersuchungen zur Morphologie der Gefasskryptogamen. Heft 2. Die Schizaeaceen, 1881. 2 Studies in the Morphology of Spore-producing Members. IV. The Lepto- sporangiate Ferns, Phil. Trans., 1900. Professor Bower found 128 the typical number for one species of Lygodium , for Anemia and for Mohria. 3 Op. cit. 4 Op. cit. 496 Tansley and Chick. — On the Struchire The stele has a rounded or oval outline, a shape which is frequently distorted by the departure of the leaf-traces. Apparently the leaves normally have a § divergence, but the vertical distance between the exits of successive traces is very variable, so that some transverse sections show two in process of leaving the stele, while others pass across the exit of only one, and others again show the stele entirely undisturbed in this way. In a few cases the insertion of leaves and leaf- traces appears to be quite irregular. The endodermis is composed of cells which have usually less than half the diameter of the cortical ones, with an average of about 30-40 on the circumference. The cells are filled with dense muci- lage. Their outer walls, separating them from the cortex, are thick and brown ; the radial walls are suberized in the usual way. The cells of the pericycle, which has but a single layer, are of about the same size as, and correspond accurately with their sister-cells of the endodermis. Occasionally a pericycle- cell is divided by a tangential wall. Immediately inside the pericycle comes the phloem, con- sisting of a one- or two-layered, almost complete zone of very small sieve-tubes, with practically no phloem-parenchyma. The number of sieve-tubes abutting on the pericycle is two or three times as great as that of the pericyclic cells. The breadth of the sieve-tubes is frequently twice as great in the tangential as it is in the radial direction. The tracheids of the xylem are often in immediate contact with the sieve- tubes of the phloem, i. e. there is no intervening layer of parenchyma such as Mr. Boodle has described in S. digitata , a layer almost universally present in Ferns. Occasionally, however, a few scattered parenchymatous cells are present between the xylem and phloem (a good many in Fig. 5), and in some of the larger steles this layer is constant and con- tinuous. Sometimes the layer of sieve-tubes is itself inter- rupted, so that in places the tracheids abut directly on the pericycle (Figs. 3 and 4). The tracheid-ring is one to two — very rarely more than two (Fig. 5) — cells thick, and, like the 497 of Schizaea malaccana. phloem, has practically no nucleated cells between its elements. The tracheids themselves are narrow ; their thickening is scalariform or slightly reticulate. There is no trace of spiral elements anywhere in the stem. The centre of the stele inside the xylem is one of the great features of interest in this species. In the simplest case there is a homogeneous ‘ pith ’ consisting of living thin-walled parenchymatous cells, of about the same, or rather greater, diameter than the tracheids, and of approximately the same length as the latter, seen in longitudinal section. This tissue has nothing in common (except its position) with the tissue enclosed by the internal endodermis of a solenostele. It is undoubtedly an £ intra-stelar pith,’ as Russow and Prantl held. Sometimes, though rather rarely, there appears in the midst of this central parenchyma a strand, or more seldom two strands, of tracheids, rarely more than two or three in a strand as seen in transverse section, and quite distinct from the xylem-ring (Fig. 4, int. tr.). Followed up in a series of sections, it is found that these strands are sometimes quite isolated, and sometimes connected at one end with the xylem- ring, while the other end has a blind termination in the parenchyma. The arrangement of these strands appears to have no relation whatever to the leaf-traces, and in fact to be quite capricious. The tracheids themselves are quite normally developed, and are identical in structure with those of the xylem-ring. These internal tracheids are only found in the larger steles where there is a comparatively bulky pith. In one specimen from Perak, kindly given us by Mr. R. H. Yapp, a considerably larger number of internal tracheids occurred at a certain level, forming an almost complete band across the pith (Fig. 5). Higher up, the stem dichotomized, but the phenomenon in question had no direct connexion with this, for the internal tracheids all disappeared before the stele began to divide \ The discovery of internal tracheids in the pith of the stele of Schizaea was made by Mr. Boodle in S. dichotoma before we found them in the present species. 498 Tansley and Chick. — On the Structure In other cases, and far more frequently, there appears, also embedded in the central parenchyma, an internal endodermis. Such an endodermis may consist of a ring of as many as thirteen endodermal cells (Fig. 3), having all the characters of those belonging to the external endodermis, and enclosing one or more cells considerably smaller than, but otherwise possess- ing the characters of the cells of the cortex. On following such an internal endodermis upwards (towards the apex of the stem), it is found to be continuous with the ordinary external endodermis at the ‘ axil ’ of the next leaf-trace, while the enclosed cells are continuous with those of the cortex, in exactly the fashion characteristic of a solenostelic Fern. Traced downwards, the internal endodermis ends blindly, usually in the region of the node next below the one to which it belongs. In one case only was a blind termination found also at the upper end. In that case the internal endo- dermis had no connexion whatever with the exterior of the stele. Frequently, however, the internal endodermis, for the whole or for part of its course, encloses no cells, but simply consists of a solid strand, which may be reduced to a single row of endodermal cells. Many of the leaf-traces, however, have no internal stelar endodermis in connexion with them, the endodermis of each being continuous at the ‘axils ’ simply with the external stelar endodermis (second node in Fig. 33). Fig. 33, p. 499, gives a diagrammatic view of a median longi- tudinal section through an actual stem, showing the behaviour of the endodermis at the insertion of three successive leaf- traces. [These insertions are represented as distichous so that they may all three be shown in one plane. In reality they are not so. See p. 496.] When, as is not unfrequently the case, one or more strands of central tracheids coexist with an internal endodermis, the two have no connexion whatever. Phylogenetic significance of the Stelar Anatomy. The bearing of these new facts on the question of the phylo- genetic position of the Sckizaea-stdie are not entirely clear, and must be considered at some length. of Schizaea malaccana. 499 In the first place, we take it, they confirm the idea that the normal central parenchyma of the stele of Schizaea is part of the system of primitive intra-stelar parenchyma, here forming a distinct pith. If we believe, as apparently we must believe, that the ‘protostele’ (Jeffrey) with solid central xylem, as seen in Gleichenia and Lygodium , is the primitive type among Ferns, then we are naturally led to suppose that in Schizaea the central tra- cheids of such a stele are nor- mally replaced by parenchyma, just as is the case in most species of Lepidodendron whose structure is known. Such a change might take place as the result of an in- crease in the circumference of the whole stele unaccompanied by a corresponding increase in the total amount of xylem, so that the centre of the stele be- comes, as it were, vacant as re- gards conducting tissue, and is filled with parenchyma ; or it might happen, and this is more probable in the case of Schizaea , that while the stele remains of the same diameter, or at any rate is not increased in size, the demand of the plant for water- conduction decreases consider- ably, and that, as a result, the central tracheids are no longer developed, but are replaced by parenchyma, among which a few ancestral tracheids still occa- sionally appear. The fact that the species of Schizaea are all comparatively small plants, mostly living in the humus of deeply shaded forests, and with a strikingly small transpiring surface M m Fig. 23. — Schematic longitudinal section of part of an actual stem. Endodermis represented by dotted lines ; xylem cross-hatched, phloem black. 500 Tans ley and Chick . — On the Structure even relatively to the diameter of the stele, makes it ex- ceedingly likely that such a change would take place if we suppose an ancestor of the genus to have had a stele of the type which we find in the allied genus Lyg odium. But these phenomena are distinctly complicated by the occurrence of the internal endodermal pouches and rods in connexion with the leaf-traces, bringing Schizaea into relation with solenostelic forms. Are we to regard these endodermal structures as a progressive modification, constituting an ad- vance on the medullated protostelic type, or as vestiges of a former solenostelic condition ? The main difficulty of the former hypothesis is to see how these endodermal structures, in their present condition, can be of any use to the plant. The same difficulty occurs in con- sidering the downward extension of an internal endodermis from the node of Gleichenia x and Lindsay a 1 2 . Perhaps it may be partly met by the following suggestion. Suppose the diameter of a protostele be increased for any reason while the demand for intra-stelar (i. e. conducting) tissue is not increased ; or suppose, as we are doing for Schizaea , that the diameter remains constant or is only slightly diminished, while the demand for intra-stelar tissue is considerably diminished. The lessened demand for conducting-tissue should affect the intra-stelar parenchyma as much as it will affect the xylem and phloem, since we have reason to believe that the main function of the parenchyma is to conduct carbohydrates. Certainly the proportion of intra- stelar parenchyma in Schizaea , in places where no internal endodermis is present, considerably exceeds the proportion ordinarily found in fern-steles. The central parenchyma here may be directly compared with that found in the roots and stems of some Phanerogams where this central parenchyma or pith is relatively narrow, and does not differ very markedly from the small-celled active tissue immediately connected with 1 Cf. Boodle, The Anatomy of the Gleicheniaceae, Ann. of Bot., Dec. 1901. 2 Cf. Tansley and Lulham, On a new type of Fern-stele, &c., Ann. of Bot., March, 1902. of Schizaea malaccana . 501 the vascular bundles — in other words, where there is no very clear differentiation between the ‘ internal ’ and c external con- junctive 5 of Flot. Such a central parenchyma will tend to become functionless for conducting purposes. In Phanero- gams, when the stele is further dilated, this central tissue takes on the characters of typical ‘ pith , 5 i. e. its cells are short and broad, frequently entirely passive to all appearance, and sometimes even destroyed by the rapid growth of the sur- rounding tissues of the vascular ring. Such a pith obviously forms no functional part of the stele, though it is not separated from the vascular ring by a differentiated endodermis. But the corresponding tissue in Ferns, which is either used for the storage of starch or is sclerotic, is always separated from the vascular ring by a definite endodermis, and it is the origin of this state of things that is perhaps illustrated in Schizaea. The mass of the intra-stelar parenchyma is greatest at the point of departure of a leaf-trace, and here consequently we get the beginnings of its replacement by a physiologically extra-stelar tissue which is definitely non-conducting. This takes the form of what has been described as an c intrusion 5 of cortical tissue into the stele, or, as we should prefer to say, of the develop- ment of a strand of tissue in connexion with the cortex, pene- trating into the stele ; and since the boundary of extra- and intra-stelar tissue is always marked by an endodermal layer, such a strand is always bounded by an endodermis, or may even consist of a mere rod of endodermal cells. In this way the balance of the different intra-stelar tissues is readjusted. So long as the stele does not increase in diameter we have these first beginnings of the development of physiologically extra-stelar tissue within the stele, remaining in the inconstant and irregular condition met with in Schizaea. If the stele were to increase in diameter, however, these pouches of extra-stelar tissue would increase in diameter with it, would meet and open into one another at the nodes, and an ‘ ectophloic siphonostele 5 (Jeffrey) would be formed. The ectophloic siphonostele is, however, the exception in Ferns. The more usual course of evo- lution apparently involves the development of internal phloem M in 2 502 Tans ley and Chick . — On the Structure as the first definite advance on the protostele with solid xylem. This is the condition found in Lindsay a. With further dilation the extra-stelar pouch appears at the node, just as in Schizaea , only here it replaces phloem instead of intra-stelar parenchyma. The meeting and fusion of the pouches, which is in process of happening in Microlepia pinnata , will then result in the forma- tion of the typical ‘amphiphloic siphonostele 1 of Jeffrey or c solenostele ’ of Gwynne- Vaughan 1 . The alternative, and as some will perhaps think, the more natural hypothesis, is that the Schizaea-stzlQ has been derived by reduction from a siphonostelic type, the occasional internal endodermis being a vestige of this former condition. There is no a priori objection to such a view. It must be remembered, however, that no vestiges of internal phloem have been found in a considerable amount of material, and that the ectophloic siphonostele is a rare type in Ferns, no evidence of its existence being forthcoming in any of the allies of Schizaea. Further, the considerable amount of persistent central intra-stelar parenchyma, with its occasional tracheids, is difficult to under- stand on this hypothesis. If Schizaea were really derived by degeneration from an ectophloic siphonostelic type we should rather expect the remains of the internal endodermis to be always close to the xylem-ring. Thus it appears that the hypothesis we have put forward is really the simpler and more natural one, provided the general view of the factors govern- ing the formation of physiologically extra-stelar tissue within the stele be accepted. The Anatomy of the Leaf-trace and Leaf. The leaf-trace (Figs. 3 and 4) consists simply of a section of the stele of the stem which gradually passes off through the cortex at a slight angle with the long axis of the stem. It is therefore strictly collateral and remains so throughout the leaf. It is made up of a short band of phloem, separated by a single sometimes incomplete row of parenchyma from a short band of xylem, the whole surrounded by a peridesm composed of a single layer of rather large cells — those on the outer side 1 Cf. Tansley and Lulham, op. cit. of Schizaea nialaccana . 503 continuous with the pericycle of the stele, those on the inner with the outer cells of the pith — and by an endodermis like that of the stem-stele. The characters of the xylem and phloem are also exactly like those of the stem-stele, spiral tracheids being quite absent. The meristele retains these characters for some millimetres up the leaf, but at a distance of 1 cm. from the leaf-insertion practically all the characters of the leaf-bundle have been acquired. The leaf-bundle (Fig. 6) is circular or rather oval in outline, situated rather nearer the lower than the upper leaf-surface, and surrounded by an endodermis and pericycle exactly like those of the stem. The xylem has the form of a crescentic strand enclosing three or four large parenchymatous cells (which have strikingly large, elongated nuclei) and the band- shaped strand of sieve-tubes between its horns. The body of the xylem crescent is occupied by two large scalariform tracheids, side by side. Between these and the peridesm is a little group of spiral protoxylem-elements (Fig. fpxi), which in the adult leaf are crushed and often nearly obliterated (Fig. 6, fix.) \ The sides of the crescent are occupied by a few narrow scalariform tracheids (tr.), and at each horn, between these lateral tracheids and the sieve-tubes, is a group of fibres (^. t.f.) such as Boodle has described in a similar position in »S. digit ata. As in that plant, they are, pretty clearly, thickened and lignified sieve-tubes, their end walls bearing sieve-plate-like structures (Fig. 7, j. t.f.). The whole bundle in fact, except for the existence of the two large central tracheids, is simply a smaller edition of that found in the other species. In the last few millimetres below the fertile pinnae the spiral elements are not formed, and the parenchyma- cells between the xylem and phloem are smaller. Just below the lowest fertile pinnae the bundle is considerably enlarged, the tracheids increasing to thirty or more in number. As has already been said there is no distinction between petiole and lamina. For the first few millimetres from the 1 There is no trace of the two lateral groups of spiral tracheids described by Prantl in the larger species S. Pennula and S. elegans. 504 Tansley and Chick. — On the Structure base the epidermis and cortex of the leaf resemble those of the stem, but at 1 cm. up, the characteristic mesophyll and leaf-epidermis make their appearance. The mesophyll is distinctly peculiar (Figs. 6 and 8). It consists of very long cells running parallel to the axis of the leaf, with rows of lateral lobes coming off horizontally and joining the similar lobes of other cells so as to leave rounded or angular lacunae between the cells. The lobes sometimes have two arms and are irregular in size and shape, so that they enclose a very irregular network of lacunae (Fig. 6), though they themselves form fairly even longitudinal rows, each row containing eight or ten lobes (Fig. 8). All the mesophyll cells are alike in structure and contents. The epidermal cells are thick-walled, broad, and of con- siderable length. The stomata are arranged in two longi- tudinal rows on the morphologically lower surface of the leaf. In each row every alternate cell becomes the mother-cell of a stoma. The guard-cells project slightly from the general surface of the leaf. Their length is three or four times as great as their transverse diameter. The inter-stomatic cells (; i . st. c. in Figs. 6 and 8) of the stomatiferous rows are shorter and deeper than the ordinary epidermal cells. The Anatomy of the Root. This corresponds with Prantl’s description and illustration of S'. Pennula 1 , but we have thought it well to figure a transverse section of the stele (Fig. 9), as the cells of the phloem are not shown by Prantl. Development of Tissue-systems at the Apex of the Stem. The growing-point of the stem of this plant is rather variable in form. The free apical surface is always flattish, and sometimes forms a perfectly plane surface at right angles to the long axis of the stem. More usually it is slightly convex. There is a well-defined apical cell of an approxi- 1 Prantl, op. cit., p. 38, Taf. IV, fig. 59. of Schizaea malaccana. 505 mately tetrahedral shape, about twice as deep as it is broad (Fig. 10) ; in longitudinal section its side- walls appear nearly parallel to one another towards the free surface, and this character is correlated with the flatness of the apex. Some- times the apical cell and its immediate products occupy a pro- jection or papilla in the centre of the flat meristematic surface. This appears to be the case when growth is very feeble or at a standstill ; the products of segmentation are then much divided, and the resting apical cell has pushed out in front of the general meristematic surface. The apex is protected by numerous mucilage-producing hairs (/i., Fig. 10), which grow out from the cells of the meristematic surface quite close to the apical (the fourth or fifth cell from the apical has often already produced its hair), and bend inwards, usually quite covering the apex. Every one of the peripheral cells of the meristematic surface produces such a hair. Leaves are formed, together with adventitious roots, at a very early period, and one of the former often projects from the shoulder of the growing-point. The sequence of cell-divisions and the origin of the stem-tissues are not altogether easy to follow. This is due partly to the early origin of leaves and roots, the dividing tissues of whose rudiments sometimes force the stem-apex out of the central axis, and disturb the regular arrangement of the initials of the stem-tissues, and partly to the somewhat inconstant and irregular sequence of divisions in these last ; microtome-series are not easy to obtain, owing to the packing of the early-differentiated cortical cells with large starch- grains preventing thorough impregnation with paraffin and consequently causing the sections to break up under the knife. Owing to one or other of these causes we have comparatively few sections in which the whole course of histogenesis is perfectly clear, in spite of the considerable amount of material at our disposal ; but by carefully comparing a number of series, we have arrived at conclusions of whose correctness we have no doubt. We have figured a section in which the course of histogenesis is particularly clear (Fig. 10). Each segment cut off from the apical cell divides first by 506 Tansley and Chick . — On the Str torture a periclinal wall into an outer segment ( o .) and an inner (i.). The latter then divides by another periclinal wall giving rise to an innermost cell (i'.) and a middle cell (mi) of the anticlinal series of three into which the original segment has now divided. Of these o. is a cortical initial, m. an initial of the endodermis, pericycle, phloem and xylem, and i r . an initial of the pith. The divisions of these initials are not entirely constant. The outer cell may divide at once anticlinally, or it may remain undivided for a time and then divide periclinally (commonly into two and almost immediately into four). The middle cell divides by a periclinal wall, which in most cases separates an initial (me.) of the endodermis and pericycle from an initial (mi) of the xylem and phloem. The innermost cell undergoes various divisions, largely horizontal, and the inner- most daughter-cells differentiate very shortly into pith-cells, which are formed so early that they are often only separated from the apical by two or three meristematic cells 1 . To return to the fate of the segments of the middle cell (m .) : on a level with the young pith, at a distance of -14 mm., and separated by about six cells from the apical in the apex figured in Fig. 10, the inner (mi) of its two segments divides by a periclinal wall into two narrow cells, elongated in the direction of the axis of the stem, the inner of which (x.) is a xylem initial, and the outer (ph) a phloem-initial. Both of these elongate, divide by radial and tangential walls, and very soon give rise to tracheids and sieve-tubes. Shortly after the division of mi. into ;tr. and//£., the outer segment (me.) divides tangentially into e. and /., initials of the endodermis and pericycle respectively. Outside these the cortex is now about eight cells thick, but is often disturbed by a leaf-rudiment. Detailed information as to the course of histogenesis at the 1 The appearance of the resting nuclei of the pith-cells is quite different from that of the meristematic cells which give rise to them. The nuclei are smaller and look more homogeneous in our material (fixed in ordinary methylated spirit). They take up haematoxylin much less readily than do those of the meristematic cells, in which chromatin granules are quite obvious. Later on, however, the pith-cells divide again to a certain extent and their nuclei reacquire the meriste- matic appearance. of Schizaea malaccana. 507 stem-apex in Ferns is very scanty, but it appears from the^general statements of Van Tieghem that the first-formed tangential walls generally mark the external limit of the stele or ring of steles, the sheath-layers (pericycle and endodermis) usually arising in common with the cortex outside these early tangential walls. On this ground Russow 1 , believing that histogenesis should be used as a basis for the morphological classification of tissues, proposed to exclude these sheath-layers from the vascular system. Strasburger 2 , as is well known, proposed the name ‘ phloeoterma ’ for the innermost layer of the cortex, using this last term for the belt of tissue external to, and clearly separate from, the young stelar system during histogenesis. In this sense the pericycle and endodermis of monostelic fern- stems nearly always arise from the phloeoterma, and it might be supposed that this layer had a widespread morphological value. But the present case, even should it prove an isolated one 3 , in which the sheath-layers arise, with the vascular ring, from a single initial layer, would appear to destroy this sup- posed morphological value, for we can hardly imagine that the sheath-layers are not homologous (that is phylogenetically identical) throughout the monostelic Ferns. This is a particu- larly striking instance of the untrustworthiness of histogenetic differences as guides to the morphological correspondence of different regions, a conclusion which can be reached on various grounds 4 . It is now, we believe, generally accepted by those who con- cern themselves with the phylogeny of tissues, that single criteria cannot be employed, the only sound method of procedure being a careful comparative consideration of the structures as a whole from every point of view, the adult struc- 1 Vergleichende Untersuchungen, 1872, p. 195. 2 Ban und Verrichtungen der Leitungsbahnen. Hist. Beitr., IV. p. 310. 3 From appearances observed by Mr. Boodle in transverse sections of the stem of Schizaea , it is probable that the type of histogenesis described may be found in other species of the genus. 4 We cannot enter here into the intricacies of the actual relation of histogenesis to the morphology of the adult tissues, but it is proposed to publish shortly a detailed historical and critical account of the whole subject. 50 8 Tansley and Chick . — On the Structure ture, as representing the current state of evolution of the plant body, naturally forming the starting-point of the investigation. Differentiation of Tissues behind the Apex. The further development and differentiation of tissues below the point at which the initials x. and ph. are derived from mi. can best be followed in a series of transverse sections (Figs. 11-13). From these it is seen that the radial and tangential divisions in the layer of xylem- and phloem-initials is by no means constant and regular. The new longitudinal walls are formed in various orders, and division is much further advanced at some places on the circumference of the stele than it is at others. The three zones of stem-tissue derived respectively from o., m., and A, are extremely obvious in Fig. 11. The cortical and pith-cells have thicker and darker walls, the nuclei of the former and some of the latter (those to the left) having already lost their meristematic appearance, while the inter- mediate zone comprising the initials of the vascular ring and sheath-layers is still markedly meristematic. A stage in which there are twice as many xylem- and twice as many phloem- initials as there are pericyclic cells is common, and there are often no further radial divisions in the initials of the vascular ring, but tangential divisions continue irregularly till the ring is four or five cells thick. In spite of this frequent irregularity in division, the common origin of a given endodermal and pericyclic cell with the adjacent xylem- and phloem-initials is often very obvious (e. g. at A in Fig. 12). The endodermis differentiates before the other tissues derived from m., early acquiring the mucilaginous contents which give it such charac- teristic staining reactions. Meanwhile the first sieve-tubes are developed from the outermost phloem-initials at scattered spots on the circumference of the stele (Fig. 12). This dif- ferentiation continues till there is a fairly complete ring of phloem, and then isolated tracheids begin to develop abutting on the pith (Fig. 13). Hence the xylem is technically endarch , though whether this has any morphological significance is perhaps doubtful. It may, however, be noted that the stem- 5 o9 of Schizaeci malaccana . protoxylem corresponds in position with the spiral elements of the leaf-bundle. At the point where a leaf-trace is leaving the stele the tracheids are first formed in the stele above the point of departure of the trace at a higher level than in the trace itself. The tracheids likewise increase in number till they form a fairly complete ring, normally one or two cells thick. The endodermal and pericyclic cells occasionally divide by additional walls, either radial or tangential. The increase in the number of cells on the circumference of the stele is, how- ever, comparatively small from the period of the separation of endodermis and pericycle initials right up to the period when differentiation of all the tissues is complete. EXPLANATION OF PLATES XXV AND XXVI. Illustrating the paper by Mr. Tansley and Miss Chide on Schizaea malaccana. Fig. i. Plant of Schizaea malaccana , half natural size. Fig. 2. Pinnae of a fertile frond seen from below, x 4. Fig. 3. Transverse section of stele of stem of rather small plant (stem *8 mm., stele *2 mm. in diameter) showing departure of a leaf-trace, two endodermal cells, end. r., continuous above with inner part of endodermis of leaf-trace ; and endo- dermal pouch, end. p ., enclosing four cells of same histological character as cortex and continuous with cortex at departure of next leaf-trace above, x 232. Fig. 4. Transverse section of stele of larger stem (stem 1 mm., stele -3 mm. in diameter) showing departure of leaf-trace ; one-sided endodermal pouch, end. /., belonging to it, and enclosing two cells of same histological character as cortex ; endodermal rod, end. r. } consisting of seven cells, belonging to next leaf-trace above ; and internal tracheids, ini. lr., part of a strand continuous with edge of leaf- gap above and ending blindly below, x 270. Fig. 5. Transverse section of stele of large stem (stem 1-5 mm., stele *54 mm. in diameter) showing unusually rapid departure of leaf-trace and closure of gap in xylem-ring. Int. tr., internal tracheids forming almost complete band across the pith, x 100. Fig. 6. Part of transverse section of leaf passing through the two stomatic rows on the lower surface ; on the left a large inter-stomatal cell (i. si. c.) ; on the right a stoma (si.). In the meristele the two lateral groups of fibres (s. t.f.) lie between the sieve-tubes (s. t.) and the lateral tracheids (tr.). Px., obliterated pro- toxylem. x 150. Fig. 7. Longitudinal section passing through side of meristele of leaf. Letters as in Fig. 6. x 200. 510 Tansley and Chick. — On Schizaea malaccana. Fig. 8. Longitudinal section passing through side of leaf showing a stomatal row with the alternation of stomata and inter-stomatal cells, and the armed longitudinally elongated mesophyll cells, x 60. Fig. 9. Transverse section of stele of root with inner layer of cortical cells. Px. proto xylem, phloem, per. pericycle, end. endodermis. x 200. Fig. 10. Median longitudinal section of apex of small stem showing apical cell and common origin of endodermis, pericycle, xylem and phloem from middle segment ( m .) of the anticlinal series of three formed by division of primary segments of apical : 0. outer, m. middle, i'. i r . anticlinally divided inner segment, formed by periclinal division of primary segment of apical cell; me. external segment of m. ( = common mother-cell of endodermis and pericycle), mi. internal segment of m. ( = common mother-cell of xylem and phloem), e. endodermis,/. pericycle, ph. phloem, x. xylem, h. mucilage-forming hair, x 200. Fig. 11. Transverse section of stele of large stem in meristematic region, close behind the apex, showing clear differentiation of the three layers, derived from the three series of cells shown in Fig. 10. The central cells, forming the young pith, p. , have mostly completed their divisions. The nuclei of those to the left (unshaded) have already entered the resting condition in which they take up haematoxylin much less readily. The middle zone, which is the initial zone of the vascular ring and its sheath, is thin- walled, and its inner division, v. r., still often only two cells thick, corresponds to the mother-layers of xylem and phloem. At l. and r. the middle zone is thicker owing to the formation of a leaf-trace and of a root respectively. The outer division of the middle zone is the sheath-layer, or coleogen, col., the mother-layer of endodermis and pericycle. This is still undivided except about the line l. Its cells are thin-walled and have darkly staining nuclei. Their common origin with the mother-layer of the vascular ring is extremely obvious. The outer zone, of which only the inner layers are shown, of larger thick-walled cells with resting (unshaded) nuclei, forms the young cortex, cor. Its divisions are practically complete, x 2 50. Fig. 12. Transverse section of young stele of same stem further back than in Fig. 11, showing coleogen divided into endodermis, end., and pericycle, per., and origin of sieve-tubes. The cells of the young phloem, ph., whose walls are darkly shaded, already show the peculiar light blue colour with fuchsin- iodine-green characteristic of the walls of sieve-tubes in this plant. Some of them still possess nuclei. At A the differentiation of the stele is not so far advanced, and the accurate radial seriation of the mother-cells of endodermis, pericyle, xylem and phloem is well seen. This seriation can also be traced in other parts of the section where the mother-cells of xylem and phloem have already divided. e.r., e.r., two endodermal cells belonging to two endodermal rods (proving the early differentiation of the internal endodermal structures) one of which dies out almost at once, while the other is continuous with an internal endodermis also dying out below, x 240. Fig. 13. Transverse section of stele of same stem further back than in Fig. 12, showing completed differentiation of pericycle and endodermis and of phloem-ring, broken by departure of a leaf-trace ; also progressing differentiation of xylem-ring, x., exhibiting its endarchy. end. p., endodermal pouch, enclosing here one file of cells. 1 . t., leaf-trace with xylem not yet differentiated, x 175. c 'i/innotls of Botany TANS LEY & CHICK. — STRUCTUF end. r. int.br..- enoL. per end Fig. 3 x 232. Fig. 4 x 270. VolIVIT, PUXV. t±-int. tr. : , ■ A T 1 V: A \/L j 1: SCHIZAEA MALACCANA , Baker Annals of Botany VolIVIf PlIXV. E. C. .. G.T. TANSLEY & CHICK. — STRUCT^ P F SCHIZAEA MALACCANA. Baker University Press. Oxford. M= Annals of Botany Vol.IV//, PI XXV/. Fig. 12. x 240. Fig. 13. x 175. ph. w. ? er - University Press Oxford. TANSLEY & CHICK. SCHIZAEA MALACCAN A , Baker. Comparative Anatomy of the Hymeno- phyllaceae, Schizaeaceae and Gleicheniaceae. IV, Further observations on Schizaea 1 . BY L. A. BOODLE, F.L.S. With three Figures in the Text. I N a previous paper on the anatomy of the Schizaeaceae (Boodle, 1901 , p. 373) the vegetative structure of Schizaea digitata , Sw., was treated at some length, and a few observa- tions were added regarding S', dichotoma , Sw., and S. fistulosa, Labill. The two latter species could not be dealt with fully, as small pieces of the dried rhizome formed the whole of the available material. Further material of Schizaea has since been examined, namely, additional specimens of S', digitata , several plants of S', dichotoma , and of S', bifida , two specimens of a small form of S', dichotoma , and some seedling-plants of S', pusilla , Pursh. The structure observed in these species will now be described. Schizaea dichotoma. The general structure of the rhizome of S', dichotoma has already been referred to (Boodle, * 01 , p. 378, PL XIX, Fig. 11, and PI. XX, Fig. 15), but certain important features, which occur locally in parts of the stem of this species, call 1 From the Jodrell Laboratory, Royal Botanic Gardens, Kew. [Annals of Botany, Vol. XVII, No. LXVII. June. 1903.] 5 1 2 Boodle . — Comparative Anatomy of the for special description. These are: dichotomous branching, nodal endodermal pockets, internal endodermis, and internal tracheides. i. Branching. Among the specimens of .S'. dichotoma there were two or three with branched rhizomes. The branching has every appearance of being dichotomous, both on external examination and also in the behaviour of the stele. When preparing for dichotomy the stele becomes elong- ated in the horizontal plane and then divides into two in a simple manner 1 . Three stages of its division are shown in Fig. 24. In this series, after the elongation of the stele, a leaf-trace is given off on the upper side leaving a gap in the xylem and phloem, which becomes very wide (Fig. 24, A); the lower part of the band of xylem and phloem splits in the me- dian plane ; the endo- dermis becomes con- stricted and fuses in the same plane (Fig. 24, B ), producing an hour-glass- shaped double stele, which then separates into two by fission of the endodermal bridge at the neck. The dichotomy of the stele is thus complete (Fig. 24, C). No branching other than apparent dichotomy was observed. The mode of division of the stele (assuming that the latter 1 Internal endodermis and internal tracheides may be present in the region of dichotomy, but do not affect the mode of division of the stele. Fig. 24. — Dichotomy of the stele of S. dicho- toma. A, B, C, three stages in acropetal order, x 9. Endodermis represented by bounding line ; xylem cross-hatched ; phloem shown as a broken line. In C, leaf-trace and root at l.t. and r. Hymenophyllaceae , Schizaeaceae and Gleickeniaceae. 513 is bounded by the endodermis) resembles the dichotomy of the stele of Lyg odium (Boodle, ’ 01 , p. 365), and the behaviour of the phloem in the region of branching gives no evidence for reduction from solenostely. Attention is drawn to this, because in Osmunda cinnamomea the special behaviour of the phloem in the region of forking (viz. the presence, of internal phloem there and its continuity at times with the outer phloem) has been used by Faull (’ 01 , p. 41 1 et seq.) and by Jeffrey (’02, p. 126) as one of their grounds for regarding the present structure of O. regalis , & c., as derived from a solenostelic (amphiphloic siphonostelic) type. Without giving any very decided opinion as to the origin of the stelar structure of Osmunda , the writer wishes to emphasize : firstly, the importance, in any case where phylo- genetic consideration of structure is concerned, of examining a large number of specimens of a given species — as was done by Faull in O. cinnamomea , &c. — so as to obtain any indi- vidual structural variation that occurs within the species ; and secondly, the necessity of a very careful scrutiny of the results in the light of all available evidence suggestive of reduction on the one hand or advance on the other. Compli- cation of structure restricted to a region of branching, just like complication at a node, should be accepted with great caution as a primitive structure, unless it be supported as such by weighty independent evidence. While acknowledging the excellence of the observations detailed in Faull’s paper, it may be pointed out as a serious omission that the seedling-stem of Osmunda cinnamomea is not described in greater detail. One gathers from the state- ments on pp. 396 and 410 of Fault’s paper, and on p. 125 of Jeffrey’s paper (Jeffrey, ’ 02 ), that internal phloem is not present in the transitional region of the stem, but only occurs near the region of branching of the stem 1 . This being so, a grave difficulty arises, for we have two alternative views. 1 In Osmunda regalis Leclerc du Sablon (’90) found in the transitional region a pith with no internal phloem, and Seward (’03, p. 241) found the same in Todea hymenophylloides. 5 1 4 Boodle . — Comparative A natomy of the (1) If we accept the evidence derived from the seedling as thoroughly reliable, the absence of internal phloem in it proves that Osmunda has not been derived from an amphi- phloic siphonostelic form, and that the local occurrence of internal phloem in the mature stem has been entirely misin- terpreted by Faull and Jeffrey. (2) If, on the other hand, one accepts their interpretation of the internal phloem, occasionally present in the mature stem, as a primitive structure, then the absence of a stage in the seedling showing similar structure proves that the ontogeny is not reliable as an index of structural phylogeny. This would strike at the root of Jeffrey’s whole generalization (which is chiefly founded on ontogeny) as to amphiphloic siphonostely being the type of structure which succeeded protostely in Ferns, and gave place in certain cases to medul- lated monostely by reduction 1 . For if the seedling-stem is at all dependable in repeating the structural history of the mature stem, one might of necessity count on Osmunda cinnamomea to show clear ontogenetic evidence of the previous existence of internal phloem, as, on our present assumption, it is a plant so little removed from the solenostelic condition that certain individuals of the species actually produce, by reversion in their mature stems, well differentiated local solenostelic structure. Thus it appears that either the basis of Jeffrey’s theory, referred to above, is unsound, or the structure of Osmunda does not bear out Jeffrey’s interpreta- tion of it, and this genus forms an exception to his genera- lization. The disagreement between Jeffrey’s deductions from the anatomy of the mature plant and the evidence derived from the seedling, has already been pointed out by Scott (’02, p. 209) in a review. The case of Osmunda has been referred to thus fully, because evidence of a similar nature has to be dealt with below in the case of Schizaea. 1 There is certainly no sufficient evidence for regarding an inner endodermis as proving, in cases where it occurs, the previous existence of internal phloem. Hymenophyllaceae , Schizaeaceae and Gleicheniaceae . 5 1 5 2. Endodermal pockets. These are formed in connexion with some of the leaf-traces. One is seen in the transverse sections of the node represented by diagrams A-D in Fig. 25, which are arranged in acropetal order. In A two small endodermal pockets are shown cut transversely (^). They Fig. 25. — Schizaea dichotoma. A , B , C, and D, diagrams showing endodermal pocket ( dichotoma . These facts do not suggest a solenostelic ancestry for Sckizaea, nor derivation from the Lindsay a- type. The first two petiolar bundles are collateral ; hence there is no ontogenetic evidence for the petiolar bundles of Sckizaea being reduced from the concentric type, and this fact favours the conclusion that the stem-structure has not been derived from a solenostelic type. If one brings the supposed seedlings of dichotoma into consideration, the early appearance in them of small endodermal pockets and of rudiments which may represent an inner endo- dermis, while internal phloem is absent, would favour the view of reduction from ectophloic phyllosiphony. Ontogeny and Structure of Mature Plant. The structure of the young plant of Sckizaea has been insufficiently examined owing to lack of material, but such data as were obtained, are in agreement with the view derived from a consideration of the typical mature structure together with its variations in dichotoma. This is stated before giving an opinion as to what relative importance should be attached to different kinds of evidence. A few words may now be said on this subject. Firstly, a study of the development of the tissues from the apical region, as Schoute (’02, p. 90 et seq.) has shown, does not give a morphological criterion. Secondly, the structure of the seedling-stem may give a clue to the phylogenetic origin of the mature structure, but probably what is found in the seedling requires great care in interpretation. Assuming that the transitional region of the stem repeats to some extent the phylogenetic history of the mature structure, it is extremely likely that there may be disturbing factors, which would at times make the evidence quite misleading. Thus certain kinds of reduction in the structure of the mature stem might be attained by one of the stages of the transitional region being continued unchanged in the mature stem, so that the plant would be a kind of permanently embryonic form 528 Boodle . — Comparative Anatomy of the If this were to take place the ontogeny would give no clue to reduction. On the other hand a correlation in development, that is to say a tendency to uniformity of structure at all nodes 1 or in all parts of the stem, may cause the appearance of certain tissues precociously (i. e. at too low a level in the seedling-stem). Thus it is possible that in plants, where the possession of internal phloem is a well-established character in the mature stem, the internal phloem may spread downwards below its proper ontogenetic level. If this were to take place, all deductions from the seedling as to phylogenetic priority of internal phloem as compared with a pith would be quite unreliable 2 . To turn to the Dicotyledons for an illustration, the presence of internal phloem in the pith of the primary root of Asclepias obtusifolia (see Scott and Brebner, ’ 90 , p. 272) is almost certainly due to a downward extension (speaking metaphorically) of the inner phloem of the hypocotyl, and it is not an improbable assump- tion that the internal phloem in the lower part of the hypocotyl itself has originated in a similar way ; otherwise, on onto- genetic grounds, one would have to assume that the ancestry of the plant in question did not include forms devoid of inner phloem. Having pointed out one or two reasons for doubting the value of evidence derived from the stem-structure of the young plant, it will be as well to state what class of data appear to the writer to be important in elucidating a problem like that presented by Schizaea . The following is the method suggested : — 1. Any variations in the different parts of the mature stem or in the stems of different individuals should be noted. 2. Special attention should be paid to the structure of the node (because complications of advance or reversion, or more correctly retension, are to be sought here). 1 Some features in the seedlings of some plants seem to point to the existence of such correlation. 2 The writer does not wish to imply that in every case pith preceded internal phloem. Uniformity in this respect in different phyla is perhaps improbable on general grounds. Hymenophyllaceae , Schizaeaceae and Gleicheniaceae. 529 3. The structure of nearly allied species should be carefully compared with that of the species dealt with. 4. The structure of the young plant should be examined, chiefly to see whether it gives evidence of reduction not indicated by the mature plant, in the form of tissues not represented in a corresponding position in the mature stem. 5. In interpreting all such data obtained, both internal evidence and also independent clues should be sought as tests of advance or reduction. General Theory. In the previous paper on the Schizaeaceae, as the forms included in that Order were found to possess features of special interest in relation to the stele, a discussion of some of the points at issue was given (Boodle, ’ 01 , p. 403 et seq.). It will be well to put together some further considerations on this subject and to restate others. Tansley and Chick (’01) deduce, from their researches on some of the Bryophyta and from the probability of simi- larity of physiological requirements in the unknown primitive ancestors of the Pteridophyta, that in the latter the stem possessed a solid central strand of conducting tissue of the protostelic type and having acropetal development, that leaf- traces were developed independently of this protostele, and that their connexion with it was only a secondary pheno- menon. This view appears well founded on theoretical grounds, and receives a certain amount of support from the fact that most cases of protostelic stems are found among the more primitive Ferns, and that as one passes from the lower to the higher forms the leaf-trace appears to exert more and more influence on the structure and development of the stele (cf. G Wynne- V aughan , ’ 01 , p. 87). If one adopts this view, the tissues of the stele and leaf-trace are not strictly homologous h 1 Hence the writer prefers to retain the terms 1 leaf-trace ’ and ‘ petiolar bundle,’ rather than replace them by the word ‘ meristele/ suggested by Brebner (’ 02 , p. 523) for use in an extended sense. 530 Boodle.— Comparative Anatomy of the Starting with a small protostele and a simple type of petiolar bundle, the following appears a probable course of advance in structure among the Ferns. Increased leaf- surface necessitated increase in sectional area of stele and petiolar bundle. But this was achieved in two different ways, viz. simply by greater diameter in the case of the protostele, and by elongation into a band-shaped structure in the case of the petiolar bundle \ For mechanical reasons the peripheral part of the petiole had to be occupied by sclerenchymatous tissue ; so, to avoid too great diameter in the petiole, the band-shaped bundle became arched. To admit of the inser- tion of a number of large arched bundles, the stele increased its diameter beyond the size required by the exigencies of water- conduction, and the central part of the xylem of the stele was transformed into parenchyma or other tissues. Such central tissue might be parenchymatous or sclerenchymatous at its origin and remain so in certain phyla (especially where the leaf-traces were collateral) ; in other cases it might be paren- chymatous at first, and afterwards have its peripheral part converted into phloem ; or inner phloem and pith might arise simultaneously ; or possibly inner phloem might be produced without an ordinary pith (see Tansley and Lulham, ’02). To return to the petiole, its arched bundle was able to increase its sectional area 1 2 by an incurving of its ends, thus producing the horseshoe-type, which is of such frequent occur- rence among Ferns as pointed out by Gwynne- Vaughan (’01, p. 95), and as seen by reference to the table of diagrams given by Parmentier (’99, p. 340). The division of the petiolar bundle into two or more portions, as found in many Poly- podiaceae, &c. (see Bertrand et Cornaille, ’02, pp. 53, 20 7, &c.), may be connected with the downward extension of the leaf- gap in the stem, or may have originated for mechanical reasons, because a large petiolar bundle would be subjected to consider- 1 Convenient for the insertion of numerous distichous branch-bundles. Whether the primitive petiolar bundle was concentric or collateral must be left an open question, but probably both types existed at a fairly early stage. 2 Without increasing the diameter of the petiole. Hymenophyllaceae , Schizaeaceae and Gleicheniaceae . 531 able strains unless the petiole possessed almost complete rigidity, and the latter would be unsuitable for positions exposed to wind. Thus the theory suggested with regard to the origin of a bundle-system like that found in the petiole of Pteris aquilina , is that a band-shaped primitive bundle became arched and afterwards convoluted and divided 1 . We therefore arrive at a different view as to the origin of the vascular bundles in the petiole of Pteris aquilina from that which the writer would suggest for the vascular system of the stem of the same species 2 (see Jeffrey, ’00, pp. 10-11). Jeffrey in his recent paper (’02, p. 143) states that it is not easy to see why on the views put forward (Boodle, ’ 01 ) ‘ the same view [that applied to the bundles in the adult stem of Pteris aquilina\ should not be taken of the equally complex arrangement of bundles in the petiole.’ What has been said above explains the writer’s view 3 . It should be pointed out that, when one is dealing with a question of morphology and comparing the tissues in two different organs, it is necessary to form a definite theory as to the phylogenetic history of the tissues in both organs before formulating their morphological relations. Further Anatomical Details. The resistance to strong sulphuric acid shown by cell-walls in the cortex, pith, &c., of Schizaea digitata has already been 1 A petiolar bundle of the horseshoe-type may also become closed (presumably by the conversion of the tissue between its ends into vascular tissue), e. g. in some species of Gleichenia (Boodle, ’01 a, PI. XXXIX, Fig. 19 ). In this case the cen- tral tissue of the bundle is regarded as belonging to the historically non-vascular portion of the petiole, which has been invaginated ; so the view corresponds to that held by Jeffrey for the solenosteles in stems. 2 For the stem the theory suggested is that if one could follow the stages in the evolution of its structure, one would find a protostele converted into a solenostele by the replacement of its central tissue by parenchyma and phloem (the two tissues appearing successively or simultaneously), and then by the conversion of part of the central parenchyma into vascular strands. The non-stelar nature of the petiolar bundle is not insisted on here, but simply the theoretical view that the centrally placed parenchyma in the petiole has not been directly derived from vascular tissue. O O 532 Boodle . — Comparative Anatomy of the mentioned (Boodle, ’01, p. 376). .S'. dichotoma was found to behave in a similar way. A transverse section of the rhizome was placed in strong sulphuric acid, with a section of Cncurbita as a control. Some time after the greater part of the cellular tissue in the control had swelled up and dis- appeared, a very different result was seen in the section of Schizaea. The walls of the tracheides were considerably swelled, but sharply outlined walls remained representing practically all the rest of the cells. Previous boiling of the material in water did not alter the effect of the acid. The differentiation of the xylem, as seen in a microtome- series of sections of the stem-apex of S', dichotoma , is irregular. Thus, taking one particular part of the stele as an example, no tracheides were differentiated except one at the extreme outside and one at the extreme inside of the young xylem- ring, while, in other parts of the ring of xylem, tracheides in an intermediate position may be the first to differentiate. The differentiation may also be much further advanced on one side of the stele than on the other, in relation to the nearest leaf-trace. The sieve-tubes of S', dichotoma appear to be of a fairly normal Fern-type. The petiolar bundle of S. dichotoma is of a similar type to that of S. elegans figured by Prantl (’ 81 , Taf. IV, Fig. 40). Fibres are present in the usual position, and protoxylem appears to lie at two points on the upper side. In the leaf the stomata are placed in two neat longitudinal rows, just as in S. pusilla (Britton and Taylor, ’ 01 , p. 14). In the flattened part of the leaf the bundle is similar to that of the petiole, the epidermal cells are very thick-walled, and the stomata are raised. Recent Works treating of the Morphology of Tissues. Reference should now be made to certain views regarding the stele and the morphology of tissues, which have been recently published. Farmer and Hill (’ 02 , pp. 396 and 400) Hymenophyllaceae, Schizaeaceae and Gleicheniaceae. 533 regard the pith as not belonging to the stele. They recognize the difficulty in estimating the morphological nature of a tissue, and state that ; our criteria only become applicable as the adult condition is reached 7 or approached. A thoroughly consistent and strictly morphological treat- ment of tissues is probably an impossibility, and in any case the subject is rather elusive, but in many cases one can draw an opinion from the position of a certain tissue, though suppositions as to the exact mode of its first origin may become necessary. Two cases may be brought forward in which the morphological nature appears fairly certain. The cortical sieve-tubes of Cucurbita must be regarded as derived from cortical cells ; morphologically they are part of the cortex. Secondly, the trabeculae in the sporangium of Isoetes have probably been derived from the sporogenous tissue and, morphologically speaking, represent part of it, — not ingrowths of the surrounding tissue. We will now turn to the stele. It is exceedingly probable that the solid protostele was the universal primitive type, that the more complicated types were moulded from it, and that it never passed through a stage of flattening and rolling round, such as is assumed by the writer for the petiolar bundle of many Ferns. Consequently, whatever tissue is found within the xylem is presumably morphologically stelar. Assuming an exarch protostele, a pith may have originated by incomplete differentiation of the xylem-mass. At any rate if one regards the pith or other central tissue as having arisen in the first place by the transformation of potential tracheides into other tissue elements, these latter should be treated morphologically as part of the stele. The different types of stem-structure in Ferns have probably been derived by a differentiation of the protostele into vascular and non-vascular parts, hence, although the possibility of there being exceptions is kept in view, the writer agrees with Schoute’s conclusion (’ 02 , p. 163) as a provisional generaliza- tion that a single type of stele is found in the stem and root of the vascular plants, viz. monostely ; that is to say, taking O o 2 534 Boodle . — Comparative A natomy of the ‘ stele * and ‘ monostely ’ in a morphological sense, applying as strict morphology as is possible in the case of tissues, and working on the hypothesis set forth in the present paper. As a consequence of this conclusion the description and classification of different types of stelar structure have at present no morphological basis, but only a physiological one, because they refer to specializations of tissue within the morphological unit with which we started. Brebner (’ 02 , p. 548) recognizes the physiological nature of the descriptive terms, which he applies to different types of stelar structure. In the writer’s opinion, also, terms defined as referring to definite types of tissue-arrangement within the stele are useful, and in some cases necessary, but a constant morphological distinction between the different kinds of tissue concerned is not upheld. As to the terms to be employed many already in use are sufficiently suitable. Thus ‘ soleno- stele ’ as defined by Gwynne- Vaughan (’01, p. 73) describes a special arrangement of tissues ; its derivation signifies ‘ tube- stele,’ and whether one regards the stele itself as being tubular, or the vascular part of the stele as being tubular, does not interfere much with the appropriateness of the term. Farmer and Hill (’ 02 , p. 398, &c.) decide to take the vascular strand as their unit for comparative considerations, both pith and the parenchyma forming the leaf-gaps of a solenostelic or dialystelic type being excluded. This is excellent as a physiological treatment of the tissues, but, in accordance with the views adopted in the present paper, the writer holds that it obscures the homologies of the tissues concerned. Leaf- gaps are held to have been originally formed by the replace- ment of vascular tissue by ordinary parenchyma, the first stage possibly consisting in the incomplete differentiation of the tracheides in the region afterwards occupied by the leaf-gap ; and the same view is held with regard to the pith l . To exclude part of a given tissue as soon as it changes its structural nature does not appear to be a morphological treatment. 1 Cf. the case of arrested roots, &c., in Gleichenia (Boodle, ’01 a , p. 732). Hymenophyllaceae , Sckizaeaceae and Gleicheniaceae. 535 Summary. The mature rhizome of Schizaea dichotoma exhibits apparent dichotomy. In the region of dichotomy the stele (as seen in transverse section) undergoes elongation, constriction, and fission. The ring of xylem is open during the process, but no internal phloem is present. In the mature rhizome of vS. dichotoma endodermal pockets are often present at the nodes; an isolated internal endo- dermis is occasionally found and may contain brown sclerotic elements ; isolated internal tracheides sometimes occur. In the stem of the young plant of 5. pusilla no internal phloem is present in the transitional region. In two specimens of a small form of .S', dichotoma, which are probably seedling-plants, and at any rate have protostelic structure in their basal region, no internal phloem was present in the transitional region, but endodermal pockets or rudi- ments jof them were present early in the medullated stage. The deduction, which appears most natural, in the light of the various facts recorded, is that the inner endodermis is a vestigial structure, and that .S', dichotoma owes its typical (or more usual) structure to reduction from a medullated form with inner endodermis (‘ ectophloic siphonostelic ’). The same would probably be true for the other species of Schizaea. There is no evidence for the previous presence of an internal phloem. Conclusion. It is likely that a further structural examination of suf- ficiently numerous specimens of 5. dichotoma and of other specimens of Schizaea may give more safe grounds, than were obtainable from the material examined, for elaborating a theory as to the phylogenetic history of the stele of Schizaea ; and this may be helped by an extended comparison with certain species of Anemia, when their structure also has been examined in a large number of individuals. Both genera will 5 3 6 Boodle. — Comparative A natomy of the probably be productive of further data, useful in considerations on stelar morphology b I wish to express my thanks to Dr. D. H. Scott, F.R.S., to whom I am indebted for many valuable suggestions. I am also indebted to Mr. Maiden, Mr. R. H. Yapp, Mrs. Britton, Mr. E. S. Salmon, and Mr. J. C. Willis, for material of different species kindly placed at my disposal. 1 The writer hopes shortly to be able to publish some further observations on two or three species of Anemia and on Gleichenia pectinata in continuation of the present series. Hymenophyllaceae , Schizaeaceae and Gleickeniaceae . 537 List of Works referred to. Bertrand et Cornaille (’02) : Etude sur quelques caract&ristiques de la structure des Filicinees actuelles. Travaux et Mdm. de l’Univ. de Lille, tom. x. Boodle (’01) : Anatomy of the Schizaeaceae. Annals of Botany, vol. xv, p. 359. (’01 a) : Anatomy of- the Gleicheniaceae. Annals of Botany, vol. xv, P- 703. Brebner (’02) : On the anatomy of Danaea and other Marattiaceae. Annals of Botany, vol. xvi, p. 517. Britton and Taylor (’01) : Life-History of Schizaea pusilla. Bull. Torrey Bot. Club, vol. xxviii, p. 1. De Bary (’77) : Comparative Anatomy, English edition (’84). Farmer and Hill (’02) : On the arrangement and structure of the vascular strands in Angiopteris evecta , &c. Annals of Botany, vol. xvi, p. 371. Faull (’01) : Anatomy of the Osmundaceae. Botanical Gazette, vol. xxxii, p. 381. 4 Gwynne-Vaughan (’01) : Observations on the Anatomy of Solenostelic Ferns. I. Loxsoma. Annals of Botany, vol. xv, p. 71. Jeffrey (’00) : The Morphology of the Central Cylinder in the Angiosperms. Reprint from Trans. Canadian Inst. Jeffrey (’02) : Structure and development of the stem in the Pteridophyta and Gymnosperms. Phil. Trans., ser. B, vol. cxcv, p. 119. Leclerc DU Sablon (’90) : Recherches sur la tige des Fougeres. Annales des Sci. Nat., Bot., 7® ser., tom. xi. Parmentier (’99) : Structure de la feuille des Fougeres. Annales des Sci. Nat., Bot., 8 e ser., tom. ix, p. 289. Prantl (’81) : Unters. z. Morph, d. Gefasskryptogamen. II. Schizaeaceen. Russow (’72) : Vergleich. Unters. d. Leitbiindel-Kryptogamen. Schoute (’02) : Die Stelar-Theorie. Diss. Groningen. Scott (’02) : Prof. Jeffrey’s theory of the stele. The New Phytologist, vol. i, p. 207. Scott and Brebner (’90) : On internal phloem in the root and stem of Dicotyle- dons. Annals of Botany, vol. v, p. 259. Seward (’03) : The Anatomy of Todea. Trans. Linn. Soc., London, 2nd series, Bot., vol. vi, Part V, p. 237. Tansley and Chick (’01) : Notes on the conducting system in Bryophyta. Annals of Botany, vol. xv, p. 1. Tansley and Lulham (’02) : On a new type of Fern-stele and its probable phylogenetic relations. Annals of Botany, vol. xvi, p. 157. Thomas (’02) : The Affinity of Tmesipteris with the Sphenophyllales. Proc. Royal Society, vol. lxix, p. 343. Willis (’02) : Studies in the Morphology and Ecology of the Podostemaceae. Ann. Royal Bot. Gardens, Peradeniya, vol. i, Part IV. Flowers and Insects in Great Britain. Part III. Observations on the most Specialized Flowers of the Clova Mountains. BY J. C. WILLIS, M.A., Director of the Royal Botanic Gardens , Ceylon. AND I. H. BURKILL, M.A., Assistant Reporter on Economic Products to the Government of India. W E now publish our observations on the fertilization, about Clova in the Eastern Grampians, of the flowers specially adapted for the visits of bees and butterflies *. The next part of our paper will complete the series, and will terminate with a general review. Class F § n. Suited for Diurnal Lepidoptera. 91 . Silene acaulis, Linn. [Lit. Brit ., Wilson 2567 ; Arct. 7, 34, 36, 38 ; Aurivillius 78 ; Axell 81 ; Alps 2, 9, 21 b, 34 ; Ricca 2071 ; Pyren. 17.] A marked Lepidoptera-flower at Clova as in the Alps and Pyrenees, Bombi having only been recorded as visiting it in Arctic regions. The flowers are polygamo-trioecious, the hermaphrodite condition being common, and fruit ripening very abundantly. The perfect flowers are proterandrous. The larger flowers have a breadth 1 Pt. I (Lowland flowers), Ann. of Bot. 1895, p. 227 ; II (Clova), do. 1903, p. 313. [Annals of Botany, Vol. XVII. No. LX VII. June, 1903,] 540 Willis and Bur kill. — Flowers and of io mm. and a depth of 8 mm. Two points call for mention : (1) the apparently greater separation of the sexes on the continent, and ( 2 ) the more accessible honey in a form of the species found in Greenland. Visitors. Lepidoptera. Heterocera: Geometridae : (1) Thera variata Schiff., 8. VII. 94, 4. VII. 95, 22. VI. 96, 23-2,700 ft. (2) Larentia salicata Hb., 8. VII. 94, 2,400 ft. Pyralidae : (3) Scopula alpinalis Schiff., sh. 4. VII. 95, 26-2,700 ft. Hymenoptera. Aculeata: Apidae\ (4) Bombus jonellus Kirby, sh. 22. VI. 96, 2,300 ft. Diptera. Empidae\ (5) Empis tessellata F., sh. 22. VI. 96, 2,300 ft. Chironomidae'. (6) Chironomus sp., ? sh. 6-13. VII. 95, 2,000 ft. Coleoptera. (7) Anthophagus alpinus Payk., sh. 4. VII. 96, 22. VI. 96, 25-2,700 ft. (8) Meligethes sp., sh. 15. VI. 99, 1,900 ft. Thysanoptera. (9) Thrips sp., sh. 4. VII. 95, 2,700 ft. 92 . Habenaria conopsea, Reichb. [Lit. Brit. 28 ; Darwin 483; N.C.E. 1 , 4, 16, 44; Arct. 36; Alps 2, 9, 21b.] A Lepidoptera-flower known to be fertilized by moths and butterflies in North Norway, Scotland, England, and the Alps. Some differences in the length of the spur are to be noted ; it is recorded as 10-11 mm. long in North Norway, 15 mm. in South Sweden, 13-14 mm. in the Alps, and is 10-12 mm. long at Clova. We have watched flowers at night without observing insects to visit them. Visitors. Lepidoptera. Rhopalocera : (1) Argynnis aglaia L., sh. 25. VI. 95, 900 ft. once. (2) Lycaena icarus Rott., sh. 1. VII. 95, 900 ft. once. Heterocera: Crambidae'. (3) Crambus sp., sh. 2. VII. 95, 900 ft. Eriocephalidae : (4) Eriocephala calthella L., 8. VI.-2. VII. 95, 8-900 ft. Diptera. Tachinidae\ (5) Siphona geniculata Deg., 22. VI. 95, 800 ft. once. Anthomyiidae : (6) Anthomyia sp., 2. VII. 95, 900 ft., 26. VI. 96, 1,100 ft. Class F § 12. Suited for Nocturnal Lepidoptera. 93. Lonicera Periclymenum, Linn. [Lit. Brit. 23, 39 ; N.C.E. 1, 3c, 8 , 11, 14, 14a, 18, 31, 33; Knuth 1234; Warnstorf 2508 ; Alps 9.] A moth-flower but somewhat visited by bumble-bees. Apis was seen to lick the stigma. Insects in Great Britain. 54i Visitors. Lepidoptera. Heterocera : Noctuidae\ (1) Plusia pul- chrina Haw., sh. 22. VI. 95. Hymenoptera. Aculeata : Apidae : (2) Apis mellifica L., cp. and seeking h. 20-22. VI. 95. (3) Bombus hortorum L., sh. 22. VI. 96, 18. VI. 99. Diptera. Empidae'. (4) Empis punctata Mg., seeking h. 21. VI. 96. Anthomyiidae : (5) Trichophthicus sp., fp. 20-23?. VI. 95. All at 800 ft. Class H § 13. Lychnis Type. 94<> Lychnis diurna, Sibth. [Lit. Brit . 23 , 39 ; White 2548 ; N.C.E. 1, 11, 21 a, 34 ; De Vries 2460 ; Arct. 36 ; Alps 2 , 9 , 16 .] This flower is little visited at Clova, where the tube is 10-1 5 mm. long. In the Alps many butterflies seem to go to it. Visitors. Diptera. Syrphidae : (1) Platychirus manicatus Mg., ? fp. 15. VI. 99, 900 ft. (2) Rhingia campestris Mg., sh! 25. VI. 95, 800 ft. Coleoptera. (3) Meligethes viridescens F., sh. and fp. 25. VI. -4. VII. 95, 15. VI. 99, 8-900 ft. 95. Lychnis flos-cuculi, Linn. [Lit. Brit. 23 ; N.C.E. 1, 3 b, 14 , 16 , 18 , 21 a, 21 b, 25 , 34 ; De Vries 2460 ; Alps 9 .] A bee and Lepidoptera-flower, with (at Clova) a tube 7-9 mm. long. Visitors. Lepidoptera. Rhopalocera : (1) Lycaena icarus Rott., sh. 26. VI. 95, 800 ft. Hymenoptera. Aculeata: Apidae : (2) Bombus lapponicus F., seeking h. 26. VI. 95, 800 ft. (3) B. agrorum F., sh. 21. IX. 95, 900 ft. Diptera. Syrphidae'. (4) Rhingia cam- pestris Mg., sh. 26. VI.-i. VII. 95, 800 ft. (5) Platychirus manicatus Mg., seeking h. and fp. 23. VI.-4. VII. 95, 800 ft. Empidae\ (6) Empis tessellata F., sh. 1. VII. 95, 800 ft. Anthomyiidae'. (7) 1 sp., 23. VI. 95, 800 ft. g6. Lychnis alpina, Linn. [Lit. Brit. 26 ; Arct. 36 , 38 ; Axell 81 ; Alps 9 , 34 ; Kirchner 1185 .] The following account is drawn up from Clova specimens. The flower is strongly proterandrous. After the dehiscence of the anthers, the stamens bend outwards ; then the styles elongate and separate, bending so as eventually to be at right angles to the ovary across the mouth of the flower. Ultimate autogamy is possible by 542 Willis and Bur kill. — Flowers and means of anthers still adhering to their filaments, and seems to take place, fruiting being regular. The flowers are 12- 14 mm. in diameter; the petals have a claw 3 mm. long and a limb 4 mm. notched to halfway. As the internode between sepals and petals is about 1 mm. long, the honey at the base of the flower is about 4 mm. removed from the mouth, a distance a little less than the width of the mouth. Thus the tube is rather funnel-shaped than tubular. The flowers are very variable in the number of parts, six petals being frequently, seven occasionally, present. It is possible that the flower should be regarded as belonging to Class B. Visitors. Hymenoptera. Aculeata: Apidae : (1) Psithyrus quadricolor Lep., sh. 2. VII. 96, once. Diptera. Chironomidae : (2) 1 sp., 2. VII. 96. Anthomyiidae : (3) Trichophthicus sp., sh. 27. VI.-2. VII. 96. Thysanoptera. (4) Thrips sp., 2. VII. 96. All at 2,850 ft. 97. Primula vulgaris, Huds. [Lit. Brit. 23 , 29 ; Christy in Trans. Essex Field Club, iii. p. 195 ; Darwin 470 and 485 ; Briggs 290 ; Scott 2253 ; N.C.E. 1, 33 .] One of us gave some account of the fertilization of the Primrose (see lit. 29) a few years ago, showing how the conditions of its fertilization are hardly known. Since then we have noticed that it is very abundantly visited at Kew by a bee, Anthophora acervorum , and is visited also by it in Essex (see Miller Christy, loc. cit). This insect does not occur at Clova. We have seen few visitors in our district. The tube is 12*5-16 mm. long there ; it is longer in England and Germany. We found certain long-styled flowers with the style dwarfed, probably in deformity, and in them the Anthomyiids were able to push their way down the throat to the stamens. Visitors. Hymenoptera. Aculeata: Apidae : (1) Bombus hor- torum L., sh. 20. V. 97, 800 ft. once. Diptera. Anthomyiidae'. (2) Anthomyia sulciventris Ztt., fp. and seeking h. 20-22. V. 97, 6-1,200 ft. freq. (3) Hylemyia sp., fp. 20. V. 97, 900 ft. Coleoptera. (4) Meligethes sp., fp. 22. V. 97, 10. VI. 99, 700 ft. Araneida. (5) Xysticus sp., lying in wait on the corolla, 22. V. 97, 600 ft. Insects in Great Britain , 543 Class H § 14. Crocus Type. 98 . Crocus aureus, Linn. [Lit. Brit. 29.] In cultivation. Visitors. Hymenoptera. Aculeata : Apidae : (1) Apis mellifica L., sh. and cp. 2-15. IV. 95, very ab. Diptera. Muscidae : (2) Pollenia rudis F., fp. 2. IV. 95, freq. (3) Lucilia cornicina F., fp. 2. IV. 95, freq. All at 800 ft. Class H § 15. Viola Type. 99 . Viola palustris, Linn. [Lit. Brit. 23; N.C.E. 14.) Reproduction is largely by runners. The flowers are insignifi- cant, with a spur only 2 mm. long and with little honey. The stigma projects beyond the stamens. They are neglected by insects, so that we have only seen three individuals on them ; the fourth (B. lapponicus) was observed on the flowers by the father of one of us, Mr. I. H. Burkill, sen. Knuth observed no visitors in the North Friesian Islands. Visitors. Hymenoptera. Aculeata: Apidae: (1) Bombus lapponi- cus F., sh. 19. V. 98, 1,400 ft. once. Diptera. Empidae : (2) Empis lucida Ztt., sh. 12. VI. 99, 17-2,500 ft. Anthomyiidae : (3) 1 sp., 18. V. 98, 800 ft. 100 . Viola canina, Linn., and V. sylvatica, Fries. [Lit. Brit. 23, 29 ; Bennett 219 ; N.C.B. 1, 3 b, 14, 18, 25, 33, 40 ; MacLeod 1471 \ Alps 2 .] Pronounced bee-flowers, but not well visited at Clova. The spur of V. sylvatica sometimes attains the length of 8 mm., that of V. canina (segregate) is about 5 mm. long. Once in the first-named it was found bitten through. The butterflies abroad in spring visit the flowers on the continent as at Clova ; Bombi are recorded as visitors in Dumfriesshire and Yorkshire. The chasmo- gamic flowers seem to set little seed (cf. Linton in Bot. Exchange Club Rep. 1890, p. 384). Cleistogamic flowers follow them. Visitors. Lepidoptera. Rhopalocera : (1) Pieris napi L., sh. 21. V. 96, 23. V. 97, 15. VI. 99, 6-1,000 ft. (2) Argynnis selene Schiff., sh. 15-16. VI. 99, 900 ft. Hymenoptera. Aculeata: Apidae : (3) 544 Willis and BurkilL — Flowers and Bombus agrorum F., sh. 22. V, 97, 600 ft. Diptera. Tachinidae\ (4) Siphona geniculata Deg., 21. V. 9 6, 800 ft. Anthomyiidae'. (5) Anthomyia sulciventris Ztt., fp. 20-27. V. 97, 7-800 ft. Araneida. (6) Xysticus sp., lying in wait inside a flower, 21. V. 97, 800 ft. 101. Viola tricolor, Linn. [Lit. Brit ., Bennett 209 ; Dar- win 482 ; Kitchener 1197 ; N.C.E. 1 , 8 b, 9 , 11, 14 , 18 , 25 , 35 , 40 ; Sccind.) Wittrock 2592 ; Alps 9 , 34 ; Pyren. 17 .] The following statement shows it to be at Clova a neglected bee- flower ; it is not abundant, and owes its position high up the glen perhaps to cultivation. Verhoefif points out the possibility of self-pollination in the Friesian islands and the frequency with which the spur is bitten through for its honey. Visitors < Lepidoptera. Rhopalocera: (1) Pieris napi L., sh. 17. VII. 95, 800 ft. Diptera. Anthomyiidae : (2) Hyetodesia incana W., 19. VI. 95, 800 ft. 102. Viola lutea, Smith. [Lit. Brit. 39 ; Scand. 34 .] A neglected bee-flower. Bombi and butterflies are recorded as visiting it near Stockholm. On the hundreds of thousands of flowers seen by us at Clova, but fifty insects have been recorded, representing sixteen species, mostly flies which sit on the flower licking the hairs at the mouth of the tube or feeding on pollen. Four species of Lepidoptera were seen on the flowers, each once. The flowers are almost always wholly yellow, and all turn towards the south. The spur is 5-6 mm. long. Visitors. Lepidoptera. Rhopalocera: (1) Pieris napi L., 24. V. 96, 800 ft. (2) Lycaena icarus Rott., sh. 18. VII. 96, 800 ft. Hetero- cera: Tineidae\ (3) Glyphipteryx fuscoviridella Haw., sh. 2. VII. 95, 900 ft. Eriocephalidae\ (4) Eriocephala calthella L., 2. VII. 95, 800 ft. Hymenoptera. Aculeata : Apidae\ (5) Andrena analis Panz., 22. VI. 96, 1,000 ft. Diptera. Syrphidae : (6) Sphaerophoria sp., 6. VII. 94. Bibionidae : (7) Dilophus sp., 1 9. V. 97, 800 ft. Muscidae : (8) Pollenia rudis F., licking the hairs at the mouth of the tube, 21. V. 96, 800 ft. Anthomyiidae : (9) Drymia hamata Fin., sh. 4. VII. 95, 800 ft. (10) Hyetodesia incana W., 21. VI. 95, 800 ft. (n) An- thomyia sulciventris Ztt., seeking h. and fp. 19-27. V. 97, 16. V. 98, Insects in Great Britain . 545 7-800 ft. (12 and 13) A. 2 spp., fp. 4. VII. and 21. IX. 95 ; 10. VI. 99, 7-1,500 ft. (14) Coenosia sp., 1. VII. 95, 900 ft. Cordyluridae\ (15) Scatophaga stercoraria L., 4. VII. 95, 800 ft. (16) 1 sp., 2. VII. 95, 800 ft. Class H § 16. Orchis Type. 103. Orchis maculata, Linn. [Lit. Brit ., Darwin 483 ; N.C.E. 1, 3 a, 14, 18, 34, 40; Warnstorf 2506; Alps 2.] A bee-flower apparently much neglected about Clova. The spur contains no free honey and requires a breaking of the tissues to yield any sweet juice. Visitors. Lepidoptera. Rhopalocera : (1) Pieris napi L., seeking h. 19. VI. 96, 1,500 ft. Diptera. Anthomyiidae : (2) Hylemyia variata Fin., seeking h. 21. V. 95, 800 ft. (3) H. nigrescens Rnd., sitting on flower, 16. VI. 99, 800 ft. 104. Orchis mascula, Linn. [Lit. Brit., Darwin 483 ; N.C.E. 1.] Visitors. Diptera. Anthomyiidae : (1) One sp., 22. VI. 95, 1,400 ft. Cordyluridae : (2) Scatophaga stercoraria L., 5. VII. 94, 800 ft. Class H § 17. Tropaeolum Type. 105. Tropaeolum speciosum, Poepp. and Endl. In cultiva- tion. Visitors. Hymenoptera. Aculeata : Apidae : (1) Bombus agrorum F., sh. 19. IX. 95, 800 ft. Class H § 18. Pinguicula Type. 106. Pinguicula vulgaris, Linn. [Lit. N.C.E. 14; Buchenau in Bot. Zeitung, 1865, p. 95 ; Hildebrandt 1041 ; Arct. 36, 38 ; Warming 2498 ; Alps 2, 9.] A self-fertilizing flower, abundant, but as neglected by insects about Clova as elsewhere. Lind- man remarks the great rarity of visitors. Sprengel, Kerner, and Warming describe the way in which the stigma rolls back on to the anthers, and in sections of the flower we have seen the pollen-tubes passing into the stigmatic tissue. Abnormal flowers are very common ; in these it is usual for the number 546 Willis and Burkill. — Flowers and of lobes of the corolla to be increased. Lindman speaks of it being frequently abnormal, and he also notices the occurrence in the Dovrefjeld of flowers which are almost cleistogamic. At Clova it is very frequently abnormal, generally by the addition of extra lobes to the corolla. Visitors. Lepidoptera. Rhopalocera : (i) Pieris napi L., sh. going from flower to flower, 15. VI. 99, 800 ft. Hymenoptera. Aculeata: Apidae : (2) Bombus lapponicus F., settled on a flower but did not stay to sh. 1. VII. 96, 2,000 ft. Diptera. Anthomyiidae : 1 sp., seen settled on flowers on five occasions, 27. VI. 96, 10. VI. 99, 8-2,500 ft. Class H § 19. Pedicularis Type. 107. Pedicularis sylvatica, Linn. [Lit. Brit. 23 ; Ogle 1904; N.C.E. 1,3 c, 4, 12, 14, 18, 21b, 34.] The position of the flowers of this species is constant, the hood always above and vertical. The tube is 14-16 mm. long. Visitors. Lepidoptera. Rhopalocera: (1) Pieris napi L., sh. 19. VI. 96, 15. VI. 99, 8-1,500 ft. Hymenoptera. Aculeata : Apidae : (2) Bombus lapponicus F., seeking h. 11. VII. 96, 800 ft. once. (3) B. jonellus Kirby, ? sh. 22. VII. 95, 1,200 ft. once. Diptera. Antho - myiidae\ (4) Anthomyia sulciventris Ztt., seeking h. or p. 23. V. 97, 900 ft. 108. Pedicularis palustris, Linn. [Lit. Brit. 23; N.C.E. 4, 8, 14, 16, 18, 21 a ; Arct. 36 ; Alps 2.] The position of the flowers is not constant. No one has seen this plant richly visited. Visitors. Diptera. Syrphidae\ (1) Rhingia campestris, Mg., sh. 2. VII. 95, 800 ft. 109. Melampyrum pratense, Linn. [Lit. Brit. 23 ; N.C.E. 1, 3 c, 4, 16, 18, 21 b, 32, 33, 34, 40 ; Alps 9.] A flower distinctly suited to Bombi, but not much visited. Visitors. Hymenoptera. Aculeata : Apidae : (1) Bombus lapponi- cus F., sh. 27. VI. 95, 2,100 ft. Insects in Great Britain . 547 Class H § 20. 1 Labiate ’ Type. iio. Euphrasia officinalis, Linn. [Lit, Brit. 23; N.C.E. 1, 3 c, 4, 14, 18, 21 b, 30, 40 ; Wettstein 2539 ; Arct. 36, 37 c, 38 ; Alps 2, 9, 21 b, 34 ; Wettstein 2539 ; Pyren. 17.] The flower varies considerably in size, but the mechanism does not change. In the glen the tube is usually 2*5 mm. long. Visitors. Hymen optera. Aculeata : Apidae : (1) Apis mellifica L., sh. 15. IX. 95, 800 ft. once. Diptera. Syrphidae : (2) Platychirus manicatus Mg., fp. 14. IX. 95, 800 ft. in. Nepeta Glechoma, Benth. [Lit. Brit. 23, 29, 34 ; Bennett 212 ; Marquand 1513 ; N.C.E. 1, 3 c, 4, 16, 18, 21 a, 21b, 33, 34, 40; De Vries 2460; Alps 34; N.Am. 19 c.] Gynodioecious ; the tube of the flower is 4 mm. long. Visitors. Hymenoptera. Aculeata: Apidae : (1) Apis mellifica L., sh. 20. V. 97, 800 ft. Diptera. Anthomyiidae : (2) Anthomyia sp., fp. 20. V. 97, 800 ft. 1x2. Prunella vulgaris, Linn. [Lit. Brit. 23, 39 ; Ogle, 1904 ; N.C.E. 1, 3 c, 4, 11, 14, 14 a, 16, 18, 21 a, 21 b, 30, 32, 34 ; De Vries 2460 ; MacLeod 1473 ; Arct. 34 ; Alps 2, 16, 21 b, 34 ; Pyren. 17 ; N.Am. 19 c.] The tube of the decidedly proterandrous flower is usually 9-10 mm. long. We found, however, a larger-flowered form an the crags at 2,000- 2,800 feet. Visitors. Hymenoptera. Aculeata : Apidae : (1) Bombus hortorum L., sh. 11. VII. 96, 800 ft. 113. Stachys palustris, Linn. [Lit. Brit. 23; N.C.E . 1, 3 c, 4, 8, 11, 18, 21 b, 32, 33 ; Alps 16 ; Pyren. 17.] Visitors. Hymenoptera. Aculeata: Apidae'. ( 1 ) Bombus agrorum F., sh. 2. VII. 95. Diptera. Syrphidae'. (2) Rhingia campestris Mg., sh. and fp. 2-6. VII. 95. All at 800 ft. 114. Galeopsis Tetrahit, Linn. [Lit. Brit. 23, 39 ; N.C.E. 1, 3 c, 4, 18, 21 b, 33, 40 ; Alps 2, 9, 34 ; Briquet 293 ; Pyren. 17.] The form with rose flowers is very rare. Visitors. Lepidoptera. Rhopalocera: (1) Lycaena icarus Rott., P p 548 Willis and Bur kill. — Flowers and sh. 5. VII. 95, 800 ft. (2) Coenonympha pamphilus L., sh. 5. VII. 95, 800 ft. each once. Hymenoptera. Aculeata: Apidae\ (3) Bombus terrestris L., sh. 16-17. IX. 95, 7-800 ft. (4) B. agrorum F., sh. 5. VII. and 13. IX. 95, 7-800 ft. Diptera. Syrphidae'. (5) Melanostoma mellinum L., fp. 22. IX. 95, 800 ft. (6) Platychirus albimanus F., fp. 16-17. IX. 95, 800 ft. (7) P. manicatus Mg., fp. 5. VII. 95, 800 ft. Muscidae : (8) Calliphora erythrocephala Mg., fp. 5. VII. 95, 800 ft. Anthomyiidae : (9) Anthomyia sp., fp. 17. IX. 95, 800 ft. (10) Tri- chophthicus sp., fp. 16. IX. 95, 800 ft. Coleoptera. (n) Meligethes viridescens F., 16-17. IX. 95, 800 ft. 115. Lamium purpureum, Linn. [Lit. Brit. 23, 29, 34 ; Bennett 212; N.C.E. 1, 3c, 4, 11, 14, 16, 18, 21b, 34, 40; De Vries 2460 ; Alps 34.] The flower is proterandrous; the stigma gradually passes above the stamens to a point beyond them, but not so much as to make self-fertilization impossible. Visitors. Diptera. Syrphidae : (1) Platychirus discimanus Lw., ? fp. 15. V. 98, 800 ft. 116. Lamium maculatum, Linn. [Lit. N.C.E. 1, 3 c, 4, 21 b, 33, 34, 35; Alps 2, 34.] This plant has been established since at least 1840 without spreading to any extent. Some Bombus, not seen by us in the act, bores the corolla, and Apis makes use of the holes. Visitors. Hymenoptera. Aculeata: Apidae : ( 1 ) Apis mellifica L., cp. 20. V. 97, and sh. through holes in corolla and cp. hanging under hood, 7-15. V. 98. (2) Bombus hortorum L., sh. 22. V. 97. (3) B. agrorum F., sh. 23. V. 97, 11. VI. 99. Diptera. Syrphidae'. (4) Platychirus sp., fp. 23. V. 97. Muscidae'. (5) Lucilia cornicina F., 7. V. 98. Anthomyiidae'. (6) Anthomyia sp., fp. 16. V. 98. All at 800 ft. 117. Ajuga reptans, Linn. [Lit. Brit. 23 ; N.C.E. 1, 3 c, 4, 16, 18, 21 a, 21 b; 33, 40 ; Alps 2, 34 ; Pyren. 17.] Visitors. Hymenoptera. Aculeata : Apidae : (1) Bombus agrorum F., sh. 24. VI. 95, 10. VI. 99, 7-800 ft. Diptera. Anthomyiidae'. (2) 1 sp., fp. 10. VI. 99, 700 ft. Insects in Great Britain. 549 Class H § 21. Explosive Leguminous Type. 118. Genista anglica, Linn. [Lit. N.C.E. 1 , 3 b, 14 , 14 a, 34 , 40 .] A species little visited at Clova, where the genera of mid-tongued Hymenoptera observed on it by Muller, Alfken, and Hoppner are poorly represented. Visitors. Hymenoptera. Aculeata : Apidae : (1) Apis mellifica L., cp. 2. V. 97, 7-800 ft. (2) Bombus terrestris L., cp. and seeking h. 25. V. 97, 800 ft. (3) B. lapponicus F., seeking h. 22. V. 97, 700 ft. Diptera. Anthomy iidae : (4) Anthomyia sulciventris Ztt., fp. and seeking h. 20-22. V. 97, 8-900 ft. 119. Ulex europaeus, Linn. [Lit. Brit. 23 , 29 ; Ogle 1905 ; N.C.E. 8, 14 , 18 , 33 .] Apis is a more frequent visitor than the Bombi, but both genera are regular visitors in Scotland and in England. Apis visits the flowers abundantly in Flanders. After explosion a variety of flies find pollen enough to attract them. Many times we have seen the Bombi and Apis thrusting their proboscis into the base of the flower seeking for honey. Visitors. Hymenoptera. Aculeata: Apidae'. (1) Apis mellifica L., cp. and seeking h. 21. V. 96, 20-22. V. 97, 7-16. V. 98, 10. VI. 99, 6-900 ft. (2) Bombus terrestris L., cp. and seeking h. 20-27. V. 97, 10-19. VI. 99, 7-800 ft. (3) B. lapponicus F., seeking h. 20-27. V. 97, 7-800 ft. (4) B. agrorum F., 27. V. 97, 800 ft. Diptera. Syrphidae : (5) Syrphus sp., fp. 20-27. VI. 97, 800 ft. Muscidae : (6) Pollenia vespillo F., fp. 27. V. 97, 800 ft. Anthomyiidae : (7) An- thomyia sulciventris Ztt., fp. 19-27. V. 97, 7-900 ft. (8) A. sp., fp. on exploded flowers, 16. V. 98, 700 ft. Thysanoptera. (9) Thrips sp., 21. V. 97, 800 ft. 120. Cytisus scoparius, Link. [Lit. Brit. 23 , 34 ; Henslow 990 ; Darwin 991 ; N.C.E. 1 , 3 b, 14 , 16 , 18 , 25 , 33 , 34 , 40 ; De Vries 2460 .] The flowers are very well visited, the bees (Apis and Bombi) proceeding from flower to flower regularly. Apis is more abundant than the Bombi : second in abundance is Bombus terrestris ; Anthomyiids and Meligethes viridescens are very common on exploded flowers. It is obvious, as P p 2 550 Willis and Burkill. — Flowers and Muller remarks, that the flower is more sure of advantage from the visits of Bombi than of Apis ; but at Clova, in Flanders, Westphalia, &c., the latter is the more abundant visitor. Visitors . Hymenoptera. Aculeata : Apidae : (i) Apis mellifica L., cp. and seeking h. 19. VI. 95, 21-22. V. 96, 24. V. 97, 10. VI. 99, 7-800 ft. freq. (2) Bombus terrestris L., cp. and seeking h. 21- 22. V. 96, 22-27. V. 97, 16. VI. 99, 7-800 ft. freq. (3) B. lap- ponicus F., sp. and seeking h. 23. VI. 96, 800 ft. once. (4) B. agro- rum F., seeking h. 21. VI. 95, 800 ft. once. (5) B. pratorum L., 10. VI. 99, 800 ft. once. Myrmicidae\ (6) Myrmica rubra L., seeking h. 23. VI. 95, 800 ft. once. Formicidae\ (7) Formica fusca Latr., seeking h. 23. VI. 95, 800 ft. once. Diptera. Syrphidae : (8) Syrphus ? ribesii L., seeking h. 17-23. VI. 95, 800 ft. and ? the same once at 2,300 ft. Muscidae : (9) Calliphora sp., 17. VI. 95, 2,300 ft. Antho- myiidae : (10) Hyetodesia incana W., seeking h. 17. VI. 95, 2,300 ft. (11) Anthomyia sp., fp. 19-23. V. 97, 16. VI. 96, 20-26. V. 97, 10. VI. 99, 7-800 ft. (12) Trichophthicus sp., fp. 19-23. V. 97, 7-800 ft. (13) Azelia aterrima Mg., seeking h. 17. VI. 95, 2,300 ft. Sapromyzidae : (14) Lauxania cylindricornis F., 23. VI. 95, 800 ft. (15) L. elizae Mg., 23. VI. 96, 800 ft. Coleoptera. (16) Meligethes viridescens F., fp. 15. VI. 95, 24. VI. 96, 10. VI. 99, 800 ft. (17) M. aeneus F., 15. VI. 95, 800 ft. (18) Anthobium torquatum Marsh., seeking h. 23. VI. 95, 24. VI. 96, 800 ft. (19) Ceuthorrhynchidius sp., ? sucking the juice of the flower, 24. VI. 96, 800 ft. Hemiptera. (20) Hetero- cordylus tibialis Hahn., 19-23. VI. 95, 8-900 ft. freq. Class H § 22. Leguminous Type. 121. Cytisus Laburnum, Linn. [Lit. N.C.E. 1 , 9 , 33 , 40 .] In cultivation. As honey is obtained by boring the tissues the range of visitors is narrowed considerably, for none but Apis and Bombi find how to obtain it. Visitors. Hymenoptera. Aculeata: Apidae \ (1) Apis mellifica L., ab. (2) Bombus terrestris L. ^(3) B. lapidarius L. All sucking the juices of the flower, 21. V. 96, 800 ft. 122. Trifolium pratense, Linn. [Lit. Brit. 23 ; Darwin 482 ; N.C.E. 1, 3 b, 11 , 14 , 14 a, 15 , 16 , 18 , 21 b, 25 , 30 , 31 , Insects in Great Britain . 55i 32, 33, 34, 40 ; De Vries 2460 ; Arct. 36 ; Alps 2, 34 ; Pyren. 17; N.Am . 19 a.] Contrasting it with T. repens the effect of the greater length of the tube in inviting long-tongued Hymenoptera and Lepidoptera is evident. According to Verhoeff insects on the Friesian coast require tongues il- ls mm. long, and to Muller 9 mm. long; at Clova 8 mm. would suffice. Apis and some of the shorter-tongued Bombi and other Hymenoptera are recorded as obtaining honey by perforation of the calyx. A honey-bird visits it in the United States. Our observations need extending. Visitors. Hymenoptera. Aculeata : Apidae : (1) Bombus terrestris L., sh. 22. IX. 95, 800 ft. (2) B. venustus Smith, sh. n. VII. 96, 700 ft. Diptera. Bibionidae\ (3) Bibio pomonae F., seeking h. 11. VII. 96, 700 ft. Muscidae : (4) Lucilia cornicina F., fp. 5. VII. 95, 700 ft. Anthomyiidae'. (5) Anthomyia sulciventris Ztt., fp. 2. VII. 95, 900 ft. (6) A. sp., fp. 22. IX. 95, 800 ft. Coleoptera. (7) Meligethes viri- descens F., cp. and fp. 23. VI. 95, 800 ft. Each once. 123. Trifolium hybridum, Linn. [Lit. N.C.E. 3 b, 9, 33, 34 ; Kirchner 1183.] Cultivated, and well visited by Apis. Visitors. Hymenoptera. Aculeata: Apidae : (1) Apis mellifica L., sh. 5. VII. and 22. IX. 95, 25. VI. 96, 7-800 ft. Diptera. Mus- cidae'. (2) Lucilia cornicina F., fp. 5. VII. 95, 700 ft. 124. Trifolium repens, Linn. [Lit. Brit. 23 ; Darwin 468 and 482 ; Marquand 1513 ; N.C.E. 1, 3b, 4, 11, 14, 14a, 15, 16, 18, 25, 30, 31, 32, 33, 34, 40 ; De Vries 2460 ; Arct . 34, 36 ; Alps 2, 34 ; Pyren. 17.] A Bombus-flower which by the accessibility of the honey attracts Apis in great numbers. In Arctic Norway Bombi are its only recorded visitors ; they are the most abundant visitors in the Alps and in the Pyrenees. In North Central Europe and in Britain where bees are kept Apis is perhaps more frequent than the Bombi. Darwin demonstrated in England the need of insect aid in pollination. Visitors. Lepidoptera. Rhopalocera: (1) Coenonympha pamphilus L., sh. 22. VI. 95, 800 ft. • (2) Lycaena icarus Rott., sh. 26. VL-i. VII. 95, 10. VII. 96, 800 ft. Heterocera: Geometridae : (3) Cam- 552 Willis and Bur kill. — Flowers and ptogramma ?, sh. n. VII. 96, 700 ft. Hymenoptera. Aculeata: Apidae : (4) Apis mellifica L., sh. 24. VI.-22. VII. 95, 5-1 1. VII. 96, 7-800 ft. (5) Bombus pratorum L., sh. 4. VII. 95, 800 ft. (6) B. lapponi. cus F., sh. 20. VI. 95, 18. VI.-10. VII. 96, 8-2,300 ft. (7) B. agrorum F., sh. 22. VI.-6. VII. 95, 800 ft. (8) B. venustus Smith, sh. 26. VI. 95, 800 ft. Diptera. Empidae : (9) Empis tesselata F., sh. 5. VII. 95, 800 ft. Bibionidae : (10) Bibio pomonae F., ? fp. n. VII. 96, 700 ft. Cordyluridae : (n) Scatophaga maculipes Zett., ? fp. 2. VII. 95, 800 ft. 125. Lotus corniculatus, Linn. [Lit. Brit. 23 , 34 ; Farrer 653 ; N.CE. 1 , 3 b, 11 , 12 , 14 , 14 a, 15 , 16 , 18 , 21 b, 25 , 30 , 32 , 33 , 34 ; Warnstorf 2507 ; Alps 2 , 9 , 16 , 34 ; Pyren. 17 ; Medit. 34 .] A Bombus-flower, fertilized at Clova by B. lap- ponicus and B. agrorum. The butterflies, which visit, are to it robbers. The tongue of Apis is hardly long enough to reach the honey. Kerner speaks of dark-coloured flowers occurring at high levels ; once we found such at 2,400 ft. Visitors. Lepidoptera. Rhopalocera : (1) Argynnis aglaia L., sh. 23. VI. 95, 900 ft. once. (2) Lycaena icarus Rott., sh. 22. VI.-8. VII. 95, 18. VI.-10. VII. 96, 7-1,000 ft., the male much more freq. than the female. Heterocera : Geometridae : (3) Fidonia atomaria L., 15. VI. 99, 1,100 ft. (4) Another sp. 15. VI. 99, 12-1,500 ft. Hymeno- ptera. Aculeata: Apidae : (5) Apis mellifica L., sh. 16. VI. 95, 700 ft. (6) Bombus terrestris L., sh. 1-8. VII. 95, 800 ft. (7) B. pratorum L., 26. VI. 95, 800 ft. (8) B. lapponicus F., cp. and sh. 26. VI.-i. VII. 95, 22. VI.-10. VII. 96, 19. VI. 99, 8-2,300 ft. (9) B. lapi- darius L., sh. 6-1 1. VII. 96, 800 ft. (10) B. agrorum F., sh. and cp. 25. VI.-23. VII. 95, 14-15. VI. 99, 8-1,100 ft. (n) B. venustus Smith, sh. 16. Vl.-n. VII. 96, 700 ft. (12) B. hortorum L., sh. 15. VI. 99, 800 ft. Petiolata tubulifera: Vespidae : (13) Odynerus pictus Curt., 25. VI. 95, 800 ft. Diptera. Tachinidae\ (14) Siphona geniculata Deg., seeking h. 16. VI. 99, 800 ft. Mus- cidae : (15) Calliphora sp., seeking h. 15. V. 95, 900 ft. Anthony iidae : (16) Hyetodesia incana W., 22. VI. 95, 800 ft. (17) Drymia hamata Fin., 26. VI. 96, 2,300 ft. 126. Oxytropis campestris, DC. [Lit. Arct. 7 ; Alps 2 , 16 . ] The flower is usually creamy white with two yellow Insects in Great Britain. 553 patches on the standard and a purple tip to the keel, not pure white as stated in Trans. Bot. Soc. Edin., xviii. 391 ; but it is whiter and larger than the usual form of the Eastern Alps. The colour varies from this creamy white to a pale lemon- yellow or a pale violet. The flower has a sweet scent and abundant honey. The calyx-tube is 7 mm. long, and its teeth an additional 2 mm., and is rather thin, so that it offers but little resistance to the insects which rob the honey by biting through it. The narrow part of the flower is 10 mm. long. The passages to the honey between the bases of the stamens are very long. The stigma stands 1 mm. above the stamens, and is touched by its own pollen. Rubbing appears to be necessary to make it receptive. The rough areas on the petals, which afford a foothold to insects, have been fully described by Loew for O. pilosa (Flora, 1891, p. 84). In plants from Clova they are distributed as follows : standard very smooth below, less so above on the inner face ; wings very rough on the surface directed upwards, especially towards the interlocking processes ; keel slightly rough on both sides towards the tip, perfectly smooth below, and rather smooth along the middle line. The plant fruits very freely. Visitors. Hymenoptera. Aculeata : Apidae\ (1) Bombus lap- ponicus F., sh. 26. VI.-2. VII. 96, 2,300 ft. Formicidae : (2) Formica fusca Latr., seeking h. 26. VI. 96, 22-2,300 ft. Petiolata parasitica : (3) 1 sp., seeking h. 26. VI. 96, 2,200 ft. Diptera. Bibionidae\ (4) Scatopse sp., fp. 26. VI. 96, 22-2,300 ft. Anthomyiidae\ (5) Limno- phora solitaria Ztt., seeking h. 26. VI. 96, 2,200 ft. Sapromyzidae : (6) Sapromyza sp., seeking h. 2. VII. 96, 2,300 ft. Coleoptera. (7) Meligethes aeneus F., seeking h. 2. VII. 96, 2,300 ft. (8) M. viri- descens F., fp. 26. VI. 96, 22-2,300 ft. Thysanoptera. (9) Thrips sp., 22. VI.-2. VII. 96, 22-2,300 ft. very ab. 127. Vicia Cracca, Linn. [Lit. Brit. 23; N.C.E. 1, 3 b, 8, 14, 18, 21 b, 32, 33, 34, 40 ; De Vries 2460 ; Arct. 36 ; Alps 2, 9, 16, 21 b ; Pyren. 17.] A Bombus-flower with honey attainable to all the Bombi, but not readily to Apis ; rare at Clova. The calyx is sometimes bitten through. The tubular part of the flower is 5-6 mm. long. 554 Willis and Bur kill. — Flowers and Visitors. Hymenoptera. Aculeata : Apidae : (i) Bombus terrestris L.j sh. ii. VII. 9 6, 700 ft. Diptera. Sarcophagidae : (2) Sarcophaga sp., sh. through boring in the calyx, 11. VII. 96, 700 ft. 128. Vicia sylvatica, Linn. [Lit. Brit. 23 .] The flowers are so massed together that the plant is very conspicuous, and there is a sweet scent. The petals are veined with mauve. The stigma projects a trifle beyond the anthers, and the style has a long brush of sweeping hairs. If rubbed the stigma leaves a sticky streak, and does not become self-fertilized in the absence of insect visitors. Hence the mechanism of the flower seems to be that suggested for the genus by H. Muller. The petals are 16-18 mm. long, and the narrow part of the flower 10-12 mm. The honey is secreted in the position usual for the genus. We have seen the calyx with a hole bitten through it. Schulz, in error, states that Darwin observed bees to bite through the calyx ; the plant referred to is, however, Lathyrus sylvestris. Scott Elliot observed Bombus muscorum and B. hortorum as visitors. Visitors. Hymenoptera. Aculeata: Apidae : (1) Bombus lap- ponicus F., seeking h. and cp. 10. VII. 96, 2,300 ft. Petiolata tubuli- fera : Vespidae : (2) Odynerus sp., sh. through borings in calyx, 10. VII. 96, 2,300 ft. Diptera. Bibionidae'. (3) Dilophus albipennis Mg., sh. through borings in calyx, 26. VI. 96, 2,300 ft. Anthomyiidae : (4) 1 sp., seeking h. 2. VII. 96, 2,300 ft. Sapromyzidae : (5) Sapromyza sp., sh. through borings in calyx, 10. VII. 96, 2,300 ft. Coleoptera. (6) Meligethes viridescens F., 26. VI. 96, 2,300 ft. (7) M. aeneus F., seeking h. 10. VII. 96, 2,100 ft. Thysanoptera. (8) Thrips sp., 26. VI. 96, 2,300 ft. 129. Vicia sepium, Linn. [Lit. Brit. 23 ; N.C.E. 1 , 3 b, 11, 16 , 18 , 21 b, 33 , 34 , 40 ; De Vries 2460 ; Alps 2 , 9 , 34 ; Pyren. 17 .] Vicia sepium is, as Muller points out, a Bombus- flower in which the honey is too difficult of access for Lepido- ptera, and to Bombus terrestris is most readily obtained by a biting through of the calyx. We have found bitten flowers at Clova ; and they have been noted abundantly by Muller, Schulz, Knuth, and Alfken in Germany, and by MacLeod in Insects in Great Britain . 555 Flanders. Myrmica rubra was seen (24. VI. 95) on the stipules apparently on account of the honey there. Visitors . Hymenoptera. Aculeata : Apidae : (1) Bombus venustus Smith, sh. Diptera. Anthomyiidae : (2) Hyetodesia incana W., seek- ing h. Sepsidae : (3) Sepsis cynipsea L., seeking h. All at 800 ft. 18. VI. 96. 130. Lathyrus pratensis, Linn. [Lit. Brit. 23 ; N.C.B. 1 , 3 b, 14 , 14 a, 18 , 21 b, 32 , 34 , 40 ; Arct. 36 ; Alps 2 , 34 ; Medit. 34 .] A bee-flower, but not freely visited. Fertiliza- tion is, however, dependent on insect visits. Visitors. Hymenoptera. Aculeata : Apidae : (1) Apis mellifica L., sh. 1 1. VII. 96, 700 ft. once. Diptera. Anthomyiidae : (2) An- thomyia sp., fp. 4-5. VII. 95, 800 ft. Hemiptera. (3) Anthocoris ? nemorum L., seeking h. 16. IX. 95, 900 ft. 131. Lathyrus macrorrhizus, Wimm. [Lit. Brit. 23 ; N.C.E. 14 , 21 b, 34 , 40 ; Loew 1358 ; Pyren. 17 .] A Bombus- flower needing insect aid for fertilization, and, as it is not freely visited by insects, commonly sterile. Visitors. Lepidoptera. Rhopalocera : (1) Pieris napi L., sh. 10. VI. 99, 700 ft. Hymenoptera. Aculeata : Apidae : (2) Bombus lapidarius L., sh. 21. V. 96, 800 ft. (3) B. agrorum F., 1. VI. 97, 19. VI. 99, 800 ft. Diptera. Anthomyiidae : (4) Anthomyia sul- civentris Ztt., seeking h. 24. V. 97, 800 ft. 132. Polygala vulgaris, Linn. [Lit. Brit. % Hart. 933 ; N.C.E. 1 , 3 b, 14 , 18 , 21 b, 34 ; Pyren. 17 .] Poly gala vulgaris is another neglected bee-flower. Apis and Bombi are recorded — the one or the other — as frequent visitors by Muller in Germany, by MacLeod in the Pyrenees, and (to P. deprena) by MacLeod in Flanders ; both have been observed on P. vulgaris by Knuth in the North Friesian islands. At Clova spontaneous self-fertilization is the rule. Self-fertilization likewise is common on the Continent. At Clova the wings are usually bright blue, and, when the flower is open, 7 mm. long. A tongue 4 mm. long is sufficient to reach the honey. Visitors. Diptera. Muscidae : (1)1 sp., 6. VII. 94, about 2,000 ft. 556 Willis and Bur kill. — Flowers and Class H § 23. Digitalis Type. 133 . Digitalis purpurea, Linn. [Lit. Brit. 23, 39 ; Ogle 1904 ; Darwin 482 ; N.C.E. 1 , 4, 21 b, 30, 32, 33, 34 ; Alps 9.] Bees and beetles visit this plant. Contabescence was observed. Visitors. Hymenoptera. Aculeata: Apidae : (1) Bombus ter- restris L., sh. 25. IX. 95, 800 ft. and ? 29. VI. 95, 1,100 ft. (2) B. agrorum F., cp. and sh. 5. VII. 95, 800 ft. once. (3) B. venustus Smith, sh. 18. VI. 96, 800 ft. once. Diptera. Anthomyiidae : (4) Drymia hamata Fin., 25. VI. 95, 800 ft. (5) Anthomyia sp., seeking h. 21. IX. 95, 800 ft. Coleoptera. (6) Meligethes viridescens F., 2. VII. and 21. IX. 95, 800 ft., 29. VI. 96, 11-1,500 ft. freq. Thy- sanoptera. (7) Thrips sp., sh. 21. VI. 96, 1,500 ft. 134 . Mimulus Langsdorffii, Donn. (M. luteus , auctorum anglorum). [Lit. N.C.E. 1, 9 ; Batalin 147.] Self-pollination occurs in the fall of the corolla by the anthers sliding up the style to the stigma. The stigma is very sensitive. The flower is obviously suited to Bombus-like insects ; but the throat is rather low for our British Bombi. We have not seen them to visit. Visitors. Diptera. Anthomyiidae'. (1) Anthomyia sp., sh. 22. VI. 96, 800 ft. Class H § 24. Erica Type. 135 . Arctostaphylos Uva-ursi, Spreng. [Lit. N.C.E. 34; Arct. 36, 37 a ; Alps 2 , 9 ; Pyren. 17.] As the snows melt the young inflorescences can be found in the newly cleared patches of ground. The first flowers open in early May, and at mid May the plant is in full flower. These flowers are strongly scented, and are entirely visited by Bombi, chiefly B. lapponicus, which runs along the ground eagerly from bunch to bunch, sucks hanging back downwards, and then flies or crawls off to another plant. A bee, probably Bombus terrestris, often bites the corolla. Seed is freely formed, and ripens in September. Visitors. Hymenoptera. Aculeata: Apidae : (1) Bombus terres- Insects in Great Britain . 557 tris L., sh. 20-23. V. 97. 15-1,900 ft. not infreq. (2) B. lapponicus F., sh. 20-23. V. 97, 8-1,900 ft. ab. 136 . Vaccinium myrtillus, Linn. [Lit. Brit . 23, 29, 39 ; Ogle 1905; N.C.E. 1, 4, 16, 18, 33, 34, 40; Arct. 34, 36; Alps 2, 34 ; Pyren . 17.] A very typical bee-flower, attracting Bombus lapponicus in great quantity and other Bombi also. The honey is particularly abundant, and drops appear on the bell within the reach of insects which cannot obtain it from the nectary. Fruit may ripen very abundantly. Visitors. Lepidoptera. Heterocera : Geometridae\ (1) Larentia salicata Hb., sh. 25. VI. 95, 2,300 ft. twice. Hymenoptera. Acu- leata: Apidae\ (2) Bombus terrestris L., sh. 16. VI.-17. VII. 95, 22- 23. V. 96, 18-27. V. 97, 12. VII. 99, 7-2,300 ft. (3) B. pratorum L., sh. 19. VI. 95, 2,000 ft. (4) B. lapponicus F., sh. 16-25. VI. 95, 18-25. V. 97 > I2 - VI* 99) 7-2,400 ft. very ab. (5) B. hortorum L., sh. 17. VI. 99, 2,500 ft. Formicidae\ (6) Formica fusca Latr., seeking h. 18. V. 97, 1,900 ft. and inside a flower, the edge of which had been eaten, 12. V. 98, 800 ft. Diptera. Empidae\ (7) Empis lucida Ztt., 24. V. 97; 12. VI. 99, 1,600-2,300 ft. Anthomyiidae : (8) Anthomyia sulciventris Ztt., seeking h. 25. VI. 95, 2,300 ft. 137 . Vaccinium Vitis-idaea, Linn. [Lit. Brit. 23, 26 ; N.C.E. 14, 33, 34, 40; Arct. 7, 36, 37 a, 38; Alps 2, 9.] Bees and hemitropous flies visit this flower. Fruit is set abundantly. Visitors . Lepidoptera. Heterocera: Noctuidae : (1) Triphaena sp., 19. VI. 95, 2,000 ft. Hymenoptera. Aculeata : Apidae : (2) Bombus terrestris L., sh. 24. IX. 95, 1,200 ft. (3) B. lapponicus F., sh. 19-27. VI. 95, 20-2,100 ft. (4) Nomada ruficornis L., sh. 12. VI. 99, 1,000 ft. Diptera. Syrphidae'. (5) Melanostoma quadri- maculatum Verrall, sh. 19. VI. 95, 2,000 ft. Empidae'. (6) Empis lucida Ztt., 19. VI. 95, 13. VI. 99, 19-2,000 ft. (7) E. livida L., sh. 19. VI. 99, 2,000 ft. 138 . Erica Tetralix, Linn. [Lit. Brit. 23, 29, 34, 39 ; N.C.E. 1 , 3 c, 11, 12, 14, 14 a, 18, 21 a, 30, 35, 40.] Bombi are the chief visitors. By flowering just after midsummer, when butterflies are numerous, it obtains a certain number 558 Willis and Bur kill. — Flowers and of visits from them. Apis visits it freely. A species of Bombus, probably B. terrestris, bites through the corolla. Abnormally, more or less polypetalous flowers (such as Sigerson described in Proc. Royal Irish Acad., 1871, Ser. II, vol. i, and Price in Proc. Bot. Soc. Edinb., xi, p. 256) are not uncommon in certain seasons. Visitors. Lepidoptera. Rhopalocera : (1) Argynnis selene Schiff., sh. 23. VI. 95, 900 ft. (2) A. aglaia L., sh. 15-25. VI. 95, 1. VII. 96, 9-1,000 ft. (3) Polyommatus phloeas L., sh. 1. VII. 95, 800 ft. Heterocera: Nocluidae : (4) Celaena haworthii Curt., sh. 23. IX. 95, 1,100 ft. Geometridae : (5) Cidaria sp., sh. 2. VII. 95, 1,100 ft. Hymenoptera. Aculeata : Apidae : (6) Apis mellifica L., sh. 17-21. VII. 95, 9-1,200 ft. (7) Bombus terrestris L., sh. 23. VI.-23. IX. 95, 22. VI.-9. VII. 96, 8-1,400 ft. ab. (8) B. lapponicus F., sh. 23. VI.-19. IX. 95, 8-10. VII. 96, 8-1,500 ft. (9) B. jonellus Kirby, cp. and sh. 21-22. VII. 95, 11-1,200 ft. (10) B. agrorum F., sh. 5. VII. and 23. IX. 95, 8-900 ft. (n) B. venustus Smith, sh. 22. VI. 95, 1,100 ft. Vespidae : (12) Vespa norvegica F., sh. by means of borings, 21-22. VII. 95, 11-1,200 ft. Diptera. Syrphidae'. (13) Eristalis pertinax Scop., 20. IX. 95, 9-1,000 ft. Muscidae : (14) Pollenia rudis F., sh. and fp. 22-23. IX. 95, 9-1,110 ft. Antho- myiidae : (15) Hyetodesia incana W., 20. IX. 95, 9-1,100 ft. Orta - lidae\ (16) Pteropaectria frondescentiae L., seeking h. 6. VII. 95, 900 ft. Coleoptera. (17) Meligethes viridescens F., sh. by means of a boring, 23. IX. 95, 1,100 ft. 139. Erica cinerea, Linn. [Lit. Brit. 23 , 26 , 29 , 34 , 39 ; Ogle 1905 ; Powell 2020 ; N.C.E. 14 , 14 a, 15 , 16 , 18 , 21 a, 21 b.] Apis visits this plant more freely than it does E. Tetralix. Bombi are however the chief visitors, one of them, B. terrestris, often bites through the corolla in order to obtain the honey. Vespa and other short- tongued insects afterwards take advantage of the borings. Visitors. Lepidoptera. Rhopalocera: (1) Argynnis aglaia L., sh. 18. VI. 96, 800 ft. (2) A. selene Schiff., sh. 23. VI. 95, 900 ft. (3) Coenonympha pamphilus L., sh. 26. VI. 95, 800 ft. (4) Polyom- matus phloeas L., sh. 15. IX. 95 and 18. VI. 96, 800 ft. Hymeno- ptera. Aculeata: Apidae : (5) Apis mellifica L., sh. 17-22. VII. 95, Insects in Great Britain. 559 9-1,200 ft. freq. (6) Bombus terrestris L., sh. in the proper manner and biting through, 23. VI.-24. IX. 95, 18. VI.-9. VII. 96, 8-1,700 ft. very ab. (7) B. jonellus Kirby, sh. 21-22. VII. 95, 11-1,300 ft. (8) B. lapponicus F., sh. 25. VI.-14. IX. 95, 18. VI.-io. VII. 96, 8-2,300 ft. freq. (9) B. smithanus White, 14. IX. 95, 800 ft. (10) B. pratorum L., sh. 27. VI. 95, 800 ft. (11) Psithyrus quadricolor Lep., sh. 22. VII. 95, 1,700 ft. Vespidae : (12) Vespa norvegica ? F., sh. by means of borings, 21. VII. 95, 11-1,200 ft. twice. Diptera. Syrphidae : (13) Volucella bombylans L., sh. 23. VI. 95, 900 ft. once. Muscidae : (14) Pollenia rudis F., sh. by means of a boring, 14. IX. 95, 900 ft. once. Class H § 25. Simple Pendulous Type. 140. Geranium phaeum, Linn. [Lit. Brit., Darwin 482 ; N.C.E. 1 , 21 b, 33 , 34 ; Errera 633 ; Loew 1358 ; Pyren. 17 .] Errera found it in Belgium to be a very characteristic bee- flower. At Clova Bombus agrorum is a regular visitor, but Syrphids are not infrequent. Visitors. Lepidoptera. Heterocera : Noctuidae : (1) Habrostola urticae Hb., sh. 14. VI. 99, 800 ft. Tineidae : (2) Gelechia sp., sh. 26. VI. 95. Hymenoptera. Aculeata : Apidae : (3) Bombus agrorum F., sh. 16-21. VI. 95, 10-12. VI, 99, fairly constant. (4) B. terrestris L., sh. 22. VI. 96, 12. VI. 99. Petiolata tubulifera : Vespidae : (5) Odynerus trimarginatus Ztt., sh. 22. VI. 96. Diptera. Syrphidae : (6) Platychirus manicatus Mg., sh. 10. VI. 99. (7) Rhingia campestris Mg., 17. VI. 96. Empidae : (8) Empis sp., sh. 22. VI. 96. (9) E. punctata Mg., 22. VI. 96. TacJdnidae : (10) Siphona geniculata Deg., sh. 18. VI. 96. Anthomyiidae : (1 1) An- thomyia sp., sh. 19-22. VI. 96. All at 800 ft. 141. Prunus avium, Linn. [Lit. N.C.E. 1 , 3 b, 16 , 18 , 33 .] This tree is very well visited by Bombus lapponicus. Visitors. Lepidoptera. Rhopalocera : (1) Pieris rapae L., sh. 22. VI. 97, 600 ft. (2) Vanessa urticae L., sh. 21. V. 97, 600 ft. Hymenoptera. Aculeata : Apidae : (3) Apis mellifica L., sh. 21. V. 97, 800 ft. (4) Bombus lapponicus F., 21-25. V. 97, 800 ft. freq. Diptera. Syrphidae : (5) Syrphus punctulatus Verrall, sh. 21. V. 97, 560 Willis and Burkill. — Flowers and 800 ft. (6) P. discimanus Lw., fp. 21. V. 97, 800 ft. Empidae\ (7) Rhamphomyia cinerascens Mg., sh. 24. V. 97, 800 ft. Anthomyiidae : (8) Anthomyia sulciventris Ztt., 21-25. V. 97, 6-800 ft. Thysano- ptera : (9) Thrips sp., in base of the flower, 16. V. 98, 800 ft. 142. Rubus Idaeus, Linn. [Lit. Brit. 23; N.C.E. 1, 16, 18, 32, 34, 40; MacLeod 1473; Alps 2, 9.] We found moths frequent visitors ; MacLeod observed the same in Belgium. Visitors. Lepidoptera. Heterocera: Bombycidae\ (1) Hepialis humili L., sh. 27. VI.-3. VII. 955, 800 ft. Noduidae : (2) Apamea gemina Hb., sh. 27. VI. 95, 800 ft. (3) Dianthecia cucubali Fues., sh. 24-27. VI. 95, 800 ft. (4) Xylocampa areola, Esp., sh. 27. VI. 95, 800 ft. (5) Habrostola tripartita Hufn,, sh. 27. VI. 95, 800 ft. (6) Plusia chrisitis L., sh. 27. VL-6. VII. 95, 800 ft. (7) P. festucae L., sh. 27. VI. 95, 800 ft. (8) P. pulchrina Haw., sh. 27-30. VI. 95, 800 ft. Geometridae : (9) Cabera pusaria L., sh. 27. VI. 95, 800 ft. (10) Thera variata Schiff., sh. 27. VI. 95, 800 ft. Hymenoptera. Aculeata: Apidae\ (11) Apis raellifica L., sh. 20-23. VI. 95, 800 ft. (12) Bombus terrestris L., 27. VI. 95, 800 ft. (13) B. pratorum L., 27. VI. 95, 800 ft (14) B. lapponicus F., sh. 3-6. VII. 96, 21- 2,300 ft. (15) B. agrorum F., sh. 20. VI-2. VII. 95, 19. VI. 99, 800 ft. freq. Vespidae : (16) Vespa norvegica F., sh. 29. VI. 96, 800 ft. (17) Vespa sylvestris Scop., 27. VI, 95, 800 ft. Diptera. Syrphidae : (18) Sericomyia lapponum L., sh. 23. VI. 95, 800 ft. (19) Eristalis arbustorum L., sh. 23. VI. 97, 800 ft. Anthomyiidae : (20) Hyetodesia incana W., sh. 21-23. VI. 95, 26. VI. 96, 8-1,000 ft. (21) Anthomyia sp., sh. 23. VI. 95, 800 ft. (22) Hydrotaea sp., sh. 19. VI. 99, 800 ft. 143. Getim rivale, Linn. [Lit. Brit. 23 ; N.C.E . 1, 16, 21a, 21 b, 33, 34 ; Warnstorf 2507 ; Arct. 34 ; Alps 2, 9.] Visitors. Hymenoptera. Aculeata: Apidae : (1) Bombus lappo- nicus F., sh. 6. VII. 95, 20. VI.-6. VII. 96, 23-2,500 ft. (2) B. agrorum F., sh. 24. VI. 95, 800 ft. (3) Psithyrus quadricolor Lep., sh. 20. VI. 96, 2,400 ft. Diptera. Anthomyiidae'. (4) Anthomyia sp., fp. 6. VII. 96, 2,400 ft. Coleoptera. (5) Meligethes viridescens F., sh. 20. VI. 96, 2,400 ft. Insects in Great Britain. 561 Class H § 26. Pyrola Secunda Type. 144 . Pyrola secunda, Linn. [Lit. N.C.E. 1 , 4, 34 ; Alps 9.] The stigma protrudes from the opening bud, and the stamens seem to force their way between the petals. The openings of the anthers are turned away from the stigma. Visitors . Hymenoptera. Aculeata : Apidae'. (1) Bombus lappo- nicus F., sh. Coleoptera. (2) Meligethes aeneus F., fp. (3) Epu- raea aestiva L., ? fp. All 6. VII. 96, 1,900 ft. 145 . Ribes sanguineum, Pursh. [Lit. Brit. 29 ; N.C.E. 3 a, 40.] In cultivation. Visitors. Hymenoptera. Aculeata: Apidae : ( 1 ) Bombus terres- tris L., sh. 14. V. 98, 800 ft. Class H § 27. Galanthus Type. 146 . Galanthus nivalis, Linn. [Lit. N.C.E. 1 , 9, 18, 33, 34 ; Knuth 2871.] In cultivation. Visitors. Hymenoptera. Aculeata: Apidae'. (1) Apis mellifica L., 15. IV. 95, 800 ft. Class H § 28. Campanula Type. 147 . Campanula rotundifolia, Linn. [Lit. Brit. 23, 34, 39 ; Marquand 1513; N.C.E. 1 , 11, 14, 14 a, 16, 18,30,32,34, 35 ; Arct. 36, 38 ; Alps 2, 34 ; Pyren. 17.] A flower in a measure specialized for Melitta, Eriades, and Halictoides, and a shelter-flower to small flies, which are abundant in its bells, and also sometimes a shelter-flower to Andrena. Bombi, Apis, Melitta, Cilissa, Eriades, Halictoides, and other similar bees visit the flower in Germany and the Alps ; Bombi have been seen on it in Scandinavia and the Pyrenees, and Bombus terrestris in Southern Scotland ; it is worth remark that we have seen no bees in the flowers except two species of Andrena. Insects with a tongue of 3 mm. and upwards can reach the honey. Visitors. Lepidoptera. Heterocera : Pyralidae : (1) Scopula alpi- TABLE XX. Individuals visiting the different species. 562 Willis and Bur kill. — Flowers and OOOVD N OVOO rt- ro - S , ^ cj « d eS 3 K .2 .2 Cj X too > r 3 Oh o ; 8 a S ■; l »l ° S' w OhO+j_ m ^ <0 £} 3 3 g 3 .2 1 OOOOO^OO ^ *T3 f ~n\ £T .... ^ O 3 3 £ ci *"3 too jj .« r» S rf w rt too «« G Oh {3 O -00 ON O >-> cif ro tJ- iriVO x-00 ov ChG\OVO\C\CVCM^OlOOOUOOOOOOHHHHHHHHHH Insects in Great Britain . 563 VO Q -T- « O VO d Mh « osoo O CO co i>. m M -<*- 1>. o -<$* Cl i>»0Q CO 0 «M w # to « tHK) noo H H # 1 ^. 1 ^. 0 10 s 1 11 11 00 . 1 " I " 1 1 ^ 1 M 1 1 1 1 M II- 1 i I 00 00 Os 00 N 1 M 1 1 1 vC | ^ 1 1 | 1 ^ i 1 |j l M | | | 1 M 2 | 1 1 VO ON O CO VD O . -+H N ■tlflH CO | M CO Cl Cl M C!m.i1 i '^-MV©VOM.-i i . . * II M III os on Cl rf* OO ON M " i I 1 " 1 1 1 1 11 1 1 1 II 1 1 1 VO ON vo tH ON CO 1 1 1 1 i M 11 1 1 1 1 1 11 r 1 11 11 M 1 11 m Th J>* 1 1 1 1 11 1 1 1 1 I 1 1 II 1 II M - II 11 1 I 00 CO vo 1 1 1 1 ■"* 1 1 l ti VO VO X-. 6 1 1 1 1 r 1 1 1 11 1 1 1 1 11 r 1 1 1 « 1 11 1 1 VO OS ON « 1 1 1 1 1 e-i | MINI i i -'111111111 1 l VO 1 11 1 1 1 - 1 1 1 1 1 1 1 1 1 1 II 1 1 1 1 1 1 1 1 e* CO O 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 m 1 I I 1 1 1 i 1 m l 1 h 1 1 .1 1 iB 1 1 h 11 h 1 1 1 11 1 VO O CO CO M M >0 > o e < 0 00 Cl | Cl M Tj- M WM Tt- VO, +0 + tO W CO VO OO CO m 1 | j -oo do h ci tovo Cl ci c< « ei d Cl ci ci Cl rOfOfOrOffJWfOfOfOcO'+'+'ti-i-'t't't Qq 1 Denotes that we have records of visitors but not at times when we were keeping count of individuals. 564 Willis and Burkill. — Flowers and nalis Schiff., sh. 27. VI. 95, 2,000 ft. once. Tineidae : (2) Glyphi- pteryx fuscoviridella Haw., sh. 27. VI. 95, 800 ft. once. Erioce- phalidae\ (3) Eriocephala calthella L., 23. VII. 95, 800 ft. Hymen o- ptera. Aculeata: Apidae\ (4) Andrena analis Panz, cp. 17. VII. 95, and sh. 10. VII. 96, 800 ft. (5) A. coitana Kirby, sh. freq. and sheltering (?), 2-23. VII. 95, 800 ft. Petiolata parasitica: Cynipidae : (6 and 7) 2 spp., 16. VI. and 23. VII. 95, 800 ft. Diptera. Syr - phidae\ (8) Rhingia campestris Mg., sh. 10. VII. 96, 800 ft. once. (9) Platychirus manicatus Mg., sh. 3-17. VII. 95, 800 ft.; 8. VII. 96, 2,400 ft. (10) Melanostoma mellinum L., 3. VII. 95, 800 ft. Tachi- nidae : (n) Siphona geniculata Deg., sh. 26. VI. 95; 13-16. IX. 95, 7-800 ft. Muscidae : (12) Calliphora erythocephala Mg., sh. 10. VII. 96, 800 ft. Anthomyiidae\ (13) Drymia hamata Fin., fp. 2. VII. 96, 2,100 ft. (14) Anthomyia sp., 16. VI.-23. VII. 95, 8-1,800 ft. (15) Trichophthicus hirsutulus Ztt., 6. VII. 96, 2,000 ft. (16) Tri- chophthicus sp., sh. and fp. 17-23. VII. 95, 800 ft. Thysanoptera. (17) Thrips sp., sh. 22. IX. 95, 800 ft. We have had under observation the following flowers of Classes F and H, but have seen no insects visiting them : — Polygala serpyllacea , Weihe, Anthyllis vulneraria , Linn., Rubus saxatilis , Linn., Vaccinium uliginosum , Linn., Gentiana campestris , Linn., Rhinanthus Crista-galli , Linn., Habenaria albida , R. Br. ; however, from the last-named the pollinia were observed to be regularly removed at night. We have seen in flower at Clova,.but have not had suitable opportunities for watching : Lobelia Dortmanna , Linn., Primula veris , Linn. } and Utricularia minor , Linn. Silene Cucubalus, Wibel, Vicia hirsuta , Koch, Arctostaphylos alpina , Spreng., and Scrophularia nodosa , Linn., are other Clova plants of Class H which we have not seen in our district, although we have every reason to believe that they have been observed. Symphytum officinale , Linn., we have observed just outside our limits at 500 feet to be diligently visited by Bombus agrorum. Out of the whole available anthophilous insect-fauna of (for the time of our observations) 17,306 individuals, 1,507 went to Insects in Great Britain . 565 Classes F and H. It is not worth while to separate the two classes here ; for there are but three species assigned to F, and of them only one ( Silene acaulis) appeared as a true Lepidoptera-flower. The species of plants obtained attention as in Table XX. The decidedly desirable insects showed their marked preference ; and nearly one half of the total number of individuals of them, which we observed to visit, went to flowers of these two classes, and made 57*73 P er cent * of their visitors. TABLE XXI. Available. F and H. No. % No. % Distinctly desirable Desirable .... Indifferent . . . Injurious .... L 7 6 3 1 » 2 77 12,993 L 273 10.19 7-37 75.08 7.36 870 87 413 *37 57*73 5-77 27.4 1 9-°9 We found that in Class B' the blue-lilac flowers attracted the best of the insects, that the rose-purple came next, that yellow followed, and that white or eyed flowers came last. Experience with Classes F and H is different, and our figures are as follows: with white at the top, rose-purple second, yellow third, and lilac-blue last. TABLE XXII. Lilac and blue. Rose and purple. Yellow and scarlet. White. Decidedly desirable Desirable .... Indifferent . . . Injurious .... 16.66 12-35 60.31 10.67 74.67 5*95 16.50 2.88 46-26 I.77 32-75 19.22 76-55 7.24 15.86 •34 In the table which follows and which amplifies XXI, we have kept Campanula apart, for it certainly is a peculiar type ; Q q 2 566 Willis and Bur kill. — Flowers and but still the lilac-blue flowers remain those which get fewest of the decidedly desirable insects. TABLE XXIII. Apis- Bomb. B ffi Phyt. Entom. Ants. Wasps, Lep.l. Lep.m. Lep.s s p < A Q 15 U d W Campanula 12.82 I * 7 I _ I - 7 I •85 4.27 63-25 _ 15-39 Other blue-lilac flowers . i -45 13.04 i -45 — — 18-84 i -45 2.90 2- 90 44-93 8.70 4-35 Rose-purple 12.09 54-13 .19 •38 2.30 8.45 •77 — 4.99 7-10 7-10 2.50 Yellow 17.24 19.02 •39 .98 - 10-00 .20 • 20 i -1 8 25.69 6-86 18.24 White 27*93 30-00 •34 I.03 1862 — — 6-90 8.97 5.86 •34 In our enumeration of visitors, and in Table XX, we have taken the flowers of Class H in such order that first come those with erect actinomorphic flowers, secondly those with horizontal zygomorphic flowers, and thirdly, those with pendent actinomorphic flowers. We may add to them the three flowers of Class F — one erect actinomorphic and two horizontal zygo- morphic — whereupon we get : — 1. Six erect actinomorphic in which to reach the honey a tongue 4-16 mm. long is required, average 10 mm. 2. Thirty-eight horizontal zygomorphic in which to reach the honey a tongue 4-20 mm. long is required, average 8 mm. 3. Thirteen pendent actinomorphic in which to reach the honey a tongue 1-7 mm. long is required, average 4-5 mm. It is very easy to show that a greater exclusion of the undesirable or little desirable insects is effected by the simple inversion of the flower than by lengthening the tube. TABLE XXIV. Effect of the position of the flower upon the groups of the visitors. Apis. Bomb. s a Entom. Phyt. Ants. Wasps. Lep.l. Lep.m, Lep.s. S Q C/3 Q 0 O d w Erect . . . _ 5-10 _ 25 - 5 1 3-06 — 8.16 27'55 23-47 7.14 Horizontal . 23-57 I9.OI •39 .65 — 964 .26 •39 2.29 22.01 7.81 13.28 Pendent . . 8.11 50-55 2.65 • 62 2-34 9-83 •47 .16 4-37 16.07 1.87 2.96 Insects in Great Britain . 567 TABLE XXV. Effect of the position of the flower upon the desirability of the visitors. Erect. Horizontal. Pendent. Decidedly desirable . Desirable .... Indifferent .... Injurious .... 30-61 11-22 51.02 7.I4 52.22 3-64 30.21 13-93 68.49 7-49 20.44 3-58 The pendent flowers thus, despite the shallowness of their honey, are seen to get the greater proportion of distinctly desirable insects, this proportion being chiefly made up by Bombi. It happens that the majority of the white flowers are pendent, all the lilac-blue flowers, except Campanula rotundi- folia , are horizontal, and most of the yellow flowers also, while the rose-purple flowers are divided. TABLE XXVI. Colour and position of flowers of Classes F and H. Lilac-Blue. Rose-Purple. Yellow-Scarlet. White. Erect . . O 4 2 O Horizontal *4 IO II 3 Pendent . I 5 I 6 But the observation recorded by means of Tables XXII and XXIII, that white and rose-purple flowers of Classes F and H get the best of the insects is, however, not entirely due to so many of the pendent flowers being white or rose-purple ; and if we take the horizontal flowers by themselves, the result remains the same, but the differences are somewhat lessened. By season the distinctly desirable insects get fewer towards autumn, the indifferent get a little fewer, while the desirable and injurious increase, especially the latter. 568 Willis and Bur kill, — Flowers and TABLE XXVII. Desirability of visitors to the various colours of the horizontal zygomorphic flowers. Lilac and Blue. Rose and Purple. Yellow and Scarlet. White. Decidedly desirable Desirable .... Indifferent . . . Injurious .... 33-33 5 - 8 ° 56 - 5 2 4-35 52.08 6.25 34-37 7.29 47.69 I- 8 9 29-83. 20.04 79-53 7-09 x 3-39 0-00 TABLE XXVIII. Visitors to Classes F and H by season. Spring. Summer. Autumn. No. % No. % No. % Distinctly desirable 2 1 1 65-94 605 56.23 54 48-65 Desirable .... IO 3 * 12 68 6-32 9 8.11 Indifferent . . . 93 29*06 291 27.04 29 26.13 Injurious .... 6 1.88 112 10.41 *9 1 7. 1 2 Total . . 320 - 1076 - hi - The actual numbers and percentages in the different groups are as follows : — TABLE XXIX. Visitors to Classes F and H by season. Apis. Bomb. a a Phyt. Entom. Ants. Wasps. Lep.l. Lep.m. Lep.s. 6 ft 03 ft c3 d H Total. ( \ Spring 62 I 4 I _ 2 _ 8 10 91 2 4 320 8 1 Summer 168 285 20 7 15 152 8 4 40 189 83 105 1076 H < - Autumn 3 49 “ 2 9 19 10 19 III V rt 1 f Spring 1-38 44.06 _ .62 _ 2.50 _ 3-i3 28.44 .62 1.25 C < | Summer i-6i 26.49 1.86 .65 i*39 I 4 ,I 3 •74 •37 3-7 1 I7-56 7.71 9.76 — § 1 V a, ( Autumn 2.70 44.14 1.81 8.11 17.12 9-01 17.12 Insects in Great Britain . 569 As the flowers of the classes under consideration set them- selves apart almost completely for the larger Apidae, we give here the seasonal distribution of these bees : — TABLE XXX. Seasonal distribution of Bees. The sequence is the sequence of their tongue-lengths. Name. Spring (23 days). Summer (88). Autumn (12). Total. Bombus hortorum 3 12 _ 15 B. agrorum .... 5 49 44 98 B. venustus .... — 9 — 9 B. smithianus . . . — 1 1 B. cognatus . . . — — 2 2 B. lapidarius . , . 3 — 3 6 B. lapponicus, with \ B. pratorum . . B. jonellus, and . ( 182 163 1 1 356 B. scrimshiranus . ) Psithyrus quadricolor — 10 1 11 Bombus terrestris . . 77 76 240 393 Bombi (unidentified) 2 43 1 46 Apis mellifica . . . 160 266 4 430 Total .... 432 628 3°7 1367 We may class these bees by their tongue-lengths : Bombus hortorum to B. cognatus first, B. lapidarius and B. lapponicus second, Psithyrus quadricolor and Bombus terrestris third, and Apis last. TABLE XXXI. Bees in season by their tongue-lengths. Spring. Summer. Autumn. Percentage Percentage Percentage No. of total No. of total No. of total insects. insects. insects. Tongue 15 mm. and over . 8 .19 70 .72 47 I.41 Tongue 10-15 mm. long . 185 4.41 163 I.67 H .42 Tongue 7-10 mm. long . . 77 I.83 86 .88 241 7* 2 5 Tongue 6 mm. long . . . 160 3-8 i 'V 266 2.72 4 .01 570 Willis and Bur kill, — Flowers and Insects . It remains now to compare our results with those of other observers, and the table which follows does this. As in the case of B' and A', we again find Muller’s observations very closely supported by those of Knuth, Verhoeff, Alfken and others on the coast of North Germany. Again we see the Alps showing an abundance of Lepidoptera, and our own country an abundance of short-tongued flies. F urther comment is reserved. TABLE XXXII. Comparison of species-visits to Clova flowers of Classes F and H in various parts of Europe. Apis. s' w W d, V i-l 6 Q Q ”3 O W Total. Clova (57 plants) 17 85 3 14 56 36 95 19 12 337 Germany — Muller . (35 ) 25 230 78 2 73 46 1 19 2 476 Flanders — MacLeod (25 ) IO 74 15 10 46 12 7 8 — 182 Friesian Coast — Knuth, Verhoeff, &c. . . (37 55 ) 23 293 66 8 54 32 12 6 I 495 Alps — Muller . . . ( 2 3 ;> ) 3 90 2 1 179 10 1 6 2 294 Pyrenees — MacLeod . (11 >> ) 41 2 — 21 9 1 1 “ 75 In conclusion, Classes F and B obtained the visits of Apis mellifica, of nine species of Bombi (all in the district except B. cognatus and B. scrimshiranus), of Psithyrus quadricolor, of two species of Andrena, of a Nomada, and two species of Odynerus, of two species of Vespa, of two kinds of ants, and of two species of ichneumons, of eight butterflies, of twelve of the Noctuid moths which are almost entirely crepuscular or nocturnal, of five geometers, of five ordinary Micro-lepidoptera, including Hepialis humuli, and also of Eriocephala calthella ; among Diptera, of thirteen Syrphidae including Rhingia campestris, of five species of Empis, of one Rhamphomyia, of four Muscids, of one Sarcophaga, and of Siphona geniculata, of eight Anthomyiids including Drymia hamata, of two Scatophagids, and of eleven other flies ; of six Coleoptera, of two Hemiptera, of Thrips and of a spider. Thus 109 species of insects visited the two classes, making 1,507 individual visits, the average constancy being 13-83. Observations on Gymnoascaceae. BY Miss E. DALE. With Plates XXVII and XXVIII. Introduction. I N May, 1901, Professor Marshall Ward handed to me for investigation three species of Gymnoascus , which had been received by him from Mr. Massee, who had collected them on the substrata referred to below. The species were (1) G. Reessii (Baranetzky), growing on dung, of what kind could not be determined ; (2) G. setosus (Eidam), on an old bee’s nest ; and (3) G. candidus (Eidam), Arachniotus candidus (Schroeter), on dead grass. Subsequent examination showed that all three species were growing together on the old nest. The total number of species of Gymnoascus actually known is probably about a dozen. Winter 1 , in Rabenhorst’s Krypto- gamen-Flora, describes G. Reessii, G. ruber, and G. uncinatus. Massee 2 mentions G. Reessii and G. ruber (van Tieghem), but does not notice any other species as found in Britain. Fischer 3 mentions five species, viz. G. Reessii, G. setosus (Eidam), G. durus (Zukal), G. umbrinus (Boudier), and G. Bour- queloti (Boudier). Saccardo 4 , in 1889, describes six species 1 Band I. 2. Pilze, p. 15 (1887). 3 British Fungus Flora, vol. iv, p. 18 (1895). 3 Engler und Prantl, Pflanzenfamilien, I. 1, p. 294 (1897). 4 Syll. Fung., vol. viii, p. 823 (1889). [Annals of Botany, Vol. XVII. No. LXVII. June, 1903.] 572 Dale . — Observations on Gymnoascaceae. of Gymnoascus , viz. G. Reessii , 6% ruber, G. aurantiacus (Peck), Sacc. ( Gymnascella aurantiaca , Peck), uncinatus (Eidam), (S', reticulatus (Zuk.), and G\ setosus (Eidam). In three later volumes he adds seven other species, viz. G. Zuffianus and G. EidamR ; G. Bourquelotii , ( 7 . tanbrinus , luteus , and G\ myriosporus 2 ; and ossicola 3 . During the present year (1902) a new species of Gymno- ascus has been described, but not figured, by Klocker 4 , under the name of G.Jlavus. Schroeter 5 , in treating of the Gymno- ascaceae in general, founded two new genera, Arachniotus and Amauroascus , by breaking up the original genus Gymno- ascus into three. He did not describe any new forms, but only reclassified those already known. Eidam’s Gymnoascus can- didus belongs to the genus Arachniotus , according to Schroe- ter’s classification, which has been generally adopted. It is the one which has been accepted by Matruchot and Dasson- ville, whose results, as will be seen later (page 590), appear to be confirmed by the work about to be described. Historical. The three species may first be considered briefly from the historical point of view. 1. Gymnoascus Reessii (Baran.) was first described in 1872 by Baranetzky 6 , who founded the genus on this species. He made cultures of the fungus, and worked out its life history in as great detail as was possible with the histological methods then available. His conclusions were afterwards disputed by subsequent workers, who, however, do not seem to have gone into the matter as thoroughly as Baranetzky. According to Baranetzky the fructifications are formed in the following manner : two swellings arise side by side on a single 1 vol. X, p. 71 (1892). 2 vol. xi, p. 437 (1895). 3 vol. xiv, p. 824 (1899). 4 Bot. Cent., Bd. lxxxix, No. 22, p. 626 (1902), and Hedwigia, Bd. xli, Heft 2, pp. 80-8 (1902). 5 Cohn’s Kryptogamen-Flora von Schlesien, Bd. iii, zweite Lieferung, zvveite Halfte, p. 210 (1893). See also Saccardo, 1. c., vol. xi, p. 438 (1895). 6 Entwickelungsgeschichte des Gymnoascus Reessii , Bot. Zeit., p. 145 (1872). Dale. — Observations on Gymnoascaceae. 573 hypha, one on each side of, and quite close to, a transverse wall. These swellings grow out into little branches, which twist spirally round one another and become club-shaped. At this stage Baranetzky observed that the two cells cannot be separated, but he says ‘ a true copulation does not occur since both cells remain completely closed. 5 They each become cut off by a wall from the hypha on which they arose. The free end of one cell swells, and becomes cut off by a transverse wall from the part below it. The other cell puts out from its free end a thin cylindrical projection, which is also cut off by a side wall. This cell gives rise to the ascogenous hyphae, and may therefore be called the ascogenous cell , while the other may be distinguished as the sterile cell. The cylindrical pro- jection lays itself round the swollen end of the sterile cell, and encircles it once by annular growth. It becomes segmented into almost isodiametric cells. Certain of these cells, generally not more than two, grow out into hyphae, which branch copiously without increasing much in length. In consequence there arise thick tufts with many short branches which swell at their ends and form asci. From the base of the sterile cell, meanwhile, grow out thin vegetative hyphae. The results of the work about to be described, in most of the essential points, confirm those obtained by Baranetzky, but, by the use of modern methods, they have been extended. In 1877 van Tieghem 1 described under the name Gymno - ascus ruber , a species which he compared with G. Reessii. His account of the development of the reproductive organs is very short, and he gives no figures. This species belongs to Schroeter’s genus Arachniotus. In 1883 Eidam 2 described G. Reessii as it occurred on a pupa of Sphinx Galii. He did not find the reproductive organs described by Baranetzky, but gives the origin of the coiled hyphae as follows : below the dividing wall of a my- celial hypha a lateral branch arises which coils closely round 1 (1) Sur le developpement de quelques Ascomycetes. Bull, de la Soc. Bot. de France, vol. xxiv, p. 159 (1877). 2 (1) Beitrag zur Kenntniss der Gymnoasceen. Cohn’s Beitrage, p. 267 (1883). 574 Dale. — Observations on Gymnoascaceae. the parent hypha or one which is adjacent. After winding round in a close coil for about eight or ten times it becomes loose and septate, and then grows out into branches which are the ascogenous hyphae. Eidam further states that Bara- netzky says the method of reproduction described by him only occurs in weak mycelia. I can find no such statement in Baranetzky’s paper ; in fact, he distinctly says that his cultures were perfectly normal and strong. Eidam 1 also cultivated G. ruber ( Arachniotus ruber), and in this species he found the kind of reproductive organs described by Baranetzky in G. Reessii , but only the early stages were described. Cell-fusion was not seen, although he sought specially for it, because he had already discovered it in Eremascus 2 . Perhaps the stages seen were too young, or the cultures not strong enough, as the ripe fructifications were never formed. In G. uncinatus , described by Eidam 1 as a new species, the early stages also agreed with Baranetzky’s account of G. Reessii. The fungus occurred spontaneously on sparrow-dung, but here again the ripe asci were not obtained in culture. In 1891 G. Reessii was again described by Brefeld 3 , who de- clares that the ascogenous hyphae arise from solitary branches, each of which coils itself into a spiral, from which the ascogenous hyphae are produced by branching. Baranetzky figures a few such solitary branches, but regards them as anomalous cases which do not develop farther. Brefeld confirms Baranetzky’s account of the formation of the asci on the ascogenous hyphae. 2. Gymnoascus setosus (Eidam) was first described by Eidam 4 as a new species at a meeting of the Botanical section of the Schlesische Gesellschaft fur vaterldndische Cultur , in January, 1882. Its habitat was an old wasp’s nest. Eidam, in a very 1 loc. cit. (1), p. 273. a (2) Untersuchungen iiber die Familie der Gymnoascaceen : Bericht iiber die Thatigkeit der bot. Section der Schlesischen Gesellschaft, p. 164 (1886). 3 (1) Ascomyceten, ii, Heft x, p. 158 (1891). 4 ( 3 ) Ueber Entwickelungsgeschichte der Askomyceten : Jahresbericht der Schlesischen Gesell., p. 175 (1883), and Bot. Cent., vol. x, p. 107 (1882). Dale. — Observations on Gymnoascaceae . 575 brief description, says that the mode of origin of the coil which precedes the formation of the asci is the same as in G. Reessii. No detailed life-history of this species has yet been given. 3. Gymnoascus candidus (Eidam) [Arachniotus candidus , Schroeter) was first described in 1886 by Eidam 1 , who gives an account of the mature fructifications as found by him grow- ing spontaneously on cooked rice. It was subsequently sepa- rated from Gymnoascus and placed in a new genus, Arach- niotus , by Schroeter 2 , who at the same time founded the genus A mauroascus on other species previously included in the genus Gymnoascus. The two new genera both agreed in having a peridium of very thin-walled, similar hyphae ; whereas, ac- cording to Schroeter’s limitations, Gymnoascus has a peridium of thick-walled hyphae which branch copiously and form a kind of trellis. Arachniotus differs from Amauroascus in having colourless, red, or yellow ascospores, while in Amauroascus the ascospore-wall is brown or brownish-violet. In the genus Arachniotus Schroeter places three species, Gymnoascus candidus (Eidam), G. ruber 3 (van Tieghem), and G. aureus (Eidam 4 ). Schroeter describes mature asci and conidia, but the life-history has not been worked out until now, as Eidam’s cultures were unsuccessful and he saw no conidia. Methods of Culture and Preparation. The three species were isolated by means of plate cultures, and the colonies thus obtained were transferred to one of the following culture media : — sterilized horse-dung in tubes, ex- tract of horse-dung in 2 per cent, agar-agar, or beer-wort in 2 per cent, agar-agar. The agar was sterilized in test-tubes. The most convenient method was found to be to grow, fix, and harden the fungus on the agar in the tube, as the species grew equally well on any of the media 5 . The material thus obtained was imbedded in paraffin, and the sections were 1 (2) loc. cit., p. 5 (1886). 2 loc. cit., p. 210. See also Saccardo, Syll. Fung., vol. xi, p. 438 (1895). 3 See p. 573. 4 loc* cit. (2). 5 As a fixing reagent Flemming’s weak solution was used. 576 Dale. — Observations on Gymnoascaceae. stained in various ways. The best results were obtained with Flemming’s triple-stain-safranin, gentian violet and orange G, and with toluidine blue and eosin. The latter stain is some- what uncertain, but when successful the results are very good. The eosin stains the nucleoli red, while the toluidine blue stains the protoplasm blue. A very useful stain for these Fungi is brazilin 1 , which dif- ferentiates the nuclei very clearly. Its special advantages are that its effects are very certain, and there is no over-staining. The results seem to be equally good, whether the material is stained before or after cutting. I. The Life-History of Gymnoascus Reessii. The original material consisted of little brick-red balls, made up of thick-walled septate hyphae, freely branching and anasto- mosing, and enclosing a mass of ripe ascospores, spherical in form and of a pale brown colour. These spores were for the most part isolated, but some were still contained in the spherical asci (PI. XXVII, Fig. 1). The thick-walled hyphae branch in a peculiar manner, the branches arising almost at right angles to the axis which bears them. Thus anastomosis is facilitated, and also the dense growth which results in the spherical mass of hyphae sur- rounding the groups of asci. The branches are said by Fischer 2 to be covered with ‘short, straight, or slightly bent spines, 10-15 j ul long.’ Both in the original material and in the cultures subsequently made from it, the ends of the hyphae were blunt (Fig. 1 a). The hyphae were either empty or contained a greater or less amount of protoplasm. None of the asci was attached to any hyphae. The ascospores readily germinated in various nutritive media. Those chiefly used were beer-wort, or horse-dung extract, made up with 10 per cent, or 15 per cent, of gelatine. Colonies were afterwards transferred either to sterilized horse- 1 Hickson, Q. J. M. S., vol. 44, p. 469 (1901). 2 Engler und Prantl, loc. eit., p. 294. Dale. — ■ Observations on Gymnoascaceae . 577 dung, or to beer-wort, or horse-dung extract, made up with 2 per cent, agar-agar, placed in test-tubes and sloped. In all these media the fungus grew well, and produced an abundance of ripe ascospores from which other cultures were made. The ascospore germinates by the bursting of the outer wall and the growing out of the germ-tube (Fig. 2 a-d). The germ-tube soon branches close to the spore and becomes * septate. Some of the branches grow almost parallel to the main axis in one direction, while adjacent ones grow in a com- pletely opposite direction (Fig. 2 d). In some cases the mycelium branches little, and grows straight on ; and in other cases the hyphae branch and curve considerably. In many mycelia, but not in all, the hyphal segments are swollen close to, and on one side of, each septum. This fact has been pointed out by Baranetzky, Brefeld, and others as characteristic of the family. Irregular knots of hyphae appeared in a hanging drop culture, but came to nothing. Apparently these were patho- logical, and due to the starved condition of the mycelium in the small drop. Similar irregular masses of hyphae have also been observed by Eidam 1 in Ctenomyces , a genus closely allied to Gymnoascus, and were by him also regarded as pathological. In cultures on horse-dung the mycelium had completed its first fructifications, and ripe ascospores were obtained, by the first week in July, that is, in about two months from the sowing of the spores. The vegetative mycelium varies greatly in external appear- ance according to the nature of the medium on which it is grown. If the fungus is growing on the surface of a dry medium, it forms a very small aerial mycelium, which is soft, flocculent, and perfectly white (Fig. 3). On it the fructifica- tions soon arise as little white bodies which become yellow and then brick-red. But if the medium is wet at the surface, or if the mycelium is sunk in it, e. g. in gelatine or agar, the aerial hyphae cling together in bundles and grow up in strands which stand erect and taper to a point (Figs. 4 1 loc. cit. (1), pp. 286, 287. 578 Dale . — Observations on Gymnoascaceae . and 6). After a while the hyphae at the ends of the strands separate from one another (Figs. 5, 7, and 8) and grow out into a flocculent mycelium like that grown on a drier medium. On this the fructifications arise. The plants grown under the latter conditions have a much longer period of vegetative growth and are much larger and stronger than the former. In fact the two types would not be taken for the same species they differ so greatly. So far as could be discovered none of the cultures of G. Reessii produced any conidia. The origin of the coils, which precede the formation of asci, takes place exactly as Baranetzky has described 1 and figured, and, although hundreds of sections were examined, no structures were seen like those described by Eidam 2 and by Brefeld 3 . In every case two branches arise from a single hypha, one on each side of a septum. These two branches grow upwards, at right angles to the hypha which bears them, and twist round one another once or twice. Their free ends swell up into club-shaped heads (Fig. 9), each of which now becomes cut off by a transverse wall as a separate cell (Fig. 10). The cells become very closely applied to one another, and soon the wall between them breaks down, and the two cells fuse. The fusion can be seen in specimens stained whole, but much more clearly in microtome sections (Figs. 11, 12, 26-29). At this stage there is usually no differentiation whatever between the two cells. But in some cases a differentiation may be noticed even before conjuga- tion. One cell, that called by Baranetzky the ‘ sterile cell/ is larger than the other, the ‘ ascogone ’ of Baranetzky. The sterile cell is almost straight, whereas the ascogone is longer, smaller in diameter, and is coiled round the sterile cell (Fig. 13). After conjugation the sterile cell grows larger and more spherical, so that the ascogone often comes to lie on its side, some distance from its apex (Fig. 14). The ascogone soon puts out a prolongation, which winds round the sterile cell (Figs. 13, 15, and 16). If the conjugating 1 loc. cit. 2 loc. cit. (1). 3 loc. cit. Dale . — Observations on Gymnoascaceae . 579 cells are of approximately the same size and shape, so that the apex of the ascogone and of the sterile cell are at the same level, the prolongation winds loosely and irregularly round the two cells (Fig. 1 5) ; but if the sterile cell is larger, so that the point of fusion lies some distance from its apex, the prolongation of the carpogone, at least at first, winds closely round the sterile cell (Fig. 14). After forming a considerable coil round the original con- jugating cells the prolongation of the ascogone becomes segmented, as may be seen in solid preparations (Figs. 17 and 19) and also in longitudinal and transverse sections (Figs. 18, 29 c). From most of these segments, not merely from one or two, short thick branches grow out, and soon themselves branch (Fig. 18) and form a dense mass of hyphae (Figs. 19 and 20). These are the ascogenous hyphae, and their ends swell up into the rounded asci. From below the sterile cell, and possibly from below the ascogone also, there eventually grow out a few vegetative hyphae which are longer, thinner, and straighter than the ascogenous hyphae (Fig. 21), but they do not arise till a considerably later stage in the development is reached. With regard to the behaviour of the nuclei the following facts have been observed. When the two hyphae forming the coil are still quite small each contains a single nucleus of considerable size, in which may usually be seen a nucleolus surrounded by a nuclear zone (Figs. 22 and 23). At the time of conjugation, however, both cells contain large members of nuclei , which, at least in certain stages, have each a distinct nucleolus and nuclear zone (Figs. 27 and 28). These nuclei must apparently have arisen by division from the original single nucleus, and .cases were noticed, which seem to be intermediate stages, in which there were several, but far fewer, nuclei (Figs. 24, 25, and 26). As the nuclei divide they become smaller in size, because the growth of the divided nuclei does not keep pace with division. When division is completed the nuclei grow until they attain their permanent size. The cells themselves are usually completely 580 Dale. — Observations on Gymnoascaceae. filled with dense protoplasm, but in some stages, apparently the later stages, the protoplasm is vacuolated. At the time of fusion a considerable portion of the wall between the two cells breaks down, and the nuclei and proto- plasm become mingled. Doubtless a nuclear fusion now takes place, but this has not been determined with certainty (Figs. 27 and 28). The nuclei pass over from the sterile cell into the ascogone (Fig. 28), and later into the prolongation of the ascogone (Fig. 16). Evidently they ultimately pass into the ascogonous hyphae, for, within a mass of ripening asci are to be seen ascogenous hyphae containing many nuclei, while the conjugating cells, though retaining their original shape and size, and often showing very distinctly the point of fusion, are completely empty (Fig. 29 a , b, and c). The numbers of nuclei in the ascogenous hyphae are so large that it would seem as if nuclear division occurred in these hyphae, more especially if we consider the enormous numbers of asci pro- duced from one pair of conjugating cells. The small asco- genous hyphae generally show one nucleus, with a nucleolus and nuclear zone, lying in the apex of the hypha, before it has begun to enlarge (Fig. 30 a). At a later stage when the apex is beginning to swell (Figs. 30 and 31) we find first two and then four nuclei which are smaller in size than the original nucleus, and apparently have no nuclear zone. In the stage with two nuclei, the nuclei in some cases lie one above the other (Fig. 30 b'\ and in other cases side by side (Fig. 30 b"), recalling the figures and descriptions given by Harper 1 and others of the development of the asci in the higher Ascomycetes. In Gymnoascus also the arrange- ment of the nuclei in two different planes may indicate that the nucleus has undergone two divisions. At a still later stage the ascus becomes larger and almost spherical, while, instead of being filled with dense protoplasm, it has a large central vacuole, so that the protoplasm and the eight nuclei it now contains, come to lie on the wall, 1 Sexual Reproduction in Pyronema confluens and the Morphology of the Asco- carp, Annals of Botany, Sept. 1900, vol. xiv, p. 363. Dale . — Observations on Gymnoascaceae. 581 usually, but not always, near the apex (Fig. 31 b). The nuclei now increase in size, and the protoplasm also seems to become more abundant, so that the vacuole disappears and the developing spores fill the ascus (Fig. 31 c ). At different stages in their development the young spores behave very differently towards stains. At first they are oval in shape and, with the toluidine blue method (cp. p. 576), their nuclei stain a deep pink with the eosin. In some young spores there are two deeply staining bodies (Fig. 33 a ) ; in others a single elongated body, which in some cases is thickened at each end (Fig. 32 b), and in other cases is thickened in the centre (Fig. 32 c). These observations suggest a nuclear fusion in the spores like that in the spores of Uredineae. At a later stage the spores become larger and rounder, and their contents stain more diffusely and not so deeply (Fig. 32 e). Finally the spores attain to their full size and become spherical. In this stage they remain colourless with the toluidine blue method (Fig. 32 f). With the triple stain, on the other hand, the ripe spores stain more deeply than those which are still immature. They become strongly coloured by the safranin. Amongst the ascogenous hyphae are a few thinner, slenderer hyphae, which often contain many small nuclei. These hyphae appear to be vegetative, and may either be those of the ordi- nary mycelium or those arising from the base of the coil. Some of the ordinary vegetative hyphae become changed into the thick-walled hyphae described above (p. 576, Fig. i), which envelop the asci. II. Gymnoascus setosus. The original material of this species also consisted of ripe ascospores and vegetative hyphae. The hyphae were so thick- walled, and coloured such a deep brown, that, except at their ends, they were opaque (Fig. 33). Their branching is pecu- liar, and both the main and the lateral branches end in sharp spines or bristles. They occurred in masses enclosing numbers of spindle-shaped colourless spores, either isolated or still R r 2 582 Dale. — Observations on Gymnoascaceae. within the spherical asci. The hyphae do not anastomose, although they branch considerably. The ascospores germinate by putting out one or two germ- tubes, which soon branch and form conidia by budding (Figs. 34-36). The end of a branch swells into an almost spherical knob, which is a conidium (Fig. 34). Immediately below it other conidia grow out. Branches, usually very short, and either spherical or oblong, arise, chiefly at the septa, but also at other points, and bud out at the top into conidia, which are formed in rapid succession (Figs. 34 and 35). These branches may be thrown off, and then frequently begin a yeast- like Budding. The conidial form of this species resembles those of some of the higher Ascomycetes, e. g. Nummularia , Xylaria polymorpha y & c., as figured by Brefeld 1 . The conidia germinate at once, but their behaviour varies under different conditions. If many conidia are sown in a small hanging drop they begin to bud at once, and the buds fall off as they do in a yeast (Fig. 37). In this connexion it may be noted that Klocker 2 states that yeast formation does not occur in the Gymnoascaceae, and draws conclusions therefrom in dis- cussing the affinities of the Gymnoascaceae. If a few conidia are sown in a drop a small mycelium is formed (Fig. 36). Similar differences occur in streak-cultures of conidia. If the spores be grown on 2 per cent, beer- wort agar scarcely any mycelium is formed, and the culture soon consists of nothing but a dense white powdery mass of budding conidia (Fig. 38). But sometimes, apparently if the agar has become drier and more concentrated, a mycelium is first formed (Fig. 39), which, however, soon becomes smothered in the enormous quantities of conidia which it produces. On such a mycelium the conidia-bearing branches somewhat re- semble a Verticillium , since they are produced, one or more together, chiefly at the ‘ nodes 5 of the hyphae, i. e. where the cross-walls occur (Fig. 35). Van Tieghem 3 has described a similar verticillate form in G „ ruber , but Eidam 4 doubts the 1 loc. cit. (2), PI. IX. 2 loc. cit. 3 loc. cit. (1), p. 160. i loc. cit. (e), p. 164. Dale. — Observations on Gymnoascaceae. 583 accuracy of this statement, and thinks that van Tieghem may have had a true Verticillium in his cultures. The conidial form is always pure white. This species has now (December, 1902) been kept in culture for a period of eighteen months, but so far it has never pro- duced any other kind of spore but conidia, although it has been grown under various conditions on different media. The cultures are still being continued in the hope of obtaining ascospores. As will be noticed below, other species are known which have only produced conidial forms in artificial cultures. III. Gymnoascus candidus. The original material again consisted of a mass of ripe asci and ascospores, and a few slender, colourless, almost un- branched hyphae, which had no connexion with the asci (Fig. 40). Hyphae, asci, and spores were all completely devoid of colour, and, to the naked eye, appeared as small, dense, and perfectly white masses. The ascospores germinate readily, and ripe fructifications are formed in a few weeks. On germination the minute ascospores swell considerably, and produce a mycelium of very thin and delicate hyphae. The young coils which precede the asci were first observed about three weeks after the sowing of the spores. Each coil consists of a central club-shaped hypha, the ‘ sterile cell J (to retain Baranetzky’s terminology), surrounded by a thinner hypha, the ‘ ascogone,’ which coils round it in a close, sym- metrical spiral (Fig. 41). The two hyphae may or may not arise from the same hypha ; more usually they appear not to do so. Nor do they arise simultaneously, as in G. Reessii ; for the ‘ sterile cell ’ is first formed, and the ‘ ascogone ’ afterwards grows round it, as far as the apex, and here, after each has been cut off by a transverse wall (Fig. 43), the two cells fuse with one another (Figs. 44, 45, and 46). The ascogone now segments (Figs. 46-48), and the greater number of the segments thus formed grow out into short thick hyphae (Figs. 46-48), which branch 584 Dale. — Observations on Gymnoascaceae. repeatedly and form round the coil a dense mass of asco- genous hyphae (Fig. 49). Besides the ascogenous hyphae a few vegetative hyphae seem to grow out from the base of the coil, as in G. Reessii (Fig. 50). The development of the asci and ascospores seems to take place exactly as in G. Reessii , except that the occurrence of a large vacuole is not so constant. But the exceeding minute- ness of the asci and their spores makes the details of their development very difficult to follow, even with the highest available magnification. For the same reason the behaviour of the nuclei is difficult to observe. There is no doubt, how- ever, that the conjugating cells about the time of fusion both contain numbers of small nuclei (Fig. 45), whereas in the youngest stage, as in G. Reessii , there seems to be but one large nucleus in each cell (Fig. 43 a). The young asci also appear at first each to have one large nucleus, with a nuclear zone, in the dilating end of the asco- genous hypha (Fig. 51 a). This evidently divides into two (Fig. 51 b), then into four, and finally into eight (Fig. 51 0 , which are small after division, but increase in size when the divisions are all completed. Certain slender hyphae, filled at the apex with small nuclei, are apparently vegetative hyphae like those occurring in G. Reessii (Fig. 51 e). As is the case in G. Reessii , the remains of the empty coil may be seen within the mass of ripening asci (Fig. 52). Besides ascospores this species also produces abundant oidia. Each colony produces either oidia or ascospores, or both. With the naked eye the ascogenous parts of the colonies are of a chalky whiteness and consistency, because the dense masses of minute asci cover up the small cushion of delicate hyphae which is first formed. In cultures grown from single asco- spores each colony forms a white circular mass, a centimetre or more in diameter, which usually produces asci at the centre and oidia round the periphery (Figs. 53 and 54). The hyphae form- ing the oidia are usually erect and branching, and form masses which, to the naked eye, are somewhat flocculent. As in G. Reessii and G. setosus the habit of the colonies Dale —Observations on Gymnoascaceae. 585 differs under different conditions. For example, oidia were sown in plates of beer-wort gelatine. The sowings were made from a pure culture, and yet two different kinds of colonies were formed — a dense kind and a loose kind. This difference was due simply to the fact that the dense colonies were sub- merged, while the loose form was growing on the surface of the medium. Microscopic examination of the oidium-bearing hyphae shows that they consist of erect hyphae branching dichoto- mously with great regularity (Figs. 55—57). When more highly magnified the protoplasm in these branches is seen to be collecting into regular squarish masses, each containing a large vacuole (Fig. 55 c). Finally, walls appear between the masses of protoplasm, and the walls break up into oidia (Fig. 56 a), which are at first flat at the ends, but which later become rounded (Fig. 57 ). Each oidium (Fig. 57 ) is larger than an ascus. The oidia readily germinate and form cultures indistinguishable from those grown from ascospores 1 . Amongst the vegetative hyphae of the oidium-bearing mycelium may often be seen thicker hyphae, which, however, bear branches of varying thickness (Fig. 58 ). Some of the thicker hyphae show the pyriform swellings (Fig. 59 ), the cyst-like ends to some hyphae, and the beaded appearance of other hyphae (Fig. 60), which are characteristic of the genus Gymnoascus and which have also been observed in other genera, e. g. in Onygena equina 2 . Besides the erect hyphae oidia may occur on the ascus- bearing mycelium, between the layer of sexual coils and the vegetative hyphae imbedded in the nutritive medium, but lying on the surface between the medium and the ascogenous layer. 1 The mycelium of another species of Gymnoascus , still under culture, behaves in a similar manner. 2 Marshall Ward, Onygena equina, Willd., a horn-destroying fungus, Phil. Trans., series B, 175, vol. cxci, pp. 269-291, PI. XXI, Figs. 11 and 12, PI. XXII, Fig. 13 (1899). 586 Dale. — Observations on Gymnoascaceae. The Various Kinds of Reproduction observed in the Gymnoascaceae. The occurrence of asexual spores has not been observed in all species of Gymnoascus. Some species, e. g. G. Reessii , seem to reproduce themselves exclusively by means of asco- spores. On the other hand, there are species which, at least under certain conditions, produce nothing but asexual spores. As examples may be noted the case of G. setosus just de- scribed, for, though Eidam 1 succeeded in obtaining the young coil, his cultures did not produce any ascospores. Another case is that of a species cultivated by Matruchot and Dassonville 2 , who do not, however, give its name. The majority of the Gymnoascaceae, however, produce in culture both sexual spores and also various kinds of asexual spores. Frequently these are of the type of chlamydospores, as, for example, in G. uncinatus 3 . In G. setosus (p. 582), and perhaps in G. ruber 3 , the conidia arise in a verticillate manner on erect subaerial hyphae. In G. setosus conidia may also arise by budding from a germinating conidium (p. 582). In G. candidus (pp. 584, 585) the asexual spores are oidia, resulting from the breaking up into spores of subaerial hyphae, which may either lie horizontally upon the substratum, or, more usually, stand erect and branch copiously. Conclusions. The investigations just described leave no doubt as to the occurrence of a sexual process in the Gymnoascaceae, if not in every species, at least in Gymnoascus Reessii and in G. candidus. Such a process has not before been described, though it was assumed by Baranetzky 4 , who, however, expressly states that 1 loc. cit. (2). 2 (1) Sur le Champignon de l’Herpes (Trichophyton) et les formes voisines, et sur la classification des Ascomycetes. Bull. Soc. Myc. de France, tom. xv, p. 250 (1899). 3 Eidam, loc. cit. (i), p. 298. 4 loc. cit., pp. 148 and 156. Dale— Observations on Gymnoascaceae. 587 he saw no fusion between the two cells, so that ‘ fertilization 5 must take place by means of £ transfusion * through the wall between them. Eidam 1 also takes a sexual process for granted in the species he cultivated, viz. G. Reessii , G. uncinatus , and in the closely allied genus Ctenomyces. On the other hand, van Tieghem 2 , Zukal 3 , and Brefeld 4 5 6 7 8 emphatically deny the occurrence of any sexual process what- soever. Van Tieghem, indeed, denies that sexuality occurs in any Ascomycete, on account of what he calls the ‘ monocarpous Ascomycetes,’ i. e. Ascomycetes in which, according to him, the asci arise from a solitary original branch 5 . The cases where actual fusion has been seen he regards as examples of purely vegetative union, comparable to ordinary anastomosis. Brefeld, according to whose observations the coils in G. Reessii are formed from a single branch, also, for this reason, considers that any idea of sexuality is quite out of the question. Some cases which he saw of coils made up of two hyphae, like those described by Baranetzky, he regards as pathological. But undoubted cases of fertilization in which has been seen the union, not only of the conjugating cells, but in some cases of their nuclei also, have now been recorded amongst the Ascomycetes, e. g. in Sphaerotheca Castagnei 6 and Pyronema conflnens 7 by Harper, and also in Eremascus albus* by Eidam, 1 loc. cit. (1), p. 300. 2 loc. cit. (1), p. 96. 3 Ueber einige neue Pilzformen und iiber das Verhaltniss der Gymnoascen zu den iibrigen Ascomyceten : Berichte der Deutschen Bot. Gesellschaft, Bd. viii, p. 295 (1890). (2) Sur le d^veloppement du fruit des Chaetomium et la pretendue sexuality des Ascomycetes. Ann. des Sci. Nat., 6 e ser., vol. ii, p. 364 (1875). 1 loc. cit. (1), p. 159. 5 (3) Sur le d^veloppement du fruit des Ascodesmis , genre nouveau de l’ordre des Ascomycetes. Bull, de la Soc. Bot. de France, vol. xxiii, p. 271 (1876). 6 Die Entwickelung des Peritheciums bei Sphaerotheca Castagnei'. Ber. der Deut. Bot. Ges., Bd. xiii, p. 475 (1895). 7 Sexual reproduction in Pyronema confiuens , and the morphology of the Ascocarp. Annals of Botany, vol. xiv, p. 321 (1900). 8 (3) Zur Kenntniss der Entwickelung bei den Ascomyceten. Cohn’s Beitrage, vol. iii, p. 385 (1883). 588 Dale.— Observations on Gymnoascaceae . and in Monascus by Barker l , though not in those forms which are most nearly related to Gymnoascus . The affinities of the Gymnoascaceae have gradually become apparent, as our knowledge of the family has increased by the addition of new genera and species. The investigations which have been recorded above seem to throw some further light on this interesting question. One of the forms most nearly allied to Gymnoascus is Cteno- niyces serratus. Ctenomyces serratus was first described by Eidam 2 , and bears a most striking resemblance to Gymnoascus candidus ; in fact, the description given by Eidam of the de- velopment of the coil and of the ascogenous hyphae and asci in Ctenomyces would serve equally well for G. Candidas. Eidam, however, did not see any cell-fusion, or any nuclei in Cteno- myces. The only difference between Ctenomyces and G. Candidas is that whereas the former (like most other species of Gymnoascus hitherto described) has hard, thick-walled hyphae round the asci, the mycelium of Gymnoascus Candidas consists exclusively of extremely thin and delicate hyphae. The resemblance between the two species extends to the asexual spores, but in Ctenomyces these are conidia, budded off laterally from the hyphae, while in G. Candidas they are oidia. Another closely allied species is Eidamella spinosa, a parasite growing on the skin of a dog. Matruchot and Dassonville 3 , who founded the genus, made pure cultures which produced asci. The original coil arises exactly as in Ctenomyces and in Gymnoascus Candidas from two branches, which sometimes grow out from one hypha, sometimes from two. But occasionally an anomalous case occurs, in which a single branch coils round the hypha from which it sprang. It is interesting to note that this is what Eidam observed in G. Reessii , and what he also records as an occasional occurrence in Ctenomyces. Eidamella also produces chlamydospores. This species is particularly 1 Morphology and Development of the Ascocarp in Monascus. Ann. of Bot., Jan. 1903. 2 loc. cit. (1), p. 271. 3 (2) Eidamella spinosa , Dermatophyte produisant des peritheces. Bull, de la Soc. Myc. de France, tom. xvii, p. 123 (1901). Dale . — Observations on Gymnoascaceae . 589 interesting, as the authors point out, because it is the first der- matophyte which has produced asci under artificial culture. The life-history of Gymnoascus Reessii shows affinities in other directions, some of which have already been pointed out by previous investigators. Attention has been drawn to the fact that, though the young coils in this species always consist of two cells which are at first identical, certain variations may occur later which seem to indicate affinities with other genera and species. For example, when the two cells are of the same size and shape at the time of conjugation, they exactly resemble the similar stage which Eidam has described and figured in Eremascns albus 1 2 (cp. Figs. 9-1 1 with Eidam’s figures on his PI. XIX). Eremascns was originally placed by Eidam amongst the Gymnoascaceae, and was by him regarded as forming a link between the Mucorineae and the Ascomycetes. In connexion with the possibility of a connexion between the Gymnoascaceae and Zygomycetaceae it is interesting to remember that the sexual reproductive organs described and figured by Eidam in Basidiobolns ranarum 2 originate exactly in the same way as in Gymnoascus Reessii , namely, by the out- growth of two adjacent cells, close to the septum which divides them from one another, and that these two cells fuse together as in Eremascns and Gymnoascus . Schroter, in Engler and Prantl 3 , however, places Eremascns amongst the Endomycetaceae, which, together with the Sac- charomycetaceae, form the group of the Protoascineae. If, on the other hand, the sterile cell in Gymnoascus Reessii grows more rapidly than the ascogone, the latter grows round the former in a manner suggesting G. candidus , Ctenomyces , and Eidamella. Such a variation which, as it were, unites the type of G. Reessii and that of G. candidus also very closely agrees with the descrip- 1 loc. cit. (3). 2 (4) Basidiobolns : eine neue Gattung der Entomophthoraceen. Cohn’s Beitrage, Band iv, Heft ii, p. 181 and Taf. xi (1887). 3 loc. cit., p. 132. 590 Dale. — Observations on Gymnoascaceae. tion and figures drawn by Eidam of the early stages in Asper- gillus ( Sterigmatocytis ) nidulans \ The fate of the two hyphae was not determined with certainty, but asci were ultimately formed from the coil. Another species of Aspergillus, e. g. A.herbariorum (Wiggers), of which figures are reproduced by Engler and Prantl 1 2 , does not resemble the Gymnoascaceae nearly so closely as A . nidulans. In view of recent work on the sexuality of the lower Asco- mycetes it would seem worth while reinvestigating, by means of modern histological methods, the life-histories of Aspergillus and Penicillium. The obvious resemblances between the early stages of the coil of Penicillium and that of Gymnoascus Reessii have been noticed by previous investigators, and have led to the families of the Aspergillaceae and the Gymnoascaceae being included, with others, amongst which may be mentioned the Onygena- ceae, in the group of the Plectascineae 3 . Previous to their discovery of Eidamella, Matruchot and Dassonville had drawn attention to the possibility of a relation- ship between the Gymnoascaceae and certain dermatophytes 4 , especially Trichophyton 5 , on account of the similarity in the asexual reproduction. The life-history of Eidamella confirmed their view, which now seems also to be strengthened by the likeness between Gymnoascus Candidas and Eidamella. These authors place the Gymnoascaceae between the Endomyceta- ceae, on the one hand, and the Onygenaceae on the other, and give the following classification 5 : — 1. Endomycetees. Endomyces. 2. Gymnoascees. Gymnoascus , Ctenomyces, Trichophyton, A chorion (?), Microsporum (?), &c. 3 . Onygenees. Onygena. 1 loc. cit. (3), p. 406 et seq., PL XXI, Figs. 8-14. 3 loc. cit., p. 301, Fig. 214. 3 Engler und Prantl, loc. cit., p. 293. 4 loc. cit. (1), p. 240. (3) Sur le Ctenomyces serratus, Eidam, compare aux champignons des Teignes. Bull. Soc. Myc. de France, tom. xv, p. 305 (1899). (4) Sur une forme de reproduction d’ordre eleve chez les Trichophyton. Bull. Soc. Myc. de France, tom. xvi, p. 201 (1900). 5 (1) p. 251. Dale. — Observations on Gymnoascaceae. 591 Later they place Eidamella amongst the Gymnoasceae 1 i near to Myxotrichum. With regard to Endomyces decipiens , no sexual organs have been found, but the life-history of G. candidus tends to confirm the views of Matruchot and Dassonville. In neither G. candidus nor Endomyces decipiens are there any thickened hyphae, but in both the asci are completely naked and borne on delicate colourless hyphae. In both the mycelium breaks up into oidia 2 . The life-history of Endomyces would probably repay reinvestigation, with a view to ascertaining the presence or absence of sexual organs before the production of asci. The chief difference between these two species is that in Endomyces decipiens each ascus contains only four ascospores, whereas in Gymnoascus candidus there are eight spores in each ascus. Van Tieghem 3 also compares Gymnoascus with Hypomyces (Endomyces) on the one hand, and on the other with Peni- cillium. Boudier 4 , as well as Matruchot and Dassonville, regards the Gymnoascaceae as having close affinities with Onygena. Indeed, he considers that the Gymnoascaceae do not differ essentially from the sessile species of Onygena. Matruchot and Dassonville claim that Marshall Ward’s recent work on Onygena 5 confirms their views as to the relation between the Gymnoascaceae and the Onygenaceae. Though no definite coil was seen by this author, the resemblances between the two families are very strong. In both the ascus formation is preceded by a coil, and the asci and ascospores develop in the same way. In both families there are chlamydo- spores ; in both pyriform swellings and cyst-like swellings at the ends of the hyphae occur in the vegetative mycelium. But since definite sexual organs are unknown in Onygena , its exact systematic position is uncertain. 1 loc. cit. (1), p. 128. 2 loc. cit., p. 155, Fig. 135. 3 loc. cit. (1), p. 161. 4 Description de deux nouvelles especes de Gymnoascus de France. Bull. Soc. Myc., tom. viii, p. 43 (1892). 5 loc. cit. 592 Dale . — Observations on Gymnoascaceae . A comparison of the habitats of the various genera included in the Gymnoascaceae and Onygenaceae is also very suggestive in considering their affinities. For example, many species of Gymnoascus live either on the excrements of animals or on various parts of dead or living animals. G. ossicola and G. aurantiaca have been found growing on old bones. Eidam found G. Reessii growing on the dead pupa of Sphinx Gallii. G. umbrinus has been found on a dead cockchafer, G. candidns on the feathers of owls, G. setosus on an old bee’s nest and on an old wasp’s nest, which probably both contained excrements ; G. reticnlatus was found on the decaying horn of a cow, and G. myriosporus on the surface of the claws of birds of prey, and also on the excrements of these birds ; Ctenomyces grows on feathers, Onygena on horn ; Eidamella was obtained from the skin of a live dog, and is, according to Matruchot and Dassonville, related to other dermatophytes, e. g. Trichophytoii. Moreover, the genera and species included in the Endomy- cetaceae, the Gymnoascaceae, and the Onygenaceae fall into a series in which there is a gradually increasing complexity in the structure of the fructification. In Endomyces decipiens the asci are naked and solitary, and are produced on the ends of branching hyphae and show a tendency towards aggregation. In Gymnoascus candidus the asci, while still completely without investment, are aggregated together in dense masses, each mass being produced from a single pair of conjugating cells. In other species of Gymnoascus , in Ctenomyces , and in Eidamella the groups of asci are more or less enclosed in a loose investment of thick-walled, branching, and, in most cases, anastomosing hyphae. In Aspergillus and Penicillium the still more compact groups of asci are each surrounded by thick-walled hyphae, which form a continuous wall of pseudo-parenchyma — the peridium. In Onygena also the asci are enclosed in a complete invest- ment, which in some respects is more differentiated than that of the Aspergillaceae. In comparing the sexual organs of the forms under con- Dale. — Observations on Gymnoascaceae . 593 sideration Endomyces and Onygena must be omitted, because in them such organs are unknown. But in all the other species the asci are the product of ascogenous hyphae arising from two cells which in every case are in close contact with one another, and which in two species, Gymnoascus candidns and Gymnoascns Reessii have been seen to actually fuse. Thus the probability of a sexual process in the allied genera is increased. Evidently, then, the normal origin of the reproductive organs in this series is by means of two cells arising as branches, either from the same hypha or from two adjacent hyphae. But anomalous cases occur, like those described by Eidam in G. Reessii (p. 572) and in Ctenomyces (p. 588), in which a single branch coils round the parent hypha. Still more abnormal cases, which are undoubtedly pathological, are the irregular coils like those seen by Eidam in Ctenomyces and by the present writer in a starved drop culture of G. Reessii (p. 577 ). Such coils never produce asci, but soon degenerate. It seems, therefore, as if this series of forms was natural, and based, not upon mere resemblances, but upon real affinities. 594 Dale . — Observations on Gymnoascaceae. DESCRIPTION OF FIGURES IN PLATES XXVII AND XXVIII. Illustrating Miss Dale’s paper on the Gymnoascaceae. Figs. 1-32. Gymnoascus Reessii. Fig. 1 a . Part of the original material, consisting of hard thick-walled hyphae and loose ascospores. (2.F.) Fig. 1 b. The spores more highly magnified. (4*F.) Fig. 2 a-d. Germinating ascospore. Fig. 3. Photograph of young colonies growing on a dry substratum in a culture plate. Fig. 4. Photograph of similar colonies on a wet substratum. Fig. 5. Photograph of older colonies in which the upper part of the mycelium grown on a wet substratum is becoming flocculent. Fig. 6. Drawing of a mycelium on a wet substratum. Fig. 7. An older stage of the same, in which the aerial hyphae are separating from one another. Fig. 8. Still older stage of the same. Fig. 9. Early stage in the formation of the sexual organs. Fig. 10. The sexual organs more twisted round one another. Figs. 11 and 12. Surface views of conjugating sexual cells. In 11 the two cells are of the same shape and size, in 1 2 one is larger ; but both are coiled. Fig. 13. A similar stage where one cell is much straighter than the other. Fig. 14. A later stage of a form like that in Fig. 13. a, the outgrowth of the * ascogone.’ Fig. 15. Two coiled cells after conjugation, showing the outgrowth a. Fig. 16. Section of a similar stage, showing nuclei. Fig. 17. Section of the segmented outgrowth round the end of the ‘ sterile cell.’ Fig. 18. The segments of the outgrowth forming branches which are the ascogenous hyphae. Fig. 19. Surface view of segmented and branching outgrowth, a , vegetative hyphae. Fig. 20. Group of ascogenous hyphae produced from a pair of sexual cells. Fig. 21. Section showing vegetative hyphae springing from the base of the sexual organs. Fig. 22. Section of young sexual cells, each containing a single nucleus. Fig. 23. Later stage, after nuclear division and the formation of a dividing wall below the ‘ sterile cell.’ The nuclei have increased in size, and show a distinct nucleolus and nuclear zone. Fig. 24. A later stage in which the nuclei have undergone division. Fig. 25. A still later stage in which the nuclei are more numerous and smaller. Fig. 26 a , b , c. Conjugating sexual cells in transverse section. Fig. 27. The same in longitudinal section, showing many small nuclei. DALE. GYMNOASCACEAE. Voi. xvil, pi.xmi University Press, Oxford. m. xvii. pi.xmi §%<- f University Press, Oxford. DALE. GYMNOASCACEAE. # f ■■ 5 . Annals of Botounij DALE. GYMNOASCACEAE. Voi.xvii, pi.xmii. %C# I University Press, Oxford m. xvii pi. mm tXInnals of Botoony University Press, Oxford DALE. GYMNOASCACEAE. Dale . — Observations on Gymnoascaceae . 595 Fig. 28. Conjugating cells, showing the passage of nuclei from the ‘sterile cell ’ into the * ascogone.’ Fig. 29 a, b, c. ‘Sections of the old sexual cells as they occur in the centre of the ascocarps after their contents have passed into the ascogenous hyphae. 29 a shows ascogenous hyphae, vegetative hyphae, and developing asci. 29 c shows the segmented outgrowth of the ascogone with some of its branches. Fig. 30 a-d. Development of asci. a. Young ascus with a single large nucleus. b. Older ascus with the nucleus divided into two. The nuclei sometimes lie in one plane, b ', sometimes in another, b". c . Stage with four nuclei, d. Stage with eight or more nuclei. Fig. 31 a-d. Development of ascospores. a. Stage with four nuclei and a large vacuole, b. Stage with eight nuclei and a large vacuole, c. The eight nuclei enlarged in size, and surrounded by so much protoplasm that the vacuole has almost disappeared, d. The young spores surrounded by their walls. Fig. 32 a-f. Ascospores. a. Ascospore with two deeply staining bodies, b , the two bodies united by a stained protoplasmic strand, c. Spore with a densely stained central body with stained protoplasmic strands at each end of it. d. Spore with deeply stained central body. e. Larger spores diffusely stained, f Mature spores. Figs. 33-39. Gymnoascus setosus. Fig* 33 a. Part of the original material showing thickened spiny hyphae and loose ascospores (2.D). 33 b. Part of the same more highly magnified. (4.F.) Fig. 34. Formation of conidia. (4.F.) Fig- 35 - Conidial branches. (4-F.) Fig. 36. Conidium producing a small mycelium bearing other conidia. Fig- 37 - Conidia budding. (4-F.) Fig- 38. Streak culture consisting almost exclusively of masses of conidia. Fig- 39. Streak culture consisting of a mycelium bearing conidia. Figs. 40-60. Gymnoascus candidus. Fig. 40. Part of the original material showing conidia and vegetative hyphae. Fig. 41 a-c. Young stages of the young coil, consisting of a thick straight cell surrounded by a thin coiled hypha. Longitudinal sections or surface view. Fig. 42. The same in transverse section. Fig. 43 a and b. Longitudinal section of an older stage showing the central cell cut off by a transverse wall. Fig. 44. Conjugating cells in longitudinal section, a. Vegetative hyphae. Fig. 45. Conjugating cells in transverse section. Fig. 46 a. Central cell surrounded by the ascogone divided into segments. Fig. 46 £. Conjugating cells with the ascogone segmented and branching. Fig. 47 0, b. Transverse section of central cell surrounded by segmented and branching ascogone. Fig. 48 a. Longitudinal section of central cell surrounded by the segmented and branching ascogone. Fig. 48 b. The same in surface view. Fig. 49. Group of young asci developed from a pair of conjugating cells. Fig. 50. Young sexual coil showing origin of vegetative hyphae. Fig. 51 a-e. Development of asci. S S 596 Dale —Observations on Gymnoascaceae . Fig. 52. Group of developing asci. Fig. 53- Photograph of a streak culture on beer-wort agar. Fig. .54. Sketch of a colony bearing asexual spores round the sircumference, and ascospores in the centre. Fig. 55. A branch in which the protoplasm is dividing into masses. Fig- 55 a ‘ Part °f a mycelium about to break up into oidia. 55 b. Part of the same more highly magnified. Fig. 56. A branch breaking up into oidia. Fig. 57. Mature oidia. Figs. 58, 59, 60. Parts of the old vegetative mycelium. (Figs. 9-32 and 41-52 were drawn with the camera lucida, the lenses used being Zeiss 1.5 oil immersion objective and no. 4 eye-piece.) Proteolytic Enzymes in Plants (II). BY S. H. VINES, Sherardian Professor of Botany in the University of Oxford. I N the January number of the present volume ( 1 ) I pub- lished some observations tending to show that proteolytic enzymes are of very general occurrence in plants. Whilst it had previously been implicitly assumed by physiologists that this was probably the case, the first experimental demonstration of the fact was, I believed, that contained in my paper. It turns out, however, that I was mistaken. My attention has since been directed to a paper by Buscalioni and Fermi ( 2 ), published in 1898, which somewhat anticipates my results: but though our conclusions are concordant on the whole, our methods were widely different. The method of Buscalioni and Fermi is an adaptation of the gelatine- culture of Bacteria. A layer of gelatine, with carbolic acid (•5-1 °/ o ) as the antiseptic, covers the floor of a Petri-dish, and upon this are placed the objects (seeds, portions of leaves, &c.) whose proteolytic action is to be determined ; the test being, of course, the liquefaction of the gelatine. By this simple method the authors were able to detect more or less marked proteolytic activity in many Fungi, but by no means in all those tried ; in some Algae ( Codium tomen - tosum , P-adina Pavonia, Char a sp., Dictyota dichotoma , Cera- mium sp.) ; and in some Lichens : but the experiments with a Moss ( Funaria hygrometricc :), a Liverwort ( Lunularia vul- [Annals of Botany, Vol. XVII. No. LXVII. June, 1903.] S S 2 598 Vines. —Proteolytic Enzymes in Plants (II). gar is), with Equisetum sp. (rhizome), and with the leaves and rhizomes of various Ferns, all gave negative results. Turning to the Phanerogams, the authors give first their results with laticiferous and resinous plants, and these are rather conflicting. They found no digestive action in the liquids of the various Fumariaceae ( Corydalis luted), Papaver- aceae ( Papaver somniferum, P. Rhoeas , Argemone mexicana ), and Compositae ( Crepis setosa , Sonchus tenerrimus , Taraxa- cum officinale, Lactuca sativa) that they investigated. On the other hand, positive results were obtained with all the Urticales tested, viz. Ficus Carica and F. elastica, Morus alba and tatarica , Broussonetia papyrifera, and Maclura aurantiaca. In the remaining orders, some species were, whilst others were not, found capable of liquefying the gelatine ; for instance, in the Euphorbiaceae, Euphorbia Lathyris, E. Tirucalli, E. canariensis, E . balsamifera, E. coerulescens , E. grandidens , and Poinsettia pulcherrima were active, whilst Euphorbia tigridis and dulcis, Homalanthus populifolius, and species of Croton were not : similarly in the Convolvulaceae, Cotivolvulus sylvaticus and Calonyction (Tpomoea) macrantholeucum were active, but not Convolvulus arvensis and species of Ipomoea : in the Asclepiadaceae, Tweedia neerifolia and Asclepias curas- savica were found to be active, but not Hoya carnosa : in the Apocynaceae, Tanghinia venenifera and Plumeria alba were active, but not Vinca minor, Acokanthera spectabilis, nor Echites flavescens. It is interesting to note that the resin of Pinus halepensis showed some activity, if only weak, as did also the secretion of Nelumbium speciosum. Of juices expressed from the plant, but few were active, namely those obtained from the young leaves of Agave mexicana and A. americana, from the young stems of Phyto- lacca dioica, from the stems of Anagallis arvensis, from the apices of the shoots of Glycine sinensis. Amongst the con- siderable number of inactive juices were those obtained from old leaves of Agave mexicana , and from adult branches of Phytolacca dioica ; hence it would appear that young tissues are more likely than old ones to contain the protease. Vines.— Proteolytic Enzymes in Plants (II). 599 The action of sections of stems and leaves was next investi- gated : and here again the number of positive results is much smaller than that of negative. Out of a list including about fifty species, only a few were markedly active ; namely, sections of the leaf of Dyckia princeps , of young shoots of Phytolacca dioica , of P. abyssinica , and of Portulaca oleracea . In the case of Phytolacca abyssinica , it is specially noted that sections of young tissues acted much more powerfully than those of older parts. In the case of roots, those which proved to be active were about equal in number (38) to those that failed to act, though in many cases the activity was slight. The most active roots were those of A morphophallus Rivieri , of Aspidistra elatior , and of an undetermined Bromeliad. The authors contrast the more general distribution of the enzyme in the roots with its more restricted distribution in the green parts, where its presence seems to be especially associated with rapid growth. At the same time they find reason for doubting if the penetration of the tissues of the parent member by endogenously developing roots is due in any degree to the action of the proteolytic enzyme ; in fact they assert that the ‘ poche digestive ’ of van Tieghem has no significance so far as the solution of proteids is concerned. In this connexion they mention that their researches were carried on in the month of July, when conditions were most favourable for ferment action. The number of bulbs, tubers, and tuberous roots examined was but small, only twelve, and the positive and negative results were equally divided. The tubers of Tamils communis and of Dioscorea bulbifcra, , as also the tubercular roots (con- taining Anabaena) of Cycas revoluta were found to be most active, whilst the root-tubercles of the Leguminosae acted but feebly. The bulbs examined were those of Allium sativum , Cepa , and Porrum , but they were not found to be active ; nor were the tuberous roots of Beta and of Dahlia , From these facts the conclusion, which seems to me to be hardly justified by the facts, is drawn that of these organs those that are 600 Vines. — Proteolytic Enzymes in Plants (//). modified roots are more generally active than those that are modified shoots : for of the three cases in which vigorous liquefaction was observed, one only ( Cycas ) is a true root, whilst the organs of the other two are of cauline origin ; this is certainly true of the tuber of Tamus communis , and I believe it is also true of Dioscorea bulbifera. Next come the experiments with flowers and fruits, of which about sixty are recorded. Of the various parts of the flower, the stamens and the pollen proved to be by far the most active. Only three experiments were made with pollen ( Hedychium maximum , Hibiscus speciosus, Cucurbita maxima ), and in all three liquefaction was marked. A considerable number of fruits was tested, among others the Grape, the Orange (epicarp), the Lemon (unripe), the Red Currant, the Peach, the Apricot, the Cherry, and the Strawberry, but with invariably negative result. These are followed by the experiments with seeds. A few unripe seeds were investigated, and of these only a small number gave positive results, one of them being Phaseolus multiflorus . Among a number (22) of ripe seeds, those of Sorghum cernuum , Cannabis sativa , Linum usitatissimum (especially the seed-coat), and Anagallis arvensis , were found to be active. Contrary to what might have been anticipated, the authors found that many germinating seeds, whether albuminous or exalbuminous, were quite inactive. Some observations were also made on parasitic Phanero- gams. The presence of a protease was indicated only in the haustoria of Orobanche Hederae and of Cuscuta , the other parts of these plants apparently containing none of it : nor was any trace of it detected in Viscum album or in Loranthus europaeus. Finally, attention was directed to ‘insectivorous plants.’ The results obtained with Drosera were sometimes positive, sometimes negative. The investigation of Nepenthes was effected by placing pieces of the pitcher upon the gelatine, some having the inner and some the outer surface in contact with it : in the former case the gelatine was liquefied, but not Vines. — Proteolytic Enzymes in Plants (I/). 601 in the latter. The liquefying action of both Utricularia and Aldrovanda was but slight, as was also that of Sarracenia purpurea. The memoir concludes with some general considerations as to the action of heat and light upon the enzyme, and as to the influence of the reaction of the medium upon its activity. With regard to the latter point, the general con- clusion arrived at is that in the large majority of cases the presence of acid increases the activity of the enzyme, the presence of alkali diminishes it. The acids employed were chiefly organic, the citric, tartaric, and oxalic, in i °/ o solu- tions: in a few instances i °/ o HC1 was used, and was found to promote liquefaction by Ficus, and Phytolacca abyssinica , but more frequently its effect was unfavourable. In only one case, that of Tuber aestivum , was liquefaction limited to an alkaline medium (3% Na 2 C 0 3 ). In certain others, however, such as the style and stigma of Hibiscus speciosus , the latex of Ficus Carica , and the unripe seeds of Phaseolus multijlorus , experiments of 24 hours’ duration in the alkaline medium showed vigorous liquefaction. It is . not impossible that these results may have been due to Bacteria ; the authors themselves do not seem to attach importance to them. I have thought it necessary to give this rather full account of the researches of Buscalioni and Fermi, because their work is not, I believe, as well known as it deserves to be, at least among English botanists ; and also because a certain amount of detail is necessary for the discussion of the relation of their results to those that I have obtained by an altogether different method. I am glad to find that our conclusions are in agree- ment so far as general principles are concerned. The demon- stration of the wide distribution of a proteolytic enzyme in the plant-body, is the outcome of their experiments as of my own. There is, not unnaturally, some divergence in matters of detail. For instance, they found such laticiferous Composites as the Lettuce and the Dandelion to be inactive, whereas I -found them to be active, and I have since found the leaves of the Endive to be active. The same divergence 602 Vines . — Proteolytic Enzymes in Plants {II). exists with regard to the Beet-root, and to the epicarp of the Orange. These divergences probably depend to some extent upon seasonal differences in the material examined, upon the higher temperature which I employed, and perhaps to an even greater extent upon the antiseptics used in the different experiments. Buscalioni and Fermi used exclusively carbolic acid ; whereas I have never done so, but have used chiefly hydrocyanic acid or chloroform-water. In subsequent pages of this paper, I propose to consider the relation of various antiseptics to proteid-digestion in some detail. Further, we are in agreement in the general conclusion that the vegetable proteases are most active in an acid medium. But as regards the products formed in digestion we neces- sarily part company : for it was not possible by the gelatine- method to obtain the information afforded by the tryptophane- method. Buscalioni and Fermi mention, indeed, that in certain cases they obtained the biuret-reaction, indicating the presence of albumoses or peptones, in the liquefied gelatine, but they did not attempt to pursue the subject further. The advantage of the tryptophane-method adopted by me, is that it throws light upon this fundamental question, and that any kind of proteid matter can be subjected to experiment. Whilst the gelatine-experiments of Buscalioni and Fermi were the first to indicate the wide distribution of proteases in plants, my tryptophane-experiments demonstrated that these widely- diffused substances are completely proteolytic in action, so far as they have been investigated. Proteases and Antiseptics. I have already suggested that such divergences as exist between the observations of Buscalioni and Fermi and my own are probably due, at any rate to some extent, to the fact that we respectively made use of different antiseptics. This suggestion is based on results that I have obtained tending to show that the same protease is affected differently by different antiseptics, as also that different proteases are diversely affected by the same antiseptic. In the following paragraphs Vines. — Proteolytic Enzymes in Plants (II). 603 I give an account of my experiments in this direction, so far as they have gone. In March, 1902, I published in this periodical a paper (3) which dealt, among other topics, with the digestive properties of papain. I there adduced evidence to prove that this protease proteolyses fibrin and Witte-peptone, and is more active in acid than in neutral or alkaline liquids, as indicated by the tryptophane-reaction. As regards its proteolytic action, my results confirmed those of Martin (4), who had found leucin and tyrosin among the products of digestion. After my MS. had left my hands, I received a paper on the subject by Mendel and Underhill (5), which contains observa- tions apparently disproving the proteolytic activity of papain, and suggesting that it can only peptonize the higher proteids. This was followed, after an interval of several months, by a second paper (6), w r hich, without adducing fresh experi- mental evidence, restates the conclusions of the previous paper, criticizing also the view, to which I have more than once given expression, that all known vegetable proteases decompose the proteid molecule into leucin, tyrosin, trypto- phane, & c., that is, are completely proteolytic. The facts upon which Mendel and Underhill rely, are that in over sixty trials made with four different samples of papain, and with casein, fibrin, coagulated egg-albumin, and boiled muscle-tissue as the material to be digested, they failed to detect leucin, tyrosin, or tryptophane. Only with fresh, unboiled muscle were these products obtained, a result that these authors attribute to the self-digestion (autolysis) of the tissue. In all the experiments, sodium fluoride (NaF i # /J was the antiseptic employed. On this evidence they con- clude that papain is an enzyme differing from both pepsin and trypsin. ‘ While the products of the papain digestion of proteids resemble quite closely those of pepsin, . . . the enzyme differs from animal pepsin in that it acts readily in both neutral and alkaline media. On the other hand, although papain is comparable with trypsin in exerting a solvent action in fluids of various reactions, the failure to form leucin, tyrosin, 604 Vines. — Proteolytic Enzymes in Plants (II). or tryptophane in appreciable quantities — at least under con- ditions in which they are readily formed in large quantities by the other tryptic enzymes — places it in a class of its own for the present/ In endeavouring to account for the wide divergence between their conclusions and my own, I was at first inclined to question the activity of the papal'n employed by Mendel and Underhill ; but the numerical results which they give show conclusively that a considerable amount of the proteid supplied (as much sometimes as 7o°/ o ) was dissolved, and the peptonization of casein was definitely proved. Hence there is evidence that the papal'n was active. This being so, the only remaining difference in the material of the two sets of experiments lay in the antiseptics employed, sodium fluoride in theirs, hydrocyanic acid in mine. I had already drawn attention to the fact that papain-digestion is promoted by HCN, and I thought it not improbable that this might prove to be an important factor in the problem. I accordingly instituted the following comparative experiments, in which NaF and HCN were the respective antiseptics, with results that fully realized my anticipation. In the first instance I made use of Witte-peptone as the digestible material, and sodium fluoride (NaF), hydrocyanic acid (HCN), and chloroform-water as the antiseptics, the; solutions being neutral, acid, or alkaline. The result proved that the proteolysis, as indicated by the tryptophane-reaction, was much more marked in the acid liquid containing HCN than in any of the others : it was less marked in the chloro- form-water liquids, and scarcely perceptible in those contain- ing NaF. The details of the experiment were as follows : 5 grms. of papain ('purified papain/ Christy) were extracted for 3 hours with 250 cc. distilled water ; the liquid was then filtered : the filtrate was a clear brownish liquid, distinctly acid, giving good biuret-reaction but no tryptophane-reaction. 10 grms. of Witte-peptone were similarly extracted with 250 cc. dist. water: on filtration a yellowish, neutral solution was obtained giving no tryptophane-reaction. Vines . — Proteolytic Enzymes in Plants (//). 605 25 cc. of each of these solutions were then placed in each of 10 stoppered bottles : the contents of 3 of these were acidified by the addition to each of *25 grm. of citric acid (—0*5 %), the contents of other 3 made alkaline by the addition to each of 0*12 grm. of Na 2 Co 3 (= -25%), whilst to the remaining 3 neither acid nor alkali was added : the contents of the last 3 were slightly acid, but they are distinguished below as ‘ neutral/ To an acid, an alkaline, and a neutral bottle, 0-5 grm. of NaF was added (= 1 %) : to a similar set, HCN was added to 0-2 % : to a third set of 3, chloroform was added to 0-5 %. A control bottle contained 25 cc. of boiled papai'n-solution, with 25 cc. of Witte-peptone solution. After 18 hours’ digestion at 4o°C., the tryptophane-reactions were as follows : — HCN. Chlorof. NaF. Acid very strong marked distinct Alkaline distinct faint faint Neutral distinct faint faint. The control bottle gave a scarcely perceptible reaction. These results indicate to how great an extent the activity of papain is affected by the antiseptic employed ; and more especially that sodium fluoride exerts a strong inhibitory influence. Moreover, the advantage of an acid over an alkaline or a neutral medium is apparent. In order to more definitely establish these conclusions, the experiment was repeated with fibrin instead of Witte-peptone : each bottle contained 1 grm. of fibrin, otherwise the contents were the same as in the preceding experiment, except that the percentage of Na 2 C 0 3 in the alkaline bottles was increased to 0-5 °/ o . After eighteen hours’ digestion, at 40° C. 3 the results were : — - NaF. distinctly attacked faint trypt. scarcely attacked doubtful trypt. mostly disintegrated faint trypt. Acid HCN. J fibrin quite disintegrated (marked tryptophane ( fibrin quite disintegrated JrL LK>CLLZfl& \ r • . . . 1 (faint tryptophane ( fibrin nearly all gone Neutral (distinct tryptophane Chlorof. scarcely attacked faint trypt. scarcely attacked doubtful trypt. distinctly attacked faint trypt. 606 Vines . — -Proteolytic Enzymes in Plants (//). 24 hours later, the results were : — Acid A Ikaline Neutral HCN ; f fibrin as before l strong tryptophane [ fibrin as before (faint tryptophane ( fibrin quite disintegrated (marked tryptophane Chlorof as before faint trypt. as before doubtful trypt. about half gone distinct trypt. NaF. mostly disintegrated faint trypt. as before doubtful trypt. mostly disintegrated faint trypt. The contents of all the bottles gave a good biuret-reaction at the close of the experiment. The alkaline bottles retained their reaction throughout. The results with fibrin not only serve to confirm those with Witte-peptone, but they give valuable information as to the nature of the action not only of the antiseptics but also of the reaction of the medium. With regard to the first point, it appears that neither chloroform nor NaF inhibits the peptoniz- ing action of papa'fn, but that they both (especially NaF) impede further proteolysis with the formation of tryptophane. With regard to the second point, it is clear that the presence of acid is altogether favourable, whilst the presence of alkali is as distinctly unfavourable, impeding even peptonization in the bottles containing either chloroform or NaF. These results suffice to make clear the reason of the failure to obtain the tryptophane-reaction in the experiments of Mendel and Underhill, and they establish the accuracy of my previous observations. They strikingly demonstrate the remarkably favourable effect of the presence of HCN upon the proteolytic activity of papain, as also the inhibitory effect of NaF. In view of these results, I thought it worth while to make comparative experiments with a number of the antiseptics in general use for these purposes. In the first series, Witte- peptone was the digestible material ; in the second, fibrin. Experiment with Witte-peptone. A clear solution (2 grms. in 200 cc. dist. water) of papain, and a clear solution of Witte-peptone (2 grms. in 200 cc. dist. water), were prepared : in the latter .1 grm. of citric acid was dissolved. 25 cc. of Vines— Proteolytic Enzymes in Plants (//). 607 each solution were placed in each of 8 bottles, and to each (except one, the control) one of the following antiseptics was added : NaF, 1 % ; Salicylic acid, 1 %; thymol, -5 % ; chloroform, -5% ; toluol, -5 % ; formalin, *8 %. After 7 hours’ digestion at 40° C., the tryptophane-reactions were : — Distinct ; HCN bottle. Faint; thymol, toluol, control, chloroform. None; Salicylic acid, NaF, formalin. 1 7 hours later, the reactions were : Strong ; HCN. Distinct ; thymol, toluol, control. Faint ; Salicylic acid, chloroform. None ; NaF, formalin. A similar series of experiments, in which fibrin (2 grms.) replaced the Witte-peptone, and in which a stronger solution of papain (4 grms. extracted with 200 cc. dist. water) was used, gave confirmatory results. Experiment with Fibrin. The same antiseptics in the same strength as before. After 7 hours’ digestion, the results were : — HCN ; fibrin completely disintegrated ; distinct tryptophane reaction. Salicylic acid ; fibrin unaffected ; no tryptophane. Thymol ; fibrin slightly attacked ; no tryptophane. NaF ; fibrin partly disintegrated; no tryptophane. Chloroform ; fibrin unaffected ; no tryptophane. Toluol; fibrin gelatinous ; no tryptophane. Formalin ; fibrin unaffected ; no tryptophane. Control ; fibrin largely disintegrated ; distinct tryptophane. 19 hours later, the results were essentially similar: the fibrin was rather more attacked in one or two cases, but it had not been com- pletely disintegrated in any but the HCN and the control bottles, and these were still the only bottles the contents of which gave any tryptophane-reaction, strong in the HCN bottle, distinct in the control. The contents of all the bottles gave good biuret-reaction. In these experiments the influence of HCN in promoting proteolysis by papain is very evident. In order to determine 6o8 Vines v — Proteolytic Enzymes in Plants {II). that HCN does not exercise any direct proteolytic action, the following experiment was made : — 30 cc. of a papain solution like the above were placed in each of 2 bottles, that in one of the bottles having been previously boiled : to each bottle were added 1 grm. Witte-peptone, *25 grm. citric acid, and 20 cc. dist. water containing HCN so that the percentage of HCN in the mixture was 0*2. After 18 hours’ digestion, the unboiled contents of the one bottle gave strong tryptophane-reaction, whilst the boiled contents of the other gave none. I then proceeded, for purposes of comparison, to make a similar experiment with the juice of the Pine-apple. 50 cc. of expressed juice were placed in each of 7 bottles, with 1 grm. of moist fibrin : in 5 of the bottles the juice was of natural acidity, and to each of these antiseptics were added respectively as follows: 0-2% HCN, 1% NaF, 0-5% thymol, 0-5 % toluol, 0-5% chloroform: the juice in the sixth bottle was neutralized and then made distinctly alkaline by the gradual addition of 1-7 grm. Na 2 Co 3 , when 0*2 % HCN was added : no antiseptic was added to the seventh bottle. After 24 hours’ digestion at 40° C., the results were as follows. The fibrin had been quite or almost completely dissolved in all the bottles : least in the NaF and chloroform bottles. The tryptophane- reactions were : — very strong in NaF, thymol, toluol, and chloroform bottles ; marked in the toluol bottle and in the alkaline HCN bottle ; less marked in the acid HCN bottle and in the bottle without anti- septic. These results are altogether contradictory to those obtained with papain : for in this case proteolysis was most active in the presence of NaF, and least active in the presence of HCN. It seems natural to infer that the difference in the behaviour of the two proteases with the two antiseptics indicates a funda- mental diversity in their properties. It is generally agreed that bromelin is a more active protease than papain, though no digestion-experiments have been made with equivalent weights of the pure substances ; and until that has been done, there is no real basis for comparison. There can, however, be little Vines . — Proteolytic Enzymes in Plants (II). 609 doubt that the undiluted juice used in this series of experi- ments contained a much higher percentage of protease than did the extracts of papain in the previous series ; and it seemed possible that the diverse results might be due rather to the relative amount of the proteases in the solutions than to a difference in their properties. With this possibility in view, I instituted the following experiments with papain-extracts of different strengths, and with diluted and undiluted Pine- apple juice, NaF and HCN being the antiseptics employed. Papain. 50 cc. of 4 % watery extract were placed in each of two bottles, together with 0*2 grm. citric acid and 1 grm. of moist fibrin : to one bottle o*5 grm. NaF (= 1%) was added, to the other 2*5 cc. of 4 % HCN (= 0-2 %). Two exactly similar bottles were prepared in which, however, the strength of the papain-extract was 2 %. After 18 hours’ digestion at 40°C., the fibrin was completely dis- solved in both the HCN bottles ; only partially dissolved in the NaF bottles. The tryptophane-reaction was strong in the bottle containing the 4 % extract and HCN ; distinct in the bottle containing the 2 % extract and HCN ; faint in both the NaF bottles. 30 hours later, the fibrin was completely dissolved, except for a small residue, in all the bottles. The tryptophane-reaction was strong in both the HCN bottles ; faint in both the NaF bottles. Bromelin. 50 cc. of undiluted Pine-apple juice were placed in each of 2 bottles with 1 grm. moist fibrin : to the one 0*5 grm. NaF 1 %) was added, to the other 2*5 cc. 4 % HCN (0-2 %). Two exactly similar bottles were prepared in which the juice had been diluted with an equal volume of distilled water. After 18 hours’ digestion, the fibrin was mainly dissolved in all the bottles. The tryptophane-reaction was strong in the bottle con- taining undiluted juice and NaF ; marked in the bottle containing diluted juice and NaF ; distinct in that containing undiluted juice and HCN ; faint in that containing diluted juice and HCN. 30 hours later, the fibrin was dissolved in all the bottles. The tryptophane-reaction was very strong in the NaF bottle with undiluted 6io Vines. — Proteolytic Enzymes in Plants (IP). juice, strong in the NaF bottle with diluted juice, marked in both the HCN bottles. From these experiments it is clear that the influence of such antiseptics as NaF and HCN on proteolysis depends, not upon the amount of the protease present, but upon the nature of the protease, probably upon its chemical constitution. The general conclusion to be drawn from all these experi- ments with various antiseptics is that these substances exert a considerable influence, greater than is usually supposed, upon proteolytic processes. It is, I think, made clear that in investigating the action of any protease, it is necessary that experiments should be conducted with more than one antiseptic before any conclusion as to the properties of the enzyme is arrived at. I am also justified in reasserting that all vegetable proteases, so far as they have been investigated, are essentially proteolytic ; and that no merely peptonizing protease has yet been discovered. I may incidentally mention here an experiment upon the action of Pine-apple juice at the ordinary temperature of the laboratory instead of in the incubator : that is, at about 17 0 C. instead of 40° C. The results show that proteolysis is effected under these conditions, but more slowly than at the higher temperature. 50 cc. of Pine-apple juice were placed in each of two bottles, with 1 grm. moist fibrin; to the one 0*5 grm. of NaF (= 1 %) was added, to the other 2-5 cc. of 4 % HCN (= 0-2 %). After 1 9 hours' digestion the fibrin was quite disintegrated in both : the NaF bottle gave distinct tryptophane-reaction, the HCN bottle gave no reaction. 29 hours later, the NaF bottle gave strong tryptophane-reaction, the HCN bottle a distinct reaction. Dahlia variabilis. The tuberous roots of the Dahlia have long been the subject of investigation on account of their peculiar chemical contents. They have largely provided the material for the Vines. — Proteolytic Enzymes in Plants (//). 6 1 1 study of inulin, though the discovery of the enzyme innlase was made by Green (1887) i n the tubers of the Jerusalem Artichoke (. Heliantlms tuber osns). But the fact of more immediate interest in connexion with the subject of the present paper is that Leitgeb ( 7 ) found the roots, in a state of rest, to contain considerable quantities of asparagin and tyrosin as nitrogenous reserve-material. On this ground the Dahlia-roots seemed likely to be promising material for digestion-experiments, which I have accordingly made, together with some incidental observations on the presence of tyrosin. The expressed juice of the tuberous roots immediately assumes a dark colour owing to the action of the oxidase which Bertrand (8) found to be present, and which he termed tyrosinase , upon the tyrosin in solution. On filtration, a brown, opalescent, distinctly acid liquid is obtained, which gives strong xanthoproteic reaction, strong Hofmanns reaction with Millon’s reagent, and oxidase-reaction with guaiacum, but no biuret-reaction : it gives a tryptophane-reaction which is not easy to perceive on account of the brown colour of the liquid. On boiling the juice there is a considerable precipitate : the clear filtrate gives the same Hofmann’s and xanthoproteic reactions as the unboiled liquid. These reactions, especially the Hofmann’s reaction with Millon’s reagent, in which a brilliant pink colouration appears on heating, followed by the formation of a similarly coloured precipitate, indicate the presence of tyrosin in considerable quantity. More definite evidence is afforded by the applica- tion of Morner’s ( 9 ) test. As this reagent is not yet well known, I give its preparation. It is a mixture of 1 vol. of formalin (40%) with 45 vols. of distilled water, and 55 of concentrated sulphuric acid. Heated with tyrosin, a striking green colour is produced. I found that on adding some of this reagent to Dahlia-juice, the green colour was developed without heating ; the effect of heating was to give rise to a brown colour, due probably to the action of the H 2 S 0 4 on the inulin present. T t 612 Vines . — Proteolytic Enzymes in Plants (//). Turning now to the question of the proteolytic activity of the juice, I may mention that Buscalioni and Fermi found the tuberous roots of the Dahlia to be proteolytically inactive, but this is not in accordance with my results. I made experiments (a) with the juice alone (autolysis) ; ( b ) with Witte-peptone added ; ( c ) with fibrin added ; in all cases there was distinct evidence of proteolysis. The material used was the root in the resting condition, and the experiments were carried on at intervals from January to March. Auiolysis. 40 cc. of slightly diluted expressed juice were placed in each of 4 bottles: to (1) nothing was added; to (2) HCN 0-2 %; to (3) citric acid 0-5 % ; to (4) HCN 0-2 %, and citric acid 0-5 %. After 21 hours’ digestion at 40°C., the contents of (1) and (2) gave a distinct tryptophane-reaction, those of (3) and (4) a marked reaction. 30 hours later, (1) and (2) still gave the same reaction, whilst that of (3) was marked, and that of (4) had become strong. Proteolysis of Witte-peptone . In each of four bottles were placed 50 cc. of expressed juice diluted with equal vol. of dist. water, and 0*5 grm. Witte-peptone: the further additions to the bottles were precisely as in the preceding experiment. After 4 hours’ digestion at 40°C., the tryptophane-reaction was strong in the bottle containing citric acid, and in that to which neither citric acid nor HCN had been added ; marked in the citric acid and HCN bottle; distinct in that to which HCN but no citric acid had been added. 19 hours later, the reactions were essentially the same. Fibrin . 4 bottles were prepared precisely as those in the preceding experi- ment, except that 1 grm. moist fibrin was substituted for the Witte- peptone. After 19 hours’ digestion at 40° C., the fibrin had become shrivelled and stringy in all the bottles, and did not appear to have been at all dissolved. The tryptophane-reactions were: — distinct in the citric acid and HCN bottle, as also in the bottle with HCN but no citric Vines. — Proteolytic Enzymes in Plants (II). 6 13 acid, and in the bottle to which neither citric acid nor HCN had been added ; marked in the bottle with citric acid but without HCN. 48 hours later, the fibrin presented the same appearance, and the tryptophane-reactions were : — marked in all the bottles except the one containing HCN but no citric acid, where it remained distinct. I have further succeeded in preparing a proteolytically active glycerin-extract from the roots. 100 grms. of the root, cut into small pieces, were macerated in strong alcohol for twenty-one hours, and then dried at room-temperature : the dried material, which weighed only 13 grms., was well triturated with 50 cc. glycerin, and left to stand for three days. The mass was then strained through muslin, yielding a turbid brownish extract, the activity of which was tested as follows : — 30 cc. of the glycerin-extract were mixed with 130 cc. chloroform- water, and 40 cc. of the mixture were placed in each of 4 bottles. To the liquid in No. 1, which was slightly acid, 0-2 grm. Witte-peptone was added: to No. 2, 0-2 grm. Witte-peptone, and 0-2 grm. citric acid (=o*5%): to No. 3, 0*2 grm. Witte-peptone and 0-2 grm. Na 2 C 0 3 (=0-5%) so that the reaction was distinctly alkaline: to No. 4 nothing was added. After 4 hours’ digestion at 40° C., the contents of Nos. 1, 3, and 4 gave a faint tryptophane-reaction ; those of No. 2, a distinct reaction. 19 hours later the tryptophane-reaction was distinct in No. 1, marked in No. 2, faint in Nos. 3 and 4. From these experiments it is clear that the tuberous root of the Dahlia contains an enzyme which proteolyses the proteids of the root ; that it also proteolyses Witte-peptone is shown by the rapid development of a more or less strong tryptophane-reaction when this material is presented to it. There is, however, no evidence that the protease attacks fibrin, for in no case did there appear to be any definite solution of it ; the tryptophane-reactions given by the contents of the bottles in the fibrin-experiments were so nearly the same as those given by the bottles in the autolysis-experiments that they do not appear to have been to any extent due to the presence of the fibrin. T t 2 6 14 Vines— Proteolytic Enzymes in Plants (II). Helianthus tuberosus. I have already stated (1) that the tissue of the tuber of this plant proteolyses Witte-peptone. I have since ascertained that the expressed juice of the tuber proteolyses Witte- peptone, as also its own proteids. In view of the presence of inulin in this tuber, I thought it worth while to determine whether or not the inulin were accompanied by tyrosin, as is the case in the tuberous root of the Dahlia. I found that there was no such storage of tyrosin in this plant. The expressed juice is a brown, turbid, slightly acid liquid ; it gives the oxidase-reaction with guaiacum, and strong xanthoproteic reaction. On boiling there is a dense pre- cipitate ; the clear filtrate gives faint tryptophane-reaction, no biuret, only a faint Millon’s reaction, and none with Morner’s reagent for tyrosin, in striking contrast to the juice of the Dahlia-root. Crambe maritima. The etiolated shoots of the Sea-kale occurred to me as probably interesting material for investigation. The expressed juice is a yellow acid liquid, giving good peroxidase but no oxidase-reaction with guaiacum ; it also gives weak xantho- proteic and Millon’s reactions. A precipitate is formed on boiling ; the filtrate gives no biuret, but faint tryptophane- reaction. Digestion-experiments showed that autolysis is feeble, but the proteolysis of Witte-peptone is active. 50 cc. of expressed juice, diluted with an equal vol. of dist. water, were placed in each of 4 bottles : to (1) only a little thymol was added ; to (2) a little thymol and 0-5 grm. Witte-peptone ; to (3) thymol, 0-5 grm. of Witte-peptone, and 0-25 grm. citric acid (= 0-5 %) ; to (4) 0*5 grm. Witte-peptone, 0*25 grm. citric acid, and HCN to 0-2 %. After 1 9 hours’ digestion at 40° C., (1) gave faint tryptophane-reaction ; (2) a strong reaction ; (3) and (4) a marked reaction. Vines. — Proteolytic Enzymes in Plants (//). 615 The action of the juice upon fibrin was then investigated. Inasmuch as in the previous experiment the activity of the juice had been found to be greatest in the bottle to which no acid had been added, no acid was added in this case : but the contents of the bottles were very distinctly acid at the close of the experiment. The result indicates that the juice does not act upon fibrin. 40 cc. of expressed juice, diluted with an equal vol. of dist. water, were placed in each of 3 bottles, with some thymol: to (1) nothing further was added; to (2) 0-5 grm. of Witte-peptone ; to (3) 1 grm. of moist fibrin. After 29 hours’ digestion at 40° C., (1) and (3) gave distinct tryptophane-reaction, (2) a strong reaction. The fibrin in (3) did not appear to have been attacked to any extent, so that the tryptophane- reaction was due to autolysis. Inasmuch as neither the enzyme of the Sea-kale, nor that of the Dahlia acts upon fibrin, they are to be referred, like those of many other plants (see my previous paper, 1), to the erepsin-group of proteases. Betula alba. I happened to have the opportunity of investigating the sap poured out by a ‘ bleeding 5 Birch-tree. The sap is a clear, yellowish, neutral liquid : it gives the peroxidase- but not the oxidase-reaction with guaiacum, also faint xanthoproteic and Millon’s reaction, no tryptophane or biuret-reaction, but strong sugar-reaction with Fehling’s solution. Digestion-experiments were made with and without added proteid (Witte-peptone and fibrin), the sap being acidified with citric acid or made alkaline with Na 2 C 0 3 , also with or without the addition of a few drops of HCN solution as an antiseptic, but in no case was any tryptophane-reaction observed, even when digestion was prolonged to forty-eight hours. The sap apparently contains no protease. 6 1 6 Vines . — Proteolytic Enzymes in Plants (II). List of References. 1. Vines: Proteolytic Enzymes in Plants; Annals of Botany, vol. xvii, 1903, p. 237. 2. Buscalioni and Fermi : Studio degli Enzimi proteolytici e peptonizzanti dei Vegetali ; Annuario del R. Istituto Botanico di Roma, vii, 1898, p. 99. 3. Vines : Tryptophane in Proteolysis ; Annals of Botany, vol. xvi, 1902, p. 1, 4. Martin : Papain Digestion ; Journ. of Physiol., v, 1884, p. 213: also, Nature of Papain, and its action on Vegetable Proteids ; Journ. of Physiol., vi, 1885, p. 336. 5. Mendel and Underhill : Observations on the Digestion of Proteids with Papain ; Trans. Connecticut Acad, of Arts and Sciences, xi, 1901. 6. Mendel : Observations on Vegetable Proteolytic Enzymes, with special refer- ence to Papain ; Amer. Journ. of Med. Sciences, Aug. 1902. 7. Leitgeb : Der Gehalt der Dahliaknollen an Asparagin und Tyrosin ; Mittheil. aus dem Bot. Inst, zu Graz, Heft 2, 1888, p. 215. 8. Bertrand : Sur une nouvelle oxydase ou ferment soluble oxydant, d’origine v^gdtale; Bull, de la Soc. Chimique, Paris, ser. 3, xv, 1896, p. 793. 9. Morner : Klein ere Mittheilungen : I. Farbenreaction des Tyrosins ; Zeitschr. f. physiol. Chemie, xxxvii, 1902, p. 86. NOTES THE DOUBLE PITCHERS OF DISCHIDIA SHELFORDII, sp. nov.— -A previous paper contained an imperfect account, founded upon herbarium material, of the double pitchers of four species of Dischidia, viz. D. complex from Malacca, the Phillippine D. pectenoides , and two undescribed Bornean species 1 . Mr. R. Shelford, M.A., Curator of the Sarawak Museum, has been so kind as to interest himself in the subject, and as a result of his endeavours complete herbarium material, as well as spirit specimens of a double-pitchered species from Kuching, have been received at Kew. These belong to a species not hitherto described, and are identical with Haviland’s specimen from the Kuching Lake, bearing the number 2015 2 . Upon these specimens is founded the description of the species which I have the pleasure of naming after Mr. Shelford, who has been the first to send to me the material which rendered a knowledge of the species possible. Dischidia Shelfordii, sp. nov. Planta epiphyta, volubilis, glabra. Folia normalia pauca, opposita, breviter petiolata, late triangularia vel suborbiculare, basi truncata, apice rotundata vel breviter apiculata, crassiuscula, arete nervata, L-J in. long. Ascidium maturum brevissime petiolatum, videtur solitarium in nodo, \\ poll, longum, 1 poll, latum, -J poll, crassum ; exterius late reniforme, colore lurido-purpureo suffusum, venis ramosis purpureis instructum (speciminibus in vini spiritu conservatis), apice invaginante introrsum et formante ascidium interius parvum. Cymae capituliformes, terminales in ramis axillaribus, 3-6- florae. Flores albidi (?), pedicellis brevissimis glabris crassiusculis suffulti. Calyx alte 5-lobatus ; lobi membranacei, oblongi, apice rotundati, carinati, glaberrimi, persistentes, circ. poll, longi. Corollae tubus urceolatus, quinquangularis, glaber, circ. 1 lin. longus ; lobi lanceolati, acuti, sub anthesin erecti, glabri, marginibus crassis, 1 Pearson, Journ. Linn. Soc. Bot., xxxv, 1902 ; pp. 375-390, with Plate IX. 2 Pearson, loc. cit., 376 (and footnote), 378, 379. [Annals of Botany, Vol. XVII. No. LXVII. June, 1903 ] 6i 8 Notes . circ. \ lin. longi. Coronae squamae, 5, angustae, tubo stamineo affixae, membranaceae, apice alte 2-fidea, lobis longiusculis recurvis. Anther ae erectae. Stigma complanatum, obsolete 2-lobatum, vix ex antheris exsertum. Folliculi tenues, teretes, leves, acuminati, i-|-2j poll, longi. Semina pilis longis albidis sericeis coronata. Borneo: Kuching, Shelford , near Kuching Lake, Haviland 2015. Mr. Shelford states that his specimen is epiphytic on a tree which he believes to be a species of Ficus. H. H. W. PEARSON. STUDIES IN THE MORPHOLOGY OF SPORE-PRODUCING MEMBERS. NO. V. GENERAL COMPARISONS, AND CON- CLUSION \ — This concluding Memoir contains a general discussion of the results acquired in the four previous parts of this series, and of their bearing on a theory of sterilization in the sporophyte. The attempt is made to build up the comparative morphology of the sporophyte from below, by the study of its simpler types ; the higher and more specialized types are left out of account, except for occasional comparison. It is assumed for the purposes of the discussion that alternation of generations in the Archegoniatae was of the antithetic type, and that apogamy and apospory are abnormalities, not of primary origin. After a brief allusion to facts of sterilization in the sporogoma of Bryophytes, the similar facts are summarized for the Pteridophytes. It has been found that examples of sterilization of potentially spore- genous cells are common also in vascular plants, while occasionally cells which are normally sterile may develop spores. Hence it is concluded that spore-production in the Archegoniate plants is not in all cases strictly limited to, or defined by, preordained formative cells, or cell-groups. A discussion of the archesporium follows, and though it is found that in all Pteridophyta the sporogenous tissue is ultimately referable to the segmentation of a superficial cell, or cells, still in them, and, indeed, in vascular plants at large, the segmenta- tions which lead up to the formation of spore-mother-cells are not comparable in all cases; in fact, that there is no general law of 1 Abstract of a paper read before the Royal Society on February 12, 1903, reprinted from the Proceedings. Notes. 619 segmentation underlying the existence of that cell or cells which a last analysis may mark out as the ‘ archesporium ’ ; nor do these ultimate parent-cells give rise in all cases to cognate products. Therefore it is concluded that the general application of a definite term to those ultimate parent-cells which the analysis discloses has no scientific meaning, beyond the statement of the histogenic fact. Further, it is shown that the tapetum is not a morphological constant, but varies both in occurrence and origin; that even the individuality of the sporangium is not always maintained. All that remains then as the fundamental conception of the sporangium in vascular plants is the spore-mother-cell, or cells, and the tissue which covers them in, for such cells are always produced internally. The definition of the sporangium may then be given thus : ‘ Wherever we find in vascular plants a single spore-mother-cell, or connected group of them, or their products, this with its protective tissues constitutes the essential of an individual sporangium/ From the point of view of a theory of sterilization such sporangia may, at least in the simplest cases, be regarded as islands of fertile tissue which have retained their spore-producing character, while the surrounding tissues have been diverted to other uses. It will be seen later how far this view will have to be modified in the more complex cases. In a second section of the Memoir the variations in number of sporangia in vascular plants are discussed ; the methods of variation may be tabulated as follows, under the heads of progressive increase and decrease : — I. Increase in Number of Sporangia . (a) By septation, with or without rounding off of the individual sporangia. (b) By formation of new sporangia, or of new spore-bearing organs, which may be in addition to, or interpolated between those typically present. ( c ) By continued apical, or intercalary growth of the parts bearing the sporangia. (d) By branching of the parts bearing the sporangia. (e) Indirectly, by branchings in the non-sporangial region resulting in an increased number of sporangial shoots ; this is closely related to ( c ) and (d). 620 Notes . II. Decrease in Number of Sporangia. (/) By fusion of sporangia originally separate. (g) By abortion, partial or complete, of sporangia. (k) By reduction or arrest of apical or intercalary growth in parts bearing sporangia. (i) By fusion of parts which bear the sporangia or arrest of their branchings. (J) Indirectly, by suppression of branchings in the non-sporangial region, resulting in decreased number of sporangial shoots ; this is closely related to ( h ) and (i). We are justified in assuming that (subject to the possibility of other factors having been operative, of which we are yet unaware) the condition of any polysporangiate sporophyte as we see it is the resultant of modifications such as these, operative during its descent. The problem will, therefore, be in each case to assign its proper place in the history to any or each of these factors. It is pointed out that in homosporous types, which are certainly the more primitive, the larger the number of spores the better the chance of survival, and hence, other things being equal, increasing numbers of spores and of sporangia may be anticipated ; but in the heterosporous types reduction in number both of spores and of sporangia is frequent. The former will accordingly illustrate more faithfully than the heterosporous forms the story of the increase of complexity of spore-producing parts. The general method put in practice here is to regard homosporous forms as in the upgrade of their evolution, as regards their spore-producing organs, unless there is clear evidence to the contrary. The onus probandi lies rather with those who assume reduction to have taken place in them. A summary of evidence of variation in number of sporangia by any of these methods is then given for the Lycopodineae, Psilotaceae, Sphenophylleae, Ophioglossaceae, Equisetineae, and Filicineae; followed in each case by a theoretical discussion of the bearing of that evidence on the morphology of the spore-producing members. The general result is that all of them, including even the dorsiventral and megaphyllous types, are referable to modifications of a radial strobi- loid type ; progressive elaboration of spore-producing parts, followed by progressive sterilization, and especially by abortion of sporangia in them, of which there is frequent evidence, together with the acquire- Notes . 62 1 ment of a dorsiventral structure, may be held to account for the origin of even the most complex forms. But the vegetative organs once formed may also undergo elaboration and differentiation pari passu with the spore-producing organs, a point which has greatly complicated the problem, especially in the higher forms ; all roots are probably of secondary origin ; facts of interpolation of additional sporangia, especially in Ferns, and of apogamy and apospory, are also disturbing influences, which have probably been of relatively recent acquisition. A comparison is drawn as regards position, physiological and evolutionary, in the sporophyte, between the fertile zone in certain Bryophytes and the fertile region of certain simple Pteridophytes, e.g. the Lycopods; though no community of descent is assumed, the relation of the reproductive to the vegetative regions is the same. In the Bryophytes that region is regarded as a residuum from progressive sterilization ; it is suggested that the same is the case for a strobiloid Pteridophyte, such as Lycopodium. The theory of the strobilus, based on this comparison, is that similar causes would lead to the decentralization of the fertile tissue in the primitive Pterido- phytes as in the Bryophytes, and result in the formation of a central sterile tract, with an archesporium at its periphery; that such an archesporium, instead of remaining a concrete layer as it is in the larger Musci, became discrete in the Lycopods ; that the fertile cell- groups formed the centres of projecting sporangia, and that they were associated regularly with outgrowths, perhaps of correlative vegetative origin, which are the sporophylls. Whether or not this hypothesis of the origin of a Lycopod strobilus approaches the actual truth, comparison points out the genus Lyco- podium as a primitive one, characterized by more definite numerical and topographical relation of the sporangia to the sporophylls than in any other type of Pteridophyta. Then follows, as a consequence of comparison, the enunciation of a theory of the sporangiophore, a word which is here used in an extended sense to include not only the spore-producing organs of Psilotaceae, Sphenophylleae, Ophioglossaceae, and Equisetaceae, but also the sori of Ferns. The view is upheld that all these are simply placental growths, and not the result of ‘ metamorphosis ’ of any parts or appendages of prior existence ; that the vascular supply, which is not always present, is not an essential feature ; that they are seated at 622 Notes. points where, in the ancestry, spore-production has been proceeding on an advancing scale ; hence they do not occupy any fixed and definite position. It seems probable that at least a plurality of sporangia existed on primitive sporangiophores, and that where only one exists that condition has been the result of reduction. The above theories are then applied to the several types of Pterido- phyta. The Lycopods, Psilotaceae, Sphenophylleae, and Ophio- glossaceae may be arranged as illustrating the increased complexity of the spore-producing parts, and of the subtending sporophylls ; the factors of the advance from the simple sporangium to the more com- plex sporangiophore are, septation, upgrowth of the placenta with vascular supply into it, and branching, with apical growth also in the Ophioglossaceae. But even in the most complex forms the sporan- giophore may be regarded as a placental growth, and not the result of transformation of any other member. In the case of Helminthostachys the marginal sporangiophores are regarded as amplifications from the sunken sporangia of the Ophio- glossum type ; in Equisetuvi they are regarded as being directly seated on the axis, and having originated there by a similar progression ; they would thus be non-foliar. It is pointed out that though a foliar theory would be possible for Equisetum itself, it is not applicable to the facts known for the fossil Calamarieae, which are so naturally related to it. Thus the strobilus of the Equisetineae is of a rather different type from that of the Lycopods, Psilotaceae, or even the Ophioglossaceae, in all of which there is a constant relation of the spore-producing parts to the leaves ; in the Equisetineae no such con- stant relation exists ; the leaves and sporangiophores may be in juxta- position, as in Calamostachys, without exactly matching numerically; or the sporangiophores may occur in larger numbers and in several ranks, between successive leaf-sheaths, as in Phyllotheca and Bornia ; or without any leaves at all, as in Equisetum . Thus, on a non- phyllome theory the latter may be held to be only an extreme case of what is seen in certain fossils. The Ferns, notwithstanding their apparent divergence of character from other Pteridophytes, may also be regarded as strobiloid forms, with greatly enlarged leaves; the primitive sori of the Simplices resemble the sporangiophores of other Pteridophytes ; the more com- plicated soral conditions of the Gradatae and Mixtae were probably derivative from these, the chief difference being due to the interpolation Notes. 623 of new sporangia, an innovation which is in accordance with biological probability, as well as with the palaeontological record. The effect of the results thus obtained on the systematic grouping of the Pteridophytes is then discussed; it is pointed out that the Lycopods, Psilotaceae, Sphenophylleae, Ophioglossaceae, and Filices illustrate lines of elaboration of a radial strobiloid type, with increas- ing size of the leaf. The division of Pteridophyta by Jeffrey, on anatomical characters, into small-leaved Lycopsida and large-leaved Pteropsida is quoted ; but it is concluded that the anatomical distinc- tion of Jeffrey does not define phylogenetically distinct races, but is rather a register of such leaf-development as differentiated them from some common source. It is contended that the Ophioglossaceae and Filices, which constitute Jeffrey’s Pteropsida, are not necessarily akin on the ground of their large leaves, and consequent phyllosiphonic structure ; but that they probably acquired the megaphyllous character along distinct lines. The opinion of Celakovsky is still held, ‘that the Lycopods are probably of living plants, the nearest prototypes of the Ophioglossaceae/ The more recent investigations of Jeffrey and of Lang have shown, however, that in the gametophyte of the Ophio- glossaceae there is an assemblage of ‘ Filicinean ' characters, which differ from those of Lycopodium itself. But Celakovsky’s comparison is with the Lycopods , not with the genus Lycopodium ; so far as the facts go, increasing ‘ Filicinean ’ characters of the gametophyte follow in rough proportion to the larger size of the leaf; thus from Lsoetes we learn that a combination of cross-characters is found in a mega- phyllous Lycopod type. What we find in the Ophioglossaceae is that in conjunction with their more pronounced megaphyllous form, still retaining, however, the Lycopodinous type of the sporophyte, they show more pronounced ‘ Filicinean ’ characters of the gametophyte and of the sexual organs. It is unfortunate that the facts relating to the gametophyte of the Psilotaceae and Sphenophylleae are not avail- able in this comparison. What the meaning is of this parallelism between leaf-size and characters of the sexual organs it is. difficult to see ; a further difficulty in its interpretation lies in the fact that for the Equiseta the parallel- ism does not hold ; there ‘ Filicinean ’ characters of the gametophyte accompany entirely non-Filicinean characters of the sporophyte, the latter showing nearer analogy to the Lycopods than to the Ferns. Such cross-characters are difficult to harmonize with any phylogenetic 624 Notes . theory ; on account of them, the Equisetineae are placed in an isolated position, and in the same way, though with less pressing grounds, a separate position should be accorded to those types which lie between the extremes of Ly copods and Ferns, in proportion as the cross- characters are more or less pronounced. On this basis the Isoetaceae would probably best take their place as a sub-series of the Lycopodiales, Ligulatae ; the Psilotaceae and Sphenophylleae would constitute a series of Sphenophyllales, separate from, but related to, the Lycopodiales. The Ophioglossaceae would form an independent series of Ophioglossales, more aloof than the Sphenophyllales from the Lycopodiales, but not included in the Filicales. The actual connexion of these series by descent must remain open ; it is quite possible that some or all of them may have originated along distinct lines from a general primitive group, which may be provisionally designated the Protopteridophyta ; these were probably small-leaved strobiloid forms, with radial type of construction, and with the sporangia disposed on some simple plan. The grouping arrived at in these Memoirs may be tabulated as follows : — PTERIDOPHYTA. I. Lycopodiales. (a) Eligulatae. Lycopodiaceae. ( b ) Ligulatae. Selaginellaceae. Lepidodendraceae. Sigillariaceae. Isoetaceae. II. Sphenophyllales. Psilotaceae. Sphenophyllaceae. III. Ophioglossales. Ophioglossaceae. IV. Filicales. (a) Simplices. Marattiaceae. Osmundaceae. F. O. Bower. Schizaeaceae. Gleicheniaceae. Matonineae. ($) Gradatae. Loxsomaceae. Hymenophyllaceae. Cyatheaceae. Dicksonieae. Dennstaedtiinae. Hydropterideae (?). (c) Mixtae. Davallieae. Lindsayeae. Pterideae, and other Poly- podiaceae. V. Equisetales. Equisetaceae. Calamarieae. Notes , 625 ON LAGENOSTOMA LOMAXI, THE SEED OF LYGINO- DENDRON h— ' The existence in Palaeozoic times of a group of plants (the Cycadofilices of Potonid) combining certain characters of Ferns and Gymnosperms, has been recognized for some years past by various palaeo-botanists 2 . The group in question embraces a number of genera, among which Medullosa , Heierangium, Calamopitys , and Lyginodendron may be mentioned ; the fern-like foliage of these plants is placed according to its external characters in the form-genera Alethopteris , Neuropteris , Sphenopleris, and others. The evidence for the intermediate position of the Cycadofilices is extremely strong, but at present it is drawn entirely from a detailed comparison of their vegetative organs, especially as regards their anatomical characters. In no case, as yet, is the fructification of any member of the group known with certainty ; such indications as have hitherto been detected are still in need of corroboration. Thus, the suggestion has been made that the large seed, Trigonocarpon olivae- forme , may have belonged to some member of the genus Medullosa 3 ; and in the case of Lyginodendron itself there is fairly strong reason to believe that one form of fructification (in the light of the observations to be described below, presumably the male), may have been of the Calymmatotheca type 4 , a type, however, of which the organization is not yet fully understood. In the absence of satisfactory data as to the fructification, so high an authority as M. Zeiller has expressed a doubt whether the Cycadofilices were, after all, anything more than a specialized group of Ferns 5 . A re-examination of the seeds, placed by Williamson in his genus Lagenosioma , has revealed unexpected points of agreement between the structure of the envelopes of certain of these seeds on the one hand, and that of the vegetative organs of Lyginodendron on the other. 1 Read before the Royal Society on May 7, 1903 ; reprinted from the Proceedings. 2 Williamson, Organization of the Fossil Plants of the Coal-measures, Pt. XIII, Phil. Trans., B, vol. clxxviii, p. 299, 1887; Solms-Laubach, Fossil Botany, 1887, Engl, ed., pp. 141, 163; Williamson and Scott, Further Observations on the Organization of the Fossil Plants of the Coal-measures, Pt. Ill, Phil. Trans., B, vol. clxxxvi, p. 769, 1895 ; Potonie, Lehrbuch der Pflanzenpalaeontologie, p. 160, 1899; Scott, Studies in Fossil Botany, pp. 307, 514, 1900. 3 G. Wild, On Trigonocarpon olivaeforme , Trans. Manchester Geol. Soc., vol. xxvi, 1900. 1 Scott, Studies, p. 334 ; Miss Benson, The Fructification of Lyginodendron Oldkamium, Ann. of Bot., vol. xvi, p. 575, 1902. 5 Zeiller, Elements de Paleobotanique, 1900, p. 370. 626 Notes . Two species of Lagenosloma ( L . ovoides and L. physoides ) were described by Williamson 1 ; a third species, the subject of the present note, was left undescribed by him, though in his MS. catalogue he named it, after its discoverer, Lagenostoma Lomaxi , a name which we here provisionally adopt. This seed occurs in calcareous nodules of the lower Coal-measures, and chiefly at Dulesgate, in Lancashire. In general structure the seed L. Lomaxi agrees with L. ovoides. It is an orthotropous seed, circular in transverse section, and broadest midway between base and apex. The height of the seed slightly exceeds the diameter, and in general form it may be com- pared with a Jaffa orange. Its height in full-sized specimens is about 5J mm., the diameter at the equator 4J mm. Many of the specimens that have passed through our hands show signs of having become detached through the agency of a layer of separation and bear a low conical papilla centrally placed at the chalazal end, beneath which the actual layer of abscission was situated. In the most general relations of its organization the seed approaches the Gymnosperm type in that the integument and nucellus are distinct from one another in the apical region only, whilst the body of the seed, which contains the large single macrospore with traces of pro- thallial tissue, shows complete fusion of the integumental and nucellar tissues. But in other respects the seed is remarkable. The free portion of the nucellus which stands above the macrosporc is conical in form, its base is about 0-75 mm. across, and its height somewhat greater. The tapering apex reaches to the exterior, plugging the micropylar aperture like a cork. The whole of this structure, the ‘ lagenostome ’ of Williamson, constitutes a pollen-chamber, owing to the separation of the nucellar epidermis from the underlying parenchy- matous body of the free part of the nucellus. The pollen-chamber thus has the form of a bell-shaped cleft situated between the persistent epidermis and the central cone of nucellar tissue. Access to the chamber is gained at the apex, which is open, and pollen-grains are found in its lower part. The integument, which is a simple shell where fused with the nucellus, becomes massive and complicated in its free part which corresponds to the upper fifth of the seed. In this region it is usually composed of nine chambers radially disposed around 1 Organization, Pt. VIII, Phil. Trans., vol. clxvii, p. 233, Figs. 53-75, and 77- 79, 1877; Pt. X, Phil. Trans., Pt. II, 1880, p. 517, Figs. 61-63. See Oliver, New Phytologist, vol. i, no. 7, 1902. Notes . 627 the micropyle. The existence of these chambers is indicated on the outside surface of the seed by the presence of nine little ridges dis- posed like the rays of a star around the micropyle, but dying out almost at once. These ridges over-lie the partitions of the chambered portion of the integument just as do the stigmatic bands the septa of a poppy capsule. The whole structure from within is like a fluted dome or canopy, the convexities of which correspond to the chambers, and actually engage with broad low grooves on the surface of the wall of the pollen-chamber. The vascular system of the seed enters as a single supply-bundle at the chalazal papilla, and branches, a little below the base of the macro- spore, into nine radially-running bundles. Each of these bundles passes, without further branching, to the apex of the seed, running outside the macrospore and a little distance below the surface. At the canopy the bundles enter the chambers and end at the tips. Lagenostoma Lomaxi was thus a seed or seed-like structure detached as a whole and containing pollen-grains in the remarkable cleft-like pollen-chamber ; the integument in its free part, when compared with that of Williamson's Lagenostoma physoides , suggests a number of originally free arms or processes that have become ’laterally fused into a complex chambered organ. The seed, Z. Lomaxi , is in some cases still attached to its pedicel 1 ; the great peculiarity of this seed, as compared with other members of the genus, is that when young, and sometimes even at maturity, it is found enclosed in an envelope or cupule, springing from the pedicel just below the base of the seed, and extending above the micropyle — at least in young specimens. The cupule appears to have been ribbed below, and deeply lobed in its upper part ; in form it may be roughly compared to the husk of a hazel-nut — of course on a very small scale. The pedicel and cupule bear numerous capitate glands, of which some are practically sessile, others shortly stalked, while in others again the stalk is of considerable length. The head, or secreting portion of the gland, which is spherical in form, is almost invariably empty, only the multicellular wall persisting. The tissue of the stalk of the gland, consisting of many layers of cells, is preserved, though in a somewhat disorganized state. These cupular glands present the closest agreement in size, form, 1 Cf. Williamson, loc. cit., Pt. VIII, Fig. 68 (Z. ovoides). U U 628 Notes . and structure with the glands which occur on the vegetative organs of Lyginodendron Oldhamium 1 , and which are especially abundant on the particular form of that plant found in association with Lagenostoma Lomaxi. Both on petiole and cupule the majority of the glands are short, those which are not sessile being commonly about 0-4 mm. in height. Long-stalked glands, exceeding a millimetre in height, some- times occur both on the vegetative organs and on the cupule. The dimensions of the head of the gland agree exactly on cupule and petiole, the diameter averaging about 0-2 mm. in each case. In both, the stalk is usually somewhat narrower than the head, except at the base, where it is often considerably enlarged. On the stem, as might be expected, the glands are usually somewhat larger than on petiole or cupule. As. a rule, the structure of the glands on the vegetative organs is well preserved, the secretory tissue in the head being perfect. But occasionally the vegetative glands are found in the same state of preservation as those on the cupule, with the head hollow, owing to disappearance of the secretory mass. Where we thus have the two organs in a corresponding state of preservation, the agreement between the vegetative glands of Lyginodendron and those on the cupule of Lagenostoma Lomaxi is found to be exact. There is no other known plant from the Coal-measures with glands at all similar to those described, nor is it likely that any unknown Gymnosperm should so exactly resemble Lyginodendron in these characters. On the ground, then, of the glandular structure we are led to the conclusion that the seed Lagenostoma Lomaxi can have belonged to no other plant than Lyginodendron Oldhamium, and more particularly to the glandular form of that type with which the seed is associated. The state of preservation of the glands and of the cupule as a whole, indicates clearly that this organ, as we find it, was in an effete condition, having, no doubt, already discharged its functions while the seed which it protected was still quite young. The vascular system of the cupule was well developed, and is very fairly preserved. A number of bundles branched off from the main strand of the pedicel, and traversed the cupule throughout its whole 1 It has long been realized that the name Lyginodendron Oldhamium charac- terizes a type rather than a species. It is probable that the very glandular form occurring at Dulesgate may deserve specific rank. Notes . 629 extent. The structure of the large bundle, seen in the pedicel, agrees with that of a petiolar strand in Lyginodendron. The minute characters of the tracheides are also in close agreement with those observed in the xylem of the foliar organs of the same plant Hence, characters presented by the internal anatomical structure strengthen the conclusion drawn from a comparison of the glands, and thus further support the attribution of Lagenostoma Lomaxi to Lyginodendron. The evidence thus indicates that in a transitional type, such as Lyginodendron Oldhamium , with leaves wholly fern-like in structure and form, but with decided Cycadean as well as Filicinean characters in the anatomy of stem and root, the seed habit had already been fully attained, as fully, at any rate, as in any known Palaeozoic Gymnosperm. Lyginodendron retains, so far at least as its vegetative structure is concerned, the intermediate position already assigned to it, but whereas the fern-like characters have hitherto seemed to preponderate, the discovery of the seed inclines the balance strongly on the Gymnospermous side. It is not likely that Lyginodendron stood alone in this ; we must now be prepared to find, what has long been recognized as a possibility, that many of the plants grouped under Cycadofilices already possessed seeds, and thus that a consider- able proportion of the so-called ‘fern-fronds’ of the Palaeobotanist really belonged to Spermophyta. It is at present impossible to say at what stage in the evolution of the Fern-Cycad phylum the great change in reproductive methods came, whether it followed in the wake of general anatomical advance, or vice versa . The discovery of further evidence as to the reproductive processes of these ancient plants is likely to yield interesting results. The authors are much indebted to Miss Marie Stopes for her valuable aid in the examination of the numerous sections in the Williamson and various other Collections. Mr. J. Lomax deserves high praise for his good judgement and skill in collecting and preparing the material for the investigation. A full account of the fossils dealt with in the present note is in preparation, and will shortly be submitted to the Royal Society. F. W. OLIVER. D. H. SCOTT. Further Observations on the Phytoplankton of the River Thames. BY F. E. FRITSCH, B.Sc., Ph.D., F.L.S., Demonstrator in Botany , University College , London. T HE present year, with its unusually great rainfall and consequent heavy floods, has not been very favourable for comparative investigations of the river Plankton. The disturbing influence due to the height of the water and the strength of the current has been very noticeable in some of the samples collected, especially in those of May 2 . The speed of the current on that day was quite four times the usual one, and it is a well-known fact that the quality of the Plankton is considerably dependent on the rate of the stream (cf. Zacharias, ’98, p. 46 ; Zimmer, ’99, p. 7 ) ; a con- tinuation of such conditions for several days would probably have a very considerable effect on the composition of the Plankton, and this would most likely last for some time after the restoration of the normal state of affairs. It is therefore probable that, although the main features of the periodicity are sufficiently evident, observations under more normal conditions would have disclosed a number of minor points which have been obscured this year. The object of the present paper is primarily to touch upon the main points in the periodical development of the Plankton of the River Thames. Detailed investigations of the periodicity of river Plankton as yet scarcely exist, although Schroder has examined the [Annals of Botany, Vol. XVII. No. LXVIII, September, 1903.] X X 632 Fritsch. — Further Observations on the Oder to some extent from this point of view, and observations of this kind are at present being carried out on the river Volga (cf. Zykoff, '02, p. 60). With regard to the Oder at Breslau, Schroder (’ 98 , p. 525, ’ 99 , pp. 22-23), gi ves the following data : — I. December-February : — nothing or exceptionally Synura and Eudorina. II. March-May : — Synedra and a few brown Flagellates. III. June-August: — Asterionella\ a few green and occa- sional blue-green forms. IV. September-November : — Synedra and a few brown Flagellates. During the winter months the only living elements occur- ring in the Plankton are a few Rotifers, intermingled with large quantities of organic detritus and muddy particles, whilst Algae are almost alone represented by detached portions of filamentous forms. During March Melosira varians and Fragilaria virescens appear in some quantity, but near the end of the month Synedra delicatissima is the most abundant form ; only a few specimens of green Algae ( Chlamydomonas tingens , Pandorina morum, Eudorina elegans , and Volvox minor) occur, whilst Flagellates are rather commoner at this time of the year ( Synura uvella , Uroglena Volvox , Dinobryon sertidaria and Chrysomonas ovata). In the summer months Asterionella plays an exceedingly important part, and is accompanied by a quantity of other Diatoms ( Diatome tenue , Fragilaria capucina and F. crotonensis , Melosira gramdata , Stephanodiscus Flantzschianus) ; of the green forms Actin- astrum Hantzschii , var .jluviatile, and Dictyosphaerium Ehren- bergii , alone are at all abundant. As the autumn comes on the Plankton again acquires the spring character, and by a decrease in number of individuals gradually merges into that of the winter months. In the Danube, the Plankton of which has been examined by Brunnthaler (’00, pp. 310-311), the periodicity is somewhat different. In the clear water, occurring during the winter months, life is almost entirely wanting. In February Synedra Phytoplankton of the River Thames 633 appears, and at the same time a few individuals of Melosira. In the next months Melosira and Fragilaria increase in numbers, whilst the prevalent Asterionella of the succeeding summer months is as yet only slightly represented. In the height of the summer this latter form is accompanied by Ceratium , Dinobryon , Clathrocystis , and Fragilaria , in sub- ordinate numbers. With the autumn a decrease in number of individuals again becomes noticeable. Green forms only occur in any considerable amount during the summer months. To come now to the River Thames (see table), an important difference in contrast to the two rivers just discussed at once appears. There is a well-marked living Plankton all the year round ! The Diatoms, which form such a very large per- centage of the organic life of the Thames, are always present in appreciable numbers, even though from December to February about two-thirds of the individuals are dead and only represented by an empty frustule. At the same time, however, more or less abundant living representatives of all the species mentioned in the table for these months were observed, and samples, when examined under the microscope, always exhibited a number of live Diatoms in the field of view. This difference in the Thames Plankton as opposed to that of the Oder and Danube may most probably be ascribed to the mildness of our winter in contrast to the continental one ; for the sample collected on February 4, 1903 a few days after the cessation of a heavy frost, showed no change in the living element in the river, and it is only rarely that we exceed the degree of cold attained on this occasion. It is easy to understand how a frost of long duration, con- verting the backwaters and other sources of the river’s Plankton into a thick sheet of ice, would reduce the organic life in the river to a minimum by the temporary congealment of the reservoirs, from which it is in the main derived ; this is undoubtedly the case with the continental rivers, and it will be interesting to see what effect a protracted frost (of say three to four weeks), as occasionally occurs, will have on the Plankton of the Thames. X x 2 634 Fritsch . — Further Observations on the The following observations on the periodicity of the Thames Plankton were all made on the stretch of river lying between Teddington Lock and Kingston, and were carried out on seven separate occasions, from October to the beginning of July, at intervals of from one to two months. More frequent visits would have been desirable, but were prevented by the state of the river ; unfortunately it is also impossible to undertake any further investigations during this year, and I have therefore added the results of my dredging in July of last year (Fritsch, ’02), to complete the table to some extent. These latter were obtained from the river below Teddington Lock, the Plankton of which, however, shows no marked difference from that above the lock. All the samples were taken from the surface-layers only. In the samples, collected in October, abundant life was still present ; in addition to a number of green forms, of which Pandorina morum and Pediastrum Boryanum were most frequently met with, the Diatoms, Melosira varians and Fragilaria virescens , were exceedingly common. The three species of Surirella and Stephanodiscus Hantzschianus are also very characteristic of the Plankton at this time of the year, whilst other rather abundant forms are Synedra Ulna , Nitzschia sigmoidea , and Pleurosigma attenuatum . On the whole it is scarcely possible at this time to point out any one species as preponderating considerably over the others, although perhaps the two filamentous Diatoms are the most striking forms in the samples collected in this month. In December the green and blue-green forms had become ex- ceedingly rare, whilst the Diatoms, as already stated above, although still occurring in appreciable numbers, are to a con- siderable extent present as empty frustules. Melosira varians is still very abundant, whilst Fragilaria virescens is less evident, and the species of Surirella are decreasing in numbers. The most noticeable point about the Plankton at this time of the year, however, is the appearance of Asterionella gracillima in small numbers ; no trace of it was observed in the October samples. In February the Plankton practically Phytoplankton of the River Thames. 635 Table illustrating periodicity of Thames Plankton 1 2 3 4 . §o HO W . II • o o 8g Pt* d II I. Chlorophyceae. Scenedesmus quadricauda (Turp.), Breb. . . r. r. i. — i. - r. rc. Pediastrum Boryanum (Turp.), Men. . . . rc. r. i. vr. i. rc. rc. c „ pertusum , Ktz — — i. — rc. rr. c. „ pertusum, v ar. clathratum , Braun rr. — — — — rr. rr. — C hlamydomonas Braunii , Gorosch. . . . r. — — — — rc. — — Eudorina elegans , Ehrb. — — vr. — rr. r. r. Pandorina morum , Ehrb — — i. — — r. rc. Gonium pectorale, Mull. . — — — — — — vr. - II. CONJUGATAE. Closterium acerosum (Schrank), Ehrb. . . . r. — — — — — — vr. ,, moniliferum (Bory), Ehrb. . . . rr. — — — — rc. — vr. III. Bacillariales. Coscinodiscus radiatus, Ehrb vr. rc. Stephanodiscus Hantzschii , Grun c. rr. rc. — — rc. ? Melosira moniliformis (Mull.), Ag. . . . rr. rr. rc. rc. rc. rr. r. rc. ,, varians, Ag vc. vc 5 . c 5 . c. a. a. rc. c. Campylodiscus noricus, Ehrb. . rc. rr. r. rc. rc. rr. r. rc. Surirella biseriata , Breb c. c. rc. rc. rr. rr. r. rc. „ ovalis , Br6b „ splendida (Ehrb.), Ktz c. c. rr. rc. rr. r. r. c. c. rc. rr. rc. rr. rc. r. r. Cymatopleura Solea (Breb.), Sm rr. r. r. r. r. rr. — r. Cymbella gastroides , Ktz r. rr. rr. rr. — — — rc. Amphora ovalis , Ktz rr. rr. rr. rc. rr. rr. r. rc. Fragilaria virescens , Ralfs vc. c. rc. c. rc. rc. r. c. Grammonema spec . (long cell = 16 f) . . . rc. rc. rc. r. — — — — Pleurostaurum acutum (Sm.), Rabenh. . . r. r. rc. rc. — — vr. Synedra Acus , Ktz _ — — rc. rr. rr. a. 1 „ Acus , var. delicatissima , Sm. . . . _ — — rc. rr. _ c. „ Ulna , Ehrb. ........ c. c. rc. rc. c. c. a. rc. Asterionella gracillima, Heib — rc. c. r. — — — Nitzschia sigmoidea (Nitzsch), Sm c. c. c. rc. rc. rc. r. rc. Pinnularia viridis (Ehrb.), Rabenh. . . . — — — r. — — vr. Pleurosigma attenuatum (Ktz.), Sm. . . . c. c. c. rc. rc, rc. r. rc. ,, Fasciola (Ehrb.), Sm Tabellaria fenestrata, Ktz — — — rr. — _ __ - — - rr. rr. r. - — IV. SCHIZOPHYCEAE. Microcystis marginata (Men.), Kirchn. . . i. _ _ _ Merismopoedia glauca (Ehrb.), Nag. . . . r. vr. — - - - — — V. Flagellatae. Euglena viridis , Ehrb Phacus pleuronectes, Nitzsch vr. i. _ rc. r. vr. r. Synura Volvox , Ehrb — — — vr. — — rc. r. 1 a. = abundant ; vc. = very common ; c. = common ; rc - rather common ; rr. = rather rare ; r. = rare ; vr. = very rare ; i. = isolated. 2 The weather had only just become cold the day before, having been mild and foggy previously ; so that not too much stress should be laid on this temperature. 3 River high and current very strong. 4 Added in order to complete table as far as possible, cf. text. 5 With auxospores. 636 Fritsch . — Further Observations on the consisted of Diatoms only ; the green species, mentioned in the table, were both only observed once, groups of green Pleurococcoid cells being somewhat more frequent. Of the Diatoms observed, about two-thirds of the individuals were dead ; Melosira varians , Fragilaria virescens , and the species of Surirella , had decreased very much in amount, whilst Asterionella gracillima is far commoner, being very character- istic of the Plankton at this stage. Its reign is apparently short, however, for samples collected in the middle of March showed a very great decrease in the number of individuals of this species; otherwise the Plankton remains very much the same, the two filamentous Diatoms still preponderating over the others. At the same time Synedra Acus , var. delicatissima is present in sensible numbers (cf. foot-note, p. 637). In May there is no trace of Asterionella , whilst Melosira varians is present in extreme abundance, large numbers of the chains of this Diatom always lying in the field of view under the micro- scope ; Fragilaria is relatively far less abundant. The only other common species is Synedra Ulna , the green forms being just as rare as in March. This latter feature may in part be due to the strong current in the river on this occasion, owing to the heavy rains (cf. p. 631). Samples collected a month later (June 3, 1903) showed an increase in the green forms (species of Pediastrum , Chlamydomonas Braunii, Closterium moniliferum ), whilst the relative number of individuals of Diatoms occurring is approximately the same as before, Melosira varians being by far the most abundant species. In the next month two species of Synedra (S. Uhta and S*. Acus , as well as its var. delicatissima ) develop to an extraordinary extent, Melosira being almost lost in contrast to the numerous needles of these species. Two months before we had a Melosira- Plankton ; in July we have an excellent example of a Synedra-P lank ton. The green forms are now rather abundant, and Synura Volvox is also frequently met with. Stated briefly, the relative development of the Plankton of the Thames at different times of the year is thus as follows : In October, Melosira , Fragilaria , Surirella , &c„ in almost Phytoplankton of the River Thames. 6 37 equal numbers, being accompanied by a development of Asterionella gracillima about the time of the New Y ear ; in May a very abundant development of Melosira varians , succeeded in the summer months again by a great increase in species of Synedra ; in the height of the summer and the autumn con- siderable prevalence of any particular form is not noticeable (according to last year’s results, see Fritsch, ’ 02 ). This periodicity in the course of a year may be summarized thus : — mixed Plankton (with Asterionella~pha.se) — > Melosira-^- Synedra — > mixed Plankton. Asterionella , it should be observed, cannot be said to in- dividualize the Plankton to the extent that Melosira and Synedra do in later months. In the past season, at least, it merely formed a minor phase in the development of the river’s Plankton, and the characteristic outward form of this species alone makes its occurrence so striking and readily noticeable ; there are probably a number of such minor phases \ which are not great enough to give a definite stamp to the Plankton, and most of which would be overlooked in the course of a single year’s observations (cf. also p. 631). If we compare the periodicity of the Plankton of the Thames with that of the Oder and Danube, which was mentioned above, it will at once be perceived that, although we have the same dominant forms, their distribution in the different seasons of the year is not at all identical. Synedra , which is a spring and autumn form in the two continental rivers, attains its maximum during the summer in the waters of the Thames ; whilst Asterionella , which plays some part in the winter- Plankton of the latter, abounds in the Oder and Danube during the summer months, a time at which it is not at all or scarcely represented in the Thames. According to Brunn- thaler, Melosira (but together with Fragilaria) abounds in the Danube in spring, that is to say, at the same time as it does in the Thames ; apparently this Diatom does not occur 1 The relative abundance of Synedra Acus, var. delicatissima in March may possibly turn out to be another such minor phase. 638 Fritsch, — Further Observations on the to such an extent as to characterize the Plankton of the Oder at any particular period. Melosira , being well provided with chloroplasts, would be likely to be able to assimilate freely before forms like Synedra , Fragilaria , &c., with far smaller chloroplasts, were capable of doing so, and its great develop- ment during the spring months may be explained on these grounds (cf. Zacharias, ’99, p. 27). To some extent Asterio- nella and Synedra may be said to have exchanged places in the Thames Plankton with regard to that of the continental rivers. It remains to be seen whether other European rivers show the same periodicity as the Oder and Danube, and whether other British rivers will follow the lines of the Thames Plankton. Our present scanty knowledge of the conditions of life of the Plankton of rivers makes it impossible to account for this divergence ; it may be that the difference of climate, already referred to above, has something to do with the matter. It does not seem likely that the height of the water at some times during this year will have had any effect on the general features of the periodicity of the Plankton, although the minor points may have been to some extent obscured. From what I have seen I do not consider it impossible that different portions of the river’s course, sufficiently distant from one another, may show variations in the periodicity of the Plankton, a point which I hope to examine more carefully next year. A few points regarding the Plankton of this part of the river still deserve mention. In addition to collecting samples from the main river, on several occasions some were also taken from a side-arm of the river between Tatham’s Island and the Middlesex bank. Those taken from this arm in last October contained a number of individuals oiBacillariaparadoxa, Gmel., in a healthy condition, the concertina-like movement of the individuals of the colony taking place in rapid succession. This was not the only marine form observed here at the time, Pleurosigma Fasciola (Ehrb.), Sm. and Navicula amphisbaena , Bory being also represented in small numbers. The peculiar point about their occurrence here is that a diligent search did Phytoplankton of the River Thames. 639 not reveal them in the main river itself, although Bacillaria was found in samples taken from below the lock at Tedding- ton. Possibly the salinity of the water in the shallow arm is greater than in the main river, although Pleurosigma Fasciola was observed in a sample taken from the latter at a later date. The first two of the above-named Diatoms have also been observed by Zacharias (’98, p. 44) in the Unter-Eider (near Rendsburg), the waters of which at this point are of a brackish nature. I have never met with Bacillaria before or after in the river. Stephanodiscus Hantzschianus , a common con- stituent of the Plankton in the warmer months and in the autumn, was frequently observed to be provided with numer- ous elongated needle-like processes at its margin ; such have been already described and figured by Schroder (’97, p. 488 and PI. XXV, Fig. 1), although in the cases observed by me they were relatively far more numerous than Schroder’s figures indicate. They undoubtedly serve to heighten the floating capacity of the individual. The individuals of Nitz- schia sigmoidea , which were very common in some samples, were frequently covered by large numbers of epiphytic speci- mens of Amphora minutissima, whose occurrence in the Plankton is thus due to its attachment to a larger form. Finally the occurrence of Goniuni pectorale in the samples of June 30 is noticeable, it not having been observed in the river before this. In the following portion of this paper I propose to give an account of the flora of some of the backwaters of the Thames between Chertsey and Teddington, of which on the whole there is a remarkably small number. I have already previously pointed out (Fritsch, ’02, p. 578), that the Plankton such as we find it in the main stream, although capable of a certain amount of multiplication, must to a great extent be stocked from other places, namely from the back- waters and slow-flowing tributaries of the river’s course. The presence of these backwaters is of immense importance from the point of view of the fisheries, for it is on the Plankton that the smaller fish, which furnish the food for the larger 640 Fritsch. — Further Observations on the ones, must rely for sustenance. Zimmer (’ 99 , p. 7) remarks as follows on this important subject : ‘ Die verschwindende Planktonmenge eines Flusses kann als Fischnahrung ganz und gar nicht in Betracht kommen. Die Fische, die auf das Plankton des Gewassers als Nahrung angewiesen sind, also namentlich die junge Brut, wiirden in fliessendem Wasser einfach verhungern, sie mussen sich ihre Nahrung da suchen, wo sie zahlreicher vorhanden ist, d. h. einmal in den Stellen zwischen den Buhnen und dann in den Altwassern und den stromlosen Uferbuchten. Da aber zwischen den Buhnen das Plankton quantitativ immer noch ausserordentlich sparlich auftritt, so konnen diese Stellen die Altwasser durchaus nicht ersetzen.’ This sufficiently indicates the value of the back- waters of a river in relation to the production of fish in the same, and the importance of leaving them undisturbed in their natural condition cannot be sufficiently emphasized. The quantity of individuals in the Plankton of a backwater is in most cases very much greater than that in the main stream, although the number of different species is often less (cf. also Fritsch, ’ 02 , p. 584). (i) Backwater just below Molesey Lock (June 3, 1903). Head of backwater. Mouth of backwater. Main river just outside backwater. Melosira moniliformis (Miill.), Ag. . rc. rc. rr. „ varians , Ag c. C. a. Campy lodiscus noricus , Ehrb. . . rr. rr. rr. Surirella biseriata, Breb rr. rc. rc. ,, ovalis , Breb rc. r. r. ,, splendida (Ehrb.), Ktz. . . rc. rc. rc. Cymatopleura Solea (Breb.), Sm. . — r. rr. Amphora ovalis, Ktz. ...... — — rr. Fragilaria virescens , Ralfs .... — — rc. Synedra Ulna, Ehrb — rc. c. Nitzschia sigmoidea (Nitzsch), Sm. . rc. rc. rc. Pleurosigma attenuatum (Ktz.), Sm. . — rc. rc. Tabellaria fenestrata , Ktz. .... r. r. r. Scenedesmus acntus, Meyen. . . . rr. rc. — Pediastrum Boryanum (Turp.), Men. r. r. rc. ,, pertusnm , Ktz rc. rc. rc. Chlamydomonas Braunii, Gorosch. . rc. rc. rc. Eudorina elegans, Ehrb rc. rc. rr. Closterium acerosum (Schrank), Ehrb. rc. rc. — „ moniliferum (Bory), Ehrb. r. r. rc. Phytoplankton of the River Thames . 641 This backwater has a winding course, and penetrates between 1 00-150 yards into the land up to Hampton Court railway station ; it is deep enough to admit of rowing along its entire length. The banks are fairly thickly wooded, pollard willows being especially common. This is the only case I have as yet observed, in which the Plankton of a backwater is relatively poor as compared with that of the main river 1 , although the percentage of green forms present in the former is even here greater. To some extent also there is a difference in the constitution of the Plankton of the backwater and the main stream ; Synedra Ulna , which is common in the latter at this time of the year, is entirely wanting in the backwater, as is also the case with Fragilaria virescens and Pleurosigma attenuation ; on the other hand Scenedesmus acutus and Closterium acerosum were both only found in the backwater, whilst the other species of Closterium is far commoner in the main river. Animals are also considerably more abundant in the backwater. As far as I am aware, the River Mole is in some way connected with this backwater ; and the Plankton of the former, except for the occurrence of a number of blue- green forms (. Microcystis marginata, Merismopedia glaucd), is quite identical with that of the backwater just discussed, being rich in green forms and poor in Diatoms relative to the main river. (ii) Backwater near Sunbury (May 23, 1903). This backwater, except in quantity of individuals, differs very slightly from the main river. It is very shallow, and communicates with the stream by means of a short arm about halfway along its length. At this time of the year there is little vegetation in it ; Nymphaea is just commencing to appear. It has a rich Diatom flora, green forms in corre- spondence with the time of the year being rare. Amongst the Diatoms Pleurosigma Fasciola and Asterionella gracillima 1 Bacteria were rather abundant in some parts of this backwater, which seems to indicate that refuse of some kind has access to it. This may possibly account for the paucity of its Plankton. 642 Fritsch . — Further Observations on the were observed in very small numbers. On the same day a slow-flowing arm a little further down the river was exam- ined ; here the green forms were rather more abundant, and in correspondence with this animal life more frequent than in the main stream. Asterionella gracillima was again observed here, and even in rather greater quantity than in the backwater; it would thus appear as though some of the forms, which are already wanting in the main stream, manage to maintain their existence for a somewhat longer period in some of the backwaters and slow-flowing arms on the river’s course (cf. also the small backwater at Walton, discussed below). The two backwaters at Walton, except perhaps for the one at Shepperton, are the most typical of those examined this year. The first (the ‘ Sale ’) is a broad pond-like arm of the river just below the bridge at Walton; its connexion with the main river is about 5 to 6 yards in breadth, but a very little way inside it broadens out very considerably. It is deep enough to allow of easy rowing, and in part was filled with a growth of Nymphaea , & c. In no part of the river was such a diversity of green forms and Flagellates found as here, whilst blue-green forms, curiously enough, were entirely want- ing. It is unnecessary to especially mention any of these forms, as they are sufficiently evident from a glance at the following table ; the latter also shows how the large majority of them are wanting in the main river. In the case of a form like Synura Volvox , which is abundant in the backwater, the entire absence in the river itself is very noteworthy. On the other hand Gonium pectoral e, which is occasionally met with in the river at this point, was not observed in the back- water. In this latter, however, the first member of Peridineae that I have as yet found in the Thames was observed, but even then only scanty in number of individuals. With regard to the Diatoms, Melosira and the two species of Synedra are represented in rather equal numbers, whereas the latter are the prevalent forms in the river outside. The almost entire absence of Campylodiscus noricus and the species of Surirella Phytoplankton of the River Thames. 643 in the backwater, as contrasted with their occurrence in the main river, is also of interest. A little below Walton Bridge on the opposite (Middlesex) side of the river there is a short, very narrow backwater, which, perhaps owing to its origin in a small bay, formed (iii) Backwaters at Walton (July 1, 1903). The ‘ Sale ’ at Walton Bridge ; t = 23 °C. Backwater a little lower down; t = 2i- 5 °C. Main river at Walton ; t = 2i-5°C. Stephanodiscus Hantzschianus, Grun. . . . rc. rc. rc. Melosira moniliformis (Mull.), Ag r. — r. „ varians , Ag c. a. rc. Campy lodiscus noricus , Ehrb — — r. Surirella biseriata , Br^b — — r. „ ovalis, Breb — r. rr. „ splendida , Ehrb r. — rr. Cymbella gastroides , Ktz — — Fragilaria virescens, Ralfs rc. c. rr. Synedra Acus , Ktz rc. rc. c. „ Ulna , Ehrb rc. rc. c. Nitzschia sigmoidea (Nitzsch), Sm r. — — Pleurosigma attenuatum (Ktz.), Sm. . . . vr. — vr. Pleurostaurum acutum (Sm.), Rabenh. . . rc. — — Scenedesmus quadricauda (Turp.), Br^b. . . rr. — r. ,, acutus, Meyen r. — vr. Pediastrum Boryanum (Turp.), Men. . . . rr. — r. ,, pertusum , Ktz rc. r. rc. ,, pertusum, var. clathratum, Braun rc. r. rc. Eudorina elegans, Ehrb rc. — — Gonium pectorale , Mull — r. r. Pandorina morum , Ehrb rc. r. r. Richteriella polychaete , Fritsch. n. sp. 1 . . . r. — — Closterium moniliferum (Bory), Ehrb. r. — — „ Cornu , Ehrb r. — „ acerosu?n (Schranck), Ehrenbg. vr. — — Staurastrum paradox urn, Meyen rr. — — Ceratium cornutmn , Clap, et Lachm. . . vr. — — Synura Volvox , Ehrb c. r. — Dinobryon sertularia , Ehrb rc. — — Phacus longicaudus , Dujard r. — ■ — 1 This new species is very closely related to Richteriella botryoides, Lemm., the only well-marked difference lying in the occurrence of numerous hyaline processes on each cell of the colony ; further investigation may show such differences to only warrant the establishment of a variety. Figures and full description will be given in a later publication. 644 Fritsch . — Further Observations on the by the river, and its consequent removal from the current, showed a well-marked Plankton of its own. This is chiefly interesting because of the abundance of Melosira varians present, which is quite the most prominent form ; this back- water as it were is at present in the phase of Plankton-develop- ment, found in the main river about two months ago. The Metosira completely eclipses the species of Synedra in num- bers, whilst it is accompanied by a relatively abundant development of Fragilaria virescens. Green forms are rare here, some of them not being even as common as in the main river. The main mass of the Plankton of this backwater is thus constituted by Diatoms. (iv) Backzvater just above Shepperton (June 6, 1903). 1 Backwater ; t = i8°C. Main river; t = i8°C. Stephanodiscus Hantzschianus , Grun. . rc. rc. Melosira moniliformis (Mull.) , Ag. . . — rc. „ varians, Ag a. c. Campy lodiscus noricus, Ehrb — rr. Surirella biseriata, Breb — r. ,, ovalis , Breb . — r. „ splendida (Ehrb.), Ktz. . . . rr. rc. Cymatopleura Solea (Breb.), Sm. . . . IT. r. Cymbella gastroides , Ktz r. — Amphora ovalis , Ktz r. r. Fragilaria virescens , Ralfs a. c. Synedra Acus, Ktz rr. rc. ,, Ulna , Ehrb rr. rr. Nitzschia sigmoidea (Nitzsch), Sm. . . c. r. Pleurosigma attenuatum (Ktz.), Sm. r. rr. j Tabellaria Jlocculosa , Ktz l'C. — ,, fenestrata , Ktz. ..... r. r. Scenedesmus quadricauda (Turp.), Breb. r. r. ,, aculus, Meyen r. — Pediastrum Boryanum (Turp.), Men. . rr. r. „ pertusum , Ktz rc. rc. Eudorina elegans , Ehrb rc. — Pandorina morum , Ehrb rc. — Richteriella polychaete, Fritsch, n. sp. . rr. — Closterium moniliferum (Bory), Ehrb. . vr. ~ Synura Volvox , Ehrb rc. ■ — This backwater is of no very great length, and is sufficiently deep to admit of rowing all along it. The flora shows well- Phytoplankton of the River Thames. 645 marked differences from the main river outside ; the Plankton in the first place is very much richer in number of individuals. The Diatom flora is mainly composed of Melosira varians and Fragilaria virescens , the latter species especially being far commoner here than in the main river. Further, the Plankton of the backwater is characterized by the occurrence of large numbers of splendid specimens of Nitzschia sigmoidea (frequently bearing Amphora minutissima ), which are almost absent from the river itself at this point. Green forms were better represented in the backwater, whilst a number of them (notably Pandorina moram and Eudorina elegans) were entirely wanting in the Plankton of the river ; however, the relative abundance of the green forms with regard to the main river is not so noticeable in this as in some of the other backwaters. It is the Diatom-flora here, as in the case of the smaller backwater at Walton, that affords the characteristic feature. The Plankton of the Wey, which was cursorily examined on this occasion, does not differ noticeably from that of the Thames at this point, except for a rather frequent occurrence of Closterium acerosmn. The most important features of the backwaters are thus : — (i) Relative abundance of the Plankton in individuals as compared with that of the main stream. (ii) Relative greater development of green and blue-green Algae and of the fauna, compared with the river itself. (iii) An often very noticeable difference in the entire specific constitution of the Plankton. On the whole, though however much the Plankton of the backwaters examined may differ from that of the actual Thames, its nature is still very different from that of the Plankton of a pond, and, so to say, always bears the stamp of a river Plankton. As an example, the results of some dredging carried out on the Brentford Reservoir near Hendon towards the end of October of last year may be mentioned. The chief mass of the Plankton consisted of animals, whilst Diatoms were only represented by a species of Stephanodiscus and a few isolated individuals of Surirella ovalis. A con- 646 Fritsch. — Further Observations on the siderable number of other Algae are common, however, Clathrocystis aeruginosa being most abundant. The following other forms were observed : — Pediastrum Boryanum , P. pertu- sum , Scenedesmus quadricauda , wS. acutus with vars. obliquus and dimorphus , Chlamydomonas Braunii , Lemmermannia emarginata , Closterium gracile , £ 7 . striolatum , Staurastrum paradoxum , Gomphosphaeria aponina , Phacus longicauda. — It seems probable, however, that longer backwaters may at their head show less of the character of a river Plankton than those discussed in the present paper ; the backwater at Molesey (see table, p. 640) even showed a greater contrast from the river in the Plankton from its head as compared with that from its mouth. The following are the main points brought out by the present paper : — (i) The Thames has a well-marked living Plankton all the year round. (ii) The periodicity of the Plankton (mixed Plankton — Melosira — Synedra — mixed Plankton) differs rather markedly from that observed in continental rivers ; Asterionella forms a minor phase during the winter months. (iii) The backwaters, although differing very markedly in quality and quantity of the Plankton from the river itself, always bear the stamp of a river Plankton. It is hoped during the next year to make a more complete study of the periodicity and also of the Plankton of the back- waters of the higher parts of the river’s course. University College, London July 6, 1903. Phytoplankton of the River Thames . 647 Literature cited. Brunnthaler (’00) : Plankton-Studien, I. Das Phytoplankton des Donanstromes bei Wien. Verhandl. d. k. k. zoolog.-botan. Gesellsch. in Wien, pp. 308-11. Fritsch (’02) : Algological Notes : III. Preliminary Report on the Phytoplankton of the Thames. Annals of Botany, vol. xvi, no. lxiii, Sept., 1902. Schroder (’98) : Planktologische Mitteilungen : Biolog. Centralbl.,Bd. xviii, no. xiv, 1898, pp. 525-35. (’99) : Das pflanzliche Plankton derOder : Ploner Forschungsberichte, Teil vii, 1899, pp. 16-24. Zacharias (’98) : Das Potamoplankton : Zoolog. Anzeiger, no. 550, 1898, pp. 42-8. (’99) : Ueber die Ursache der Verschiedenheit des Winterplanktons in grossen u. kleinen Seen : Zoolog. Anzeiger, Bd. xxii, nos. 577 and 578. Zimmer (’99) : Das tierische Plankton der Oder : Ploner Forschungsberichte, Teil vii, 1899, pp. 1-15. Zykoff (’02) : Das pflanzliche Plankton der Volga bei Saratow : Biol. Centralbl., Bd. xxii, no. 2, 1902. Yy Two Fungi, parasitic on species of Toly- pothrix (Resticularia nodosa, Dang, and R. Boodlei, n. sp.). BY F. E. FRITSCH, B.Sc., Ph.D., F.L.S. Demonstrator in Botany , University College, London . With Plate XXIX. HE researches of the last twenty years have shown that 1 there are a considerable number of Fungi which infest algal hosts and generally cause considerable havoc amongst them. Lemmermann (’01) has recently enumerated 193 such forms, which belong chiefly to the Chytridineae and the Ancylistaceae. With a member of this latter order we are concerned in the present paper. The genus Resticularia was first established by Dangeard in 1890 for a Fungus, parasitic in Lyngbya aestuarii. Since that time no further contribution towards our knowledge of the genus has, as far as I am aware, been published. Dan- geard’s genus has been accepted by Fischer (’ 92 , p. 84) and by Schroter (’ 93 , p. 92), both authors placing it next to the genus Ancylistes of Pfitzer. Dangeard’s Resticularia nodosa (Dangeard, ’ 90 ) assumes the form of a straight tube, which is frequently appreciably enlarged within each cell of the Alga, so that in its entirety [Annals of Botany, Vol. XVII. No. LXVIII. September, 1903.] Y y 2 650 Fritsch . — Two Fungi , parasitic the parasitic mycelium presents a moniliform appearance. The mycelium, although as a rule simple, is occasionally somewhat branched ; and by means of such branches, emerging from the algal threads into the surrounding medium, infection from one filament to another readily takes place \ Occasionally uniciliate zoospores of relatively large size and moving actively are produced ; these ultimately come to rest on the Alga and germinate immediately. According to Dangeard’s view, a sexual process also takes place, leading to the formation of thick-walled zygospores, which are generally spherical but sometimes elongate-elliptical in shape, and which are often formed in considerable numbers in the same algal filament The germination of these zygospores was not observed. I have observed a species, which is probably identical with the Resticularia nodosa of Dangeard, although differing in a number of points from the author’s original description. Further, a new species from the Pen Ponds, Richmond Park, will be described, which I have great pleasure in naming after its collector, Mr. L. A. Boodle, F.L.S. 1. Resticularia nodosa, Dangeard (?). This Fungus was first observed in a species of Tolypothrix , growing on rocks in the Nepenthes - house at Kew, in October of last year. At this time many of the filaments of the Alga were infested by the parasite (Figs. 19-23). The latter formed long chains of cells within its host, each link of the chain generally occupying one of the algal cells. The successive cells in the chain were separated from one another by true transverse walls, which seem, however, to arise after the con- striction of the fungal hypha has taken place. The shape of the cells of the parasite is very varied, and it appears more or less to adapt itself to the size of the surrounding algal cell. Usually each segment of the Fungus has an elongated elliptical outline (Figs. 19-21), frequently with one or both ends con- siderably dilated ; the cells may, however, also be oval or 1 Dangeard does not figure any such infection. on species of Tolypothrix. 651 almost spherical (Fig. 2,6). Usually the constrictions, and therefore also the transverse walls of the Fungus correspond in position with the dividing septa of the algal filament ; this is due to the narrowing down of the fungal hypha, when it has to pass through a wall of the Alga. Not infrequently the Fungus branches within the host (Figs. 24, 25) and a very complicated tangle may sometimes be formed in this way (Fig. 26). The contents of the fungal segments are colourless, and con- sist of vacuolar protoplasm with one or more bright granules of some oily substance. I Was not able to make out nuclei. The effect on the cell-contents of the Alga was in the first place decolourizing. It would appear that the action of the Fungus does away with the special colouring-matter of the Tolypotkrix-ceUs, so that those which have been recently attacked have a dirty yellowish-green colour. But even this soon disappears, and ultimately the entire cell-contents, as well as the dividing-walls of the Alga, are dissolved away. In the earlier stages of this process the contracted protoplasm forms a kind of granular sack round the fungal cell (Figs. 19, 20). The most striking point about this Fungus, and a point in which it differs from the species to be described below, is the frequent occurrence of thick-walled dark brown cells in the course of the parasitic hyphae ; such cells are to be seen in all my figures of this species. These spores were formed in considerable numbers in the course of each hypha ; they were most commonly single (Figs. 21, 24), often in twos (Figs. 22, 23), and sometimes aggregated together in large numbers. Apparently any cell of the Fungus could develop into one of these spores, but there seemed a great tendency for their formation inside the heterocysts of the Alga (Fig. 20), prob- ably because the conditions of nourishment are worse there than in the other cells of the filament. The heterocysts present a considerable obstruction to the passage of the Fungus, and in many cases the latter was observed to ter- minate at these points (Fig. 19) ; sometimes these terminations 652 Fritsch. — Two Fungi , parasitic were marked by the formation of a group of the thick-walled spores, abutting directly on the heterocyst. These spores arise in the following way : a single segment of the Fungus increases somewhat in size and acquires a thicker wall. This is followed by the appearance of one or two large oily granules in its homogeneous contents (Fig. 27). Ultimately the wall differentiates into two layers and acquires a dark brown colour, and the number of oily granules present generally increases (Figs. 20, 26). The spores have very much the same shape as the fungal segment, from which they arise ; generally a slight rounding-off takes place in their formation. These thick-walled cells are of the nature of chlamydospores ; ultimately the remainder of the Fungus disappears and they alone remain, lying within the empty algal sheath (Fig. 22). They probably undergo a long period of quiescence before germination takes place. Occasionally hyphae are formed as branches on the parasitic mycelium, which emerge from the Alga into the surrounding medium (Fig. 25). They are generally very delicate and show no trace of septation, although drops of oily matter, which to some extent simulate partition-walls, frequently occur in their course. I have no doubt that they serve to infect other (healthy) algal filaments, although I have been unable to obtain figures of such cases. Except for the absence of zoospore-formation, the Fungus I have just described is in most essentials similar to the Resticularia nodosa of Dangeard. The latter observer con- siders the thick-walled spores 1 to have arisen by a sexual process ; he remarks (Dangeard, ’ 90 , p. 98) : ‘ La reproduction sexuelle se fait de la maniere suivante : sur le trajet d’un meme filament le protoplasma se condense par place comme le montrent les figures 29 et 30 ; on ne saurait faire aucune distinction entre le protoplasma male et le protoplasma fe- melle, bien qu’il y ait souvent l’une des portions un peu plus grosse que la seconde ; le filament mycelien sur lequel se forment ces zygospores ne parait pas se cloisonner ; du moins, 1 Dangeard does not remark that the walls of the spores take on a brown colour. on species of Tolypothrix. 653 nous n’avons jamais reussi a voir une cloison quelconque V Dangeard’s figures 129 and 30 give no indication of a fusion between protoplasmic masses or nuclei in the formation of the spores (with the possible exception of Fig. 30), nor does he state that he has seen anything of the kind. His assump- tion that they are sexually-formed zygospores is based on a comparison with Maxime Cornu’s and with Zopf’s figures of Myzocytium and Lagenidium respectively; and he adds that ‘ nous devons noter toutefois que la differentiation sexuelle est bien faible et que, dans beaucoup de cas, il devient impos- sible de la saisir ’ (loc. cit., p. 99). Fischer (’ 92 , p. 85) remarks that, according to Dangeard’s description, ‘ die Sexualorgane in der Weise entstehen, dass in einem aufgeschwollenen Fadenstiick das Protoplasma sich in zwei gleiche Theile verdichtet, die mit einander verschmelzen und die Dauerspore (Zygospore) erzeugen.’ Dangeard says nothing about a fusion, although, by his calling the thick- walled cells zygospores, he tacitly assumes its occurrence. I can see no reason for regarding these spores as having been sexually produced. They are merely formed by an increase in size of a part of the ordinary mycelium, and the fact of their sometimes being formed in groups of three, four or five together alone speaks against their sexual origin ; for there are no traces of empty antheridial cells between the individual spores in such cases. It is true that the young stages often have a sort of pear-shaped form, so that there are apparently a large and a small swelling side by side (cp. Fig. 18 of R. Boodlei ) ; but in these cases the fully-developed spore has the same shape (Figs. 20, 21), and I was unable to detect a differentiation into two protoplasmic masses in the earlier stages. There is one further point, which I think speaks very strongly against the sexual origin of these spores. I have already mentioned that some branches of the parasitic hyphae 1 It is not quite plain to me, whether Dangeard is referring to the entire hypha, in whose course the spore is formed, or to the non-occurrence of a division-wall between the assumed sexual organs ; if the former is the case, this is a point of difference between R. nodosa and the form I am describing. 654 Fritsch. — ■ Two Fungi , parasitic can leave the host and emerge into the surrounding medium. In some cases this external mycelium becomes very much branched, and spores, in all respects similar to those formed on the internal hyphae, are developed on it by a kind of budding-process. Short lateral branches of the unseptate mycelium swell up apically, thus becoming capitate (Fig. 27). In these swellings, as they increase in size, large oily granules appear, whilst the thickened membrane finally becomes dif- ferentiated into two layers and takes on a dark brown colour ; the fully-developed chlamydospore is separated by a trans- verse wall from the mycelium on which it is borne (Fig. 28). The spores, formed in this way, are usually absolutely spheri- cal and are attached by a short stalk— the unaltered portion of the lateral branch — to the mycelium. Such spores were formed in great numbers during the previous month ; un- doubtedly they go through a resting-period, but of what duration I am unable at present to say. A comparison of the figures will show that these spores differ in no respect from those formed internally, and here it is certainly impos- sible to assume the occurrence of a sexual process. Although I have at present preferred not to give the Fungus just described a new name, it may turn out to be specifically distinct from R. nodosa, Dangeard. In this latter species branching is scarce, the spores contain a single large oil granule 1 and are apparently only formed singly, and zoospore-formation is apparently common. The dimensions of the spores agree fairly well. I give the following measurements of the Fungus described : Diameter of internal (parasitic) mycelium = *004—006 mm. „ „ external mycelium = *0005—001 mm. „ „ chlamydospores = *006—009 mm. 2. Resticularia Boodlei, NOV. SP. This species was found parasitic in the filaments of a Tolypothrix , which formed the most characteristic feature 1 Dangeard found that the spores of R. nodosa later came to contain a number of oily granules (loc. cit., p. 98) ; he interprets this as a stage preceding germination. 655 on species of Tolypothrix. of the algal vegetation in the lower of the two Pen Ponds, Richmond Park, last November ; since then the Alga has practically disappeared. In the material collected in November, 1902, all the algal filaments presented a healthy appearance, and the only indi- cation of the presence of the Fungus was to be found in the occurrence of numbers of colourless spores of relatively large size between the threads of the Tolypothrix . These spores had rather thin walls generally differentiated into two layers, and possessed clear, homogeneous contents (Fig. 1) ; many of them had grown out at one or more points, giving rise to unseptate hyphae, which frequently followed the course of the algal filaments externally, not rarely enveloping them in a perfect mycelial web, which, however, remained purely epi- phytic. In germination the external layer of the membrane is ruptured, and the contents surrounded by the internal layer grow out. One curious feature observed at this date remains to be mentioned. Some of the spores appeared to lie within the external layer of the Tolypothrix- sheath, a position for which I am unable to account (Fig. 1). In samples of the same Alga, collected a month later, it was at once apparent that some change had taken place. In many places the dark green colour of the Tolypothrix had given way to a dirty greenish-yellow, and all transitions between these two colours could be observed with the naked eye. A microscopic examination showed that now, in addition to the abundant epiphytic mycelium of the Fungus, large numbers of hyphae had penetrated into the interior of the Alga 1 ; Fig. 2 shows a germinating spore, the hypha from which has pierced the sheath and grown for a short distance inside the host. Once successfully inside, the Fungus makes rapid progress, and large numbers of the algal filaments were found to contain long moniliform hyphae, like the one shown 1 It is curious that a diligent search revealed no traces of parasitic hyphae a month before. Possibly the Fungus is only able to penetrate into the Alga, when the latter is in a low state of vitality. The way in which the filaments of the latter are enveloped by the epiphytic mycelium might alone tend to produce such a state ; and thus ultimately make it possible for some hyphae to penetrate into the host. 656 Fritsck.—Two Fungi , parasitic in Fig. 3. This moniliform shape of the parasitic hypha is due to the same cause as in R. nodosa , Dangeard ; that is to say, the Fungus expands considerably within each cell of the Alga, narrowing down each time it has to penetrate one of the transverse walls of the latter. The Fungus itself at this stage either presents no partition-walls whatever, or they only occur at very rare intervals ; this is readily discerned with a high power of the microscope. As the parasite grows on in front, it generally dies off behind, and* the posterior portion is then cut off from the living anterior part by the successive formation of transverse walls ; these generally arise at the points where the constrictions occur (Figs. 8, 10). The living portion of the Fungus has perfectly homogeneous contents of an opaque white appearance, occasionally inter- rupted by small drops of oily matter of a highly refractive nature (Figs. 3, 7). Nuclei were not observed. The segments are most commonly ovate, but occasionally spherical. The Fungus only rarely pursues a straight course within the Alga ; generally it is more or less zigzag or spiral 1 . The Fungus has the same effect on the cell-contents of the Alga as the species first described ; in both cases no deforma- tion of the algal filaments, such as Dangeard describes as occasionally occurring in the Lyngbya attacked by R. nodosa (cp. Dangeard, ’ 90 , p. 96), was observed. Fig. 3 shows the protoplasmic contents of the algal cell contracted around the segments of the parasite, whilst Figs. 4, 7, 8, &c., show stages in which the Fungus alone remains within the sheath of the Tolypothrix. Usually only a single fungal hypha is to be seen in each algal filament ; in a very few cases branching was observed to take place, both branches continuing to live inside the host. On the other hand, external branches, i. e. branches which penetrate the sheath of the Alga and emerge into the surround- ing water, are very common. Figs. 3 and 4 show early stages in the development of such branches, whilst Figs. 5, 6 , and 7 1 In passing from one homogonium of the Alga to another the hypha narrows down and presents no constrictions (Fig. 8) ; cp. also Dangeard, loc. cit., p. 97. on species of Tolypothrix . 657 show them in the fully-developed condition. These external branches are generally somewhat narrowed down at the point where they pass through the algal sheath, expanding again as soon as they enter the water. Except for the absence of the regular constrictions, they in every way resemble the internal mycelium ; transverse walls occasionally occur in their course. They are frequently branched and ramify in all directions in the water. The vegetative cells of the internal mycelium, from which they arise, are in no way especially modified. When these hyphae come into contact with another healthy algal filament they frequently penetrate its sheath, and give rise to a parasitic mycelium within (Figs. 10, 11). Such infecting hyphae (‘ Ansteckungshyphen ’) are one of the chief means of propagation of the Fungus, and constitute a strong point of resemblance to the genus Ancylistes , in which they occur abundantly. It should, however, be remarked that these hyphae were often seen to come into contact with a healthy filament of the Alga without attacking it. In some cases the hyphae arising from the parasite all grow out in one and the same direction, as though there were some stimulus regulating their formation and direction of growth. The thick-walled heterocysts of the Alga (which in this species occurred in groups of 4-9 together), again presented a considerable obstruction to the passage of the Fungus, and not rarely seemed to form an unsurpassable barrier. Further, the Alga protects itself by the formation of thick transverse walls some little way in front of the momentary position of the Fungus 1 . Apparently these also form considerable obstacles to the growth of the latter, and in some few cases the Fungus was observed to emerge from the filament at such a point and to come in again on the other side (Figs. 13, 14), finding it easier to pass through the thick sheath than through the protecting wall formed by the Alga. To the difficulty of passing through a heterocyst must also be 1 Such protecting-walls were also, but rarely, seen in the case of the first- described species. 658 Fritsch . — Two Fungi , parasitic attributed the fact that the Fungus so frequently leaves the main filament for a branch at the points, where branching of the Tolypothrix occurs ; it thus avoids the heterocyst, which is situated immediately above the point of branching. A few anomalous cases were observed in connexion with the external mycelium. Thus Fig. 12 shows a hypha which has just emerged and has formed a number of branches, one of which is again penetrating into the same algal filament, whilst Fig. 15 shows a case where the mycelial branch has re-entered the Alga and fused with the hypha from which it arose. I have already mentioned that the external mycelium may be very much branched. In some cases it attains a great development and proceeds to form large numbers of spores. The mycelium then becomes septate and develops numerous lateral branches, which generally do not reach any con- siderable length. In these branches transverse walls are formed, so that they come to consist of a row of thin-walled cells. These increase in size, at the same time assuming an elliptical shape (Fig 16), and develop into the thin- walled spores, which were first seen in November last. In some cases the lateral branches are very short and only develop into a single spore, which is thus formed in a way very similar to the chlamydospores of the first described species. In other cases the mycelium proceeds to form these spores immediately after emerging from the Alga, as is seen in Fig. 17 ; here the entire external mycelium has been trans- formed into spores. This is frequently the case, and when spores are thus formed from a strongly-branched and ex- tensive mycelium we get enormous masses of them, many of which still show their origin from a row of cells. The spores are oval and generally slightly drawn out at one or both ends, owing to their previous position in a moniliform thread (cp. Fig. 16). When occurring in extensive masses the shape of the individual spores is often very curious, probably owing to mutual pressure in their crowded position. These spores can germinate almost at once, sending out one 659 on species of Tolypothrix. or two hyphae in various directions (Figs. 5 and 9), relatively only a few of which are successful in penetrating an algal filament. Fig. 5 shows a spore which has rather thicker walls than is usual in this species ; such spores are occasionally to be found. As already mentioned, this mode of formation of the spores does not account for their occasional position within the layers of the Tolypothrix-shediXh (Fig. 1). Such a position can be accounted for by assuming spore-formation to have taken place on a mycelial branch, ramifying in the sheath of the Alga. Such mycelial branches undoubtedly occur, but I have never observed a formation of spores in them. In a few individuals certain parts of the parasitic hyphae were seen to be very much more swollen than others (Fig. 18); such swollen portions may possibly develop into internal spores, analogous to those of R. nodosa , Dang., but I have as yet been unsuccessful in following up their further fate. They were especially observed in material grown in a solution of cane-sugar. Since the spores usually formed by R. Boodlei are relatively thin-walled and incapable of existing for a long period, it would seem natural that they should only be formed on the external and not on the internal mycelium. For spores, formed in this latter position, must be surrounded for a long time by the empty sheath of the Tolypothrix , and months would ordinarily elapse before this latter would decay and leave the spores lying freely in the water. It is true that the fungal hyphae normally have to penetrate the sheath of the Alga, but it is questionable whether a young, just- formed hypha is capable of doing this. I have had the species described under observation for several months, and have seen no indication of zoospore- formation. The life-cycle of R. Boodlei may be briefly summarized as follows : Mycelial branches, emerging from the internal parasitic hyphae, give rise to large numbers of thin-walled spores. These germinate almost at once, giving rise to one or more hyphae, which attack the host and penetrate into 66o Fritsch.—Two Fungi , parasitic its interior. Branches of the internal mycelium also serve to convey the Fungus from one individual to another. I give the following measurements of this species : — Diameter of the internal mycelium = -005 - -008 mm. „ „ external „ = -0015 - -005 mm. „ „ spores = -oi2 - *015 mm. A few remarks may be added on the bearing of the facts, described in this paper, on the systematic position of the genus Resticularia. As far as I am aware, the formation of spores on external branches of the parasitic mycelium is a feature as yet unobserved in the Ancylistaceae ; and in the two species under consideration this is evidently a common method of propagation. Whereas the species, which I have provisionally united with R. nodosa , Dangeard, forms thick- walled chlamydospores, R. Boodlei has thin-walled spores, incapable of standing a long resting-period. Undoubtedly this latter species also forms chlamydospores of some kind, enabling it to pass through unfavourable external conditions ; and it remains to be seen whether R. nodosa does not also form thin-walled spores at some period in its life-history. Since the observations contained in the preceding pages tend to cast considerable doubt on the sexuality of R. nodosa , one of the chief links connecting the genus in question with Ancylistes is removed. According to Pfitzer’s description (’72, p. 379), there are undoubted dioecious sexual organs in this latter genus. In many respects, however, Ancylistes and Resticularia are similar to one another, and it will be best for the present to leave them side by side ; although further observations may make it advisable to place the latter genus in a separate section of the Ancylistaceae 1 . Renewed observations may 1 Quite recently v. Deckenbach has published an interesting treatise on a new Fungus parasitic in marine species of Calothrix ( Coenomyces consuens , nov. gen. nov. spec., Flora, Bd. xcii, 1903, pp. 253-83, PI. VI and VII), which further contains a lengthy discussion of the phylogenetic relationships of the Fungi. Coenomyces possesses a well-developed septate mycelium, and is propagated by means of uniciliate zoospores (the only method of reproduction observed) ; owing to the occurrence of these two characters side by side, which are considered as on species of Tolypothrix . 66 1 also make it advisable to separate R. Boodlei generically from Dangeard’s species. The following is a brief description of the genus Resticularia and its two species : — Resticularia , Dangeard (emend.). Mycelium in part endophytic, in part ectophytic. Endo- phytic mycelium moniliform, with or without transverse septa, occasionally forming chlamydospores ; ectophytic mycelium with or without septae, generally strongly branched and form- ing thin- or thick-walled spores. Other portions of the ectophytic mycelium act as infecting-hyphae. Sporangia formed in the endophytic mycelium, the contents of which are protruded to the outside through the wall of the host and there split up into a small number of zoospores, the latter rather large and uniciliate. R. nodosa , Dangeard (emend.). Endophytic mycelium (diam. 4 -6 /tx) usually septate, and forming numerous chlamydospores (diam. 6- 9 /x), ectophytic mycelium very fine (diam. *5-1 /x), much branched, forming numerous chlamydospores, singly on lateral branches. In- fecting-hyphae rare. Endophytic mycelium commonly branched. Zoospores occasionally formed. In the filaments of Lyngbya aestuarii (Dangeard !) and Tolypothrix sp. (mihi !). R. Boodlei , Fritsch, n. sp. Endophytic mycelium (diam. 5-8 /x), with occasional septa ; ectophytic mycelium relatively broad (diam. 1*5-5 /*)> much characteristic of the higher and lower Fungi respectively, a new division, Coenomy- cetes, is established for the reception of the genus Coenomyces , and to this Aphanistis must probably also be referred. This division is thought to occupy an inter- mediate position between Phycomycetes and Eumycetes, although originating from an independent stock. The space at my disposal does not allow of a detailed discussion of these views, but the existence or non-existence of transverse walls in a fungal mycelium does not appeal to me as a point of great importance. In Resticularia nodosa , Dang., for instance, the internal mycelium is distinctly septate, whilst in R. Boodlei septation only occurs in connexion with the dying out of the hyphae ; in this latter species, however, the external mycelium at the time of spore- formation is distinctly septate. I have not yet observed the zoospores of these two species (cf., however, Dangeard for R. nodosa), but their discovery would seem to me to necessitate the inclusion of this genus in the Coenomycetes , if further in- vestigation warrants the maintenance of this group. (Note added July 6, 1903.) 662 Fritsch . — Two Fungi , parasitic branched, forming numerous large thin-walled spores (diam. 12-15^), generally in a chain on lateral branches. Infecting- hyphae abundant. Endophytic mycelium rarely branched. Zoospores not observed. In the filaments of Tolypothrix , sp. It only remains for me to acknowledge the kind assistance of a friend in the preparation of the figures for this paper. University College, London. March 6, 1903. References to Literature. Dangeard (’90) : Recherches histologiques sur les Champignons. Le Botaniste, 2 e ser., 1890-1, pp. 96-9, PI. IV, Figs. 24-31. Fischer (’92) : Rabenhorst’s Kryptogamenflora v. Deutschland, Oesterreich u. der Schweiz. Erster Band, 4. Abtheilung, Phycomycetes, 1892. Lemmermann (’01): Die parasitischen u. saprophytischen Pilze der Algen. Abh. Nat. Ver. Brem., 1901, Bd. xvii, Heft 1, pp. 185-202. Pfitzer (’72) : Ancylistes Closterii , ein Algenparasit aus der Ordnungder Phyco- myceten. Monatsber. der Konigl. Acad. d. Wissensch. zu Berlin, 1872, p. 379. Schroter (’93) : in Engler-Prantl, Natiirl. Pflanzenfam., 1. Teil, 1. Abtheilung, 1893, p. 92. on species of Tolypoihrix. 66 3 DESCRIPTION OF FIGURES IN PLATE XXIX. Illustrating Dr. Fritsch’s paper on Fungi parasitic on Tolypothrix . Figs. 1-18. Resticularia Boodlei , n. sp. Fig. i. Two spores, lying in the membrane of the Tolypothrix , from which epiphytic hyphae have arisen, x 600. Fig. 2. A spore has germinated, giving rise to a short endophytic mycelium, x 600. Fig. 3. Fully-developed parasitic hypha, showing moniliform constrictions ; at a, an external branch is developing, x 750. Fig. 4. The same ; shows a further stage in the development of the external branch, x 750. Fig. 5. A spore has germinated at both ends ; one of the hyphae thus formed has penetrated a filament of the Alga, giving rise to a parasitic, moniliform hypha in both directions. From the internal mycelium an infecting-hypha has branched off. x 750. Fig. 6. A spore has germinated; the parasitic mycelium has formed three infecting-hyphae. x 750. Fig. 7. Oily granules are seen in the mycelium ; also an infecting-hypha. x 750. Fig. 8. The Fungus has died off behind and has become septate in the dead portion ; in front the mycelium is not constricted, but forms a straight tube, x 750. Fig. 9. Spore germinating; the penetrating hypha has spread out in both directions along the algal filament. The latter has formed thick protecting-walls, a little way in front of the present position of the parasite, x 750. Figs. 10, 11. Infection from one individual of the host to another. The dead posterior portion of the parasite has become septate, x 750. Fig. 12. Reinfection of same filament ; see explanation in text, x 750. Figs. 13, 14. Evasion of the protecting-walls formed by the Alga, x 750. Fig. 15. Reinfection and fusion; see explanation in text, x 750. Fig. 16. Formation of spores on the external mycelium, early stages. The arrow indicates the point at which the main hypha continued and joined on to the endophytic mycelium, x 750. Fig. 17. The same; further advanced stage. The entire external mycelium has given rise to spores, x 560. Fig. 18. At sp. internal spores are possibly developing, x 750. Figs. 19-29. Resticularia nodosa , Dangeard (?). Fig. 19. This shows the ordinary appearance of the parasitic mycelium, which terminates at one of the heterocysts of the Alga. The cell-contents of the latter are contracted about the Fungus, x 600. Fig. 20. The same ; a chlamydospore has developed within the heterocyst, x 600. Fig. 21. A chlamydospore is developed in the course of the internal mycelium, x 600. Figs. 22, 23. Show chlamydospores ; in Fig. 22 they alone remain, x 600. Z Z 66 4 Fritsch . — Two Fungi on Tolypothrix . Fig. 24. The internal mycelium branched ; a chlamydospore has been formed on the simple portion, x 600. Fig. 25. Internal mycelium branched; an infecting-hypha has been developed, x 760. Fig. 26. Two chlamydospores are growing out to form long external hyphae. x 750. Fig. 27. Young stages in the formation of external chlamydospores. x 750. Fig. 28. Later stages in chlamydospore-formation. x 750. Fig. 29. An isolated chlamydospore with a portion of the external mycelium, x 760. ^/bznaZs ofHotariy H-L.aiid F.E.F, del. FRITSCH. — FUNGI IN TOLYPOTHRIX. voixvn.pijm. University Press, Oxford. ^/bmals ofHotomy Vo l XVII, PI. XXIX. Hi. and F.E.F, del. FR1TSCH.— FUNGI IN TOLYPOTHRIX. University Press, Oxford. Studies on the Araceae. The Embryo-sac and Embryo of Aglaonema and Spathicarpa. BY DOUGLAS HOUGHTON CAMPBELL, Professor of Botany in the Stanford University , California , U. S.A. With Plates XXX, XXXI, and XXXII. EVERAL years ago a series of investigations were under- O taken upon the development of the embryo-sac and embryo in the Araceae. Some of the results of these studies have already been published 1 , but the investigations were interrupted for a time owing to pressure of other work, and have but recently been resumed. The present paper deals for the most part with two species, Aglaonema commutatnm , Schott, and Spathicarpa sagittaefolia , Schott. The earlier literature upon the development of the Araceae has been referred to in the writer’s previous papers, and will not be repeated here. A paper by Caldwell upon Lemna 2 was omitted, but except for this the writer has seen no further contributions to the subject. The materials upon which the present paper is based were collected at the Royal Botanic Gardens at Kew, in August, 1899. Through the kindness of the director, Sir W. Thiselton- Dyer, it was possible to obtain complete series of a number of species from the rich collection of Aroids in the greenhouses at Kew. Some of the material still remains to be investigated. 1 Annals of Botany, xiv, March, 1900. 2 The Life History of Lemna minor } Bot. Gazette, xxvii, Jan. 1899. [Annals of Botany, Vol. XVII. No. LXVIII. September, 1903.J Z Z % 666 Campbell . — Studies on the A raceae. Nearly all the Araceae that have been studied show certain anomalies in the character of the embryo-sac, and this makes it all the more desirable that further investigations should be made upon this interesting family. Both of the species especially treated in the present paper show more or less marked deviations from the ordinary angiospermous type. It is hoped that further study of other genera of the Araceae may not only add to our knowledge of this family, but may also throw light upon the character and origin of the embryo- sac of the lower Monocotyledons. Among other forms collected in Jamaica in 1897, was a species of Aglaonema , probably A. commutatum , cultivated under the name Dieffenbachia Aglaonema , which showed some puzzling abnormalities ; but the material was too incomplete to make a thorough study of these possible. What was apparently the same thing was found flowering freely at Kew, and a good supply was secured which served for the basis of the work now recorded. Much the same peculiarities of the embryo-sac noted in the Jamaican specimens were found, and a fairly complete study was made of the species. The other form to which special attention has been given was Spathicarpa sagittaefolia , which was flowering and fruiting very freely in the Kew greenhouses. Owing to the large amount of mucilaginous matter secreted by the ovules in many Araceae, they are especially difficult to fix properly, and even with the greatest precautions much of the material was very unsatisfactory. On the whole, the best results were obtained by the use of a concentrated alco- holic solution of corrosive sublimate. Aqueous fixing fluids were useless in most cases. Some good results were also obtained by the use of alcohol, to which ten per cent, of acetic acid was added. This was not specially satisfactory for fixing nuclei, but otherwise often gave very good results. Fleming’s triple stain was used with success in some cases, but very good preparations were also made by staining with alcoholic Bismarck-brown and aniline-safranin. Most of the Araceae that have been examined show various Campbell. — Studies on the Araceae. 667 peculiarities, both in the formation of the endosperm, and in the behaviour of the antipodal cells. Some of them, like Arisaema triphyllum 1 , differ also from the usual angiosper- mous type, in the character of the archesporium. The arche- sporium in this species shows in cross-section from two to four or five cells, which, according to Mottier, are the product of the division of a single primary archesporial cell. It seems probable, however, that sometimes, at least, these cannot all be traced back to the division of a single primary archesporial cell, but arise from two or more independent sub- epidermal cells. A similar archesporium has been found by the writer in Aglaonema commutatum . and it is quite probable that further research will show the same thing in other Araceae. Hofmeister 2 showed that in nearly all the Araceae ex- amined by him the endosperm at an early period fills the embryo-sac with a continuous tissue, or in some cases leaves a greater or smaller portion of the cavity permanently empty 3 . He however misunderstood the process of cell-division by which the endosperm is formed, and supposed that in all cases there was a ‘ free cell-formation 5 preceding the formation of the solid endosperm. It is true that in Pothos longifolia he found frequently an early division by a transverse cell-wall ; but he infers that the subsequent endosperm formation, which he says is confined to the upper and larger of the two primary cells, is formed by ‘ free cell-formation,’ and not by successive cell-divisions, as is probably the case. A type of endosperm formation somewhat similar to that of the Araceae has been described by Strasburger 4 for Ceratophyllum. In this case, however, the first division-wall in the embryo-sac divides it into equal parts. Hofmeister called attention to the large size of the antipodal cells in some species of Arum , and the writer has found in Lysichiton a remarkable development of the antipodal cells 1 Mottier, Bot. Gazette, 1892. 2 Neue Beitrage zur Embryobildung, &c. ; Monocotyledonen. Leipzig, 1861. 3 1. c. p. 704. * Ein Beitrag zur Kenntniss von Ceratophyllum submersum , Pringsheim’s Jahrb. fur wiss. Botanik, xxxvii. 564, 1902. 668 Campbell. — Studies on the Araceae . subsequent to fertilization, and much the same thing occurs in Spathicarpa , and probably in other Araceae as well. On the other hand, in Aglaonema commutation , it was often im- possible to demonstrate certainly the presence of any antipodal cells, although in the apparently closely related species, A. pictum , they seem to be always present. The development of the embryo in the two species under consideration does not show anything specially noteworthy. In Spathicarpa the embryo remains small, and there is a largely developed endosperm in the ripe seed ; in Aglaonema the mature embryo nearly fills the embryo-sac. The very considerable variation shown in the types of Araceae already studied make it highly desirable that as many types as possible should be investigated in order to determine the affinities of the family. It is to be hoped that the characteristic genera of the eastern United States may be examined by some of the botanists who are interested in the morphology of the embryo-sac, and have access to material of our native Araceae. Aglaonema. The genus Aglaonema 1 comprises about ten species of the East Indies and Malayan region. Several species, including A. commutatum , are in cultivation. The latter species was flowering freely at Kew in August, 1899, and apparently the same plant was collected at the Hope Gardens, near Kingston, Jamaica, in the summer of 1 897. A second species, A. pictum , was also flowering at Kew, and material of this species was collected. The flowers are unisexual, the pistillate flowers being borne at the base of the thick spadix, the crowded staminate ones occupying the upper portion. No perianth is developed, but there is a conspicuous white spathe, partially enwrapping the base of the spadix. The pistillate flower consists of a single carpel, with a 1 Engler and Prantl, Die natiirlichen Pflanzenfamilien, n. Th., 3. Abth., p. 135. Campbell. — Studies on the Araceae. 669 large solitary anatropous basal ovule. The nearly globular ovary is crowned with a large discoid sessile stigma, slightly depressed in the centre, where it joins the very short canal leading to the ovarian cavity. While A. commutatum and A. pictum agree closely in their structure, the former, owing to its larger nuclei, as well as from the peculiarities of the embryo-sac, was especially studied, and, unless otherwise stated, the account here 'given refers to this species. The ovule from the first is very massive, and while the integu- ments are developed at an early period, they remain short, the chalazal region of the ovule being very large — a not uncommon feature in other Araceae as well. The short funiculus is also very thick. The nucellus is relatively small. In the youngest stage observed (PI. XXX, Fig. 1) the young embryo-sac was already evident, an elongated cell with a large nucleus. Whether in this case the embryo-sac arose directly from a hypodermal cell, or whether it was the product of the division of a primary archesporial cell, could not be positively ascertained. The lateral tissue of the young nucellus consists of two of three layers of cells, while at the summit the cells are some- what larger, and persist as a cap of tissue after the lateral tissue of the nucellus is destroyed. This occurs at an early stage, so that the embryo-sac soon comes into contact with the inner integument. In a number of cases observed, and this evidently is not unusual, the archesporium consisted of two or three large cells, all of which were apparently potential embryo-sacs. These ovules (Figs. 5, 7) much resemble those of Arisaema triphyllum. As the embryo-sac enlarges the lateral tissue of the nucellus is soon crowded upon, and finally becomes quite obliterated. The apex of the nucellus, as in many other similar cases, persists as a conical cap above the apex of the embryo-sac. There is so much variation in the behaviour of the embryo- sac in its earlier stages that it is difficult to say what may be 6 jo Campbell. — Studies on the Araceae. considered the normal development. No tapetal cells were observed in any case, and the single archesporial cell, or each of the two or three cells where more than one embryo-sac mother-cell is present, develops at once into the embryo-sac. Where two or three young embryo-sacs develop, they may be separated by an obliquely transverse wall (Fig. 7), or more commonly by oblique or longitudinal walls (Fig. 5). Where a single embryo-sac only is present, it enlarges rapidly, and the nucleus divides as usual, the two daughter- nuclei sometimes at least occupying approximately the micro- pylar and antipodal ends of the young sac (Fig. 4). With the crowding upon the nucellar cells, their nuclei become extraordinarily flattened, assuming the form of thin discs, in which the nuclear network is extremely conspicuous (Fig. 4, c). After the second nuclear division in the embryo- sac, the nuclei may be in pairs at the end of the sac, but this is not always the case. In the specimens shown in Fig. 6 the four nuclei were close together at the apex of the sac, and from other cases examined it is clear that the polarity, so marked in the embryo-sac of most Angiosperms, is in this case very slight or quite absent. Even where the nuclei are in two groups they are more often placed laterally than at the extremities of the sac. This is especially true of the group from which the egg-cell develops. So far as could be deter- mined from the examination of a large number of ovules, the characteristic structures of the typical angiospermous embryo- sac, the egg-apparatus, polar nuclei, and antipodals are never clearly differentiated in Aglaonema commutatum. While the number of nuclei is probably eight in most cases, there are frequently deviations from this number. In the specimen shown in Fig. 8, c, d , e , there were twelve nuclei, in three groups of four ; Fig. 18 shows a sac with ten nuclei, six in one group and four in the other ; in Fig. 9 is shown a sac in which the nuclei were only four, although something like an egg-apparatus was evident at the micropylar end of the sac. Where the archesporium consists of more than one cell, Campbell. — Studies on the Araceae. 671 each is a potential embryo-sac, and its nucleus may undergo the first divisions ; but in no case observed was more than one complete embryo-sac seen. The secondary embryo-sac, where two are present, may persist, however, until the defini- tive embryo-sac has reached its full development ; indeed it is quite impossible sometimes to be certain whether the structures present at the time of fertilization are all the products of a single embryo-sac, or of two (see Fig. 11). Where two or three embryo-sac mother-cells are present, they are often quite similar, and as the nucleus may divide once or twice in all of them, it is impossible to determine which is destined to become the definitive embryo-sac. In Fig. 5 is shown an ovule where there are two entirely similar young embryo-sacs, each of which contains four nuclei. In another case observed (Fig. 7) there were three young embryo-sacs separated by oblique walls. In the upper one [a) there was a single large nucleus ; in the second ( b ) there were eight nuclei, in two groups of four, and the members of each group partially fused, in a manner entirely similar to the ordinary fusion of the polar nuclei. The lower sac ( c ) was apparently the definitive embryo-sac. There were eight (possibly nine) nuclei in this. Four of the nuclei w r ere enclosed by delicate membranes, and formed a group of Cells suggesting an egg- apparatus, or possibly a group of antipodal cells. Near these was a nearly hemispherical cell ( o ) whose nucleus was pre- paring to divide. This was near the upper end of the sac, but at one side. Near the base of the sac was a group of large nuclei, partially fused together, and presumably giving rise to the endosperm-nucleus. Three nuclei were very plainly seen, and there was possibly a fourth one, but this could not be certainly determined. Whether the two groups of nuclei in the second embryo-sac (b) were destined to take part in the endosperm formation, could not, of course, be determined. In the embryo-sac shown in Fig. 10 there were eight nuclei. Four of them were at one side of the sac near the apex, and there was some indication of the differentiation of 672 Campbell. — Studies on the Araceae . an egg-cell. The other four were at the antipodal end of the sac, but there were no clearly indicated antipodal cells, nor was there, at this stage, any indication of polar nuclei. A second embryo-sac, containing two nuclei, accompanied this one. Fig. 23, which shows an embryo-sac taken from the Jamaican specimens, differs from any cases found in the material collected at Kew. At the micropylar end of the sac was a well-marked egg-apparatus, consisting of two clearly defined synergidae and an egg-cell. At the chalazal end were two large nuclei surrounded by a mass of granular cytoplasm, and evidently in the early prophases of division. It would certainly seem that in this case no polar nuclei could be developed, and from older specimens from the same plant (Fig. 24) it looks very much as if the basal nuclei assumed at once the role of endosperm nuclei, proper antipodal cells being quite suppressed. The specimen figured as Fig. 18 showed ten nuclei. Four of these were at the base of the sac, where there was developed a group of four cells, one of which projected into the cavity of the sac, and may have been the egg-cell, but it is possible that this group of four cells may have been antipodal cells. Nearly opposite these were six free nuclei, but no further differentiation could be discerned, and what the further history of the sac would have been could only be conjectured. In the embryo-sac shown in Fig. 12 there were twelve nuclei. In this case the pollen-tube could be seen, but it was not certain which were the generative nuclei. Above the sac was a second one, in which were two conspicuous nuclei, which may possibly have been the generative nuclei derived from the pollen-tube, but they were much more probably the nuclei of the second embryo-sac. The apex of the lower embryo-sac contained no nuclei. At the lower end were four nuclei ( b ) with delicate membranes between them, and prob- ably to be considered as antipodal cells. Near them was a second group of four cells, which may have represented the egg— apparatus, and on the opposite side of the sac were four Campbell . — Studies on the Araceae. 673 free nuclei, apparently in process of fusion ( c ), presumably to form the endosperm-nucleus. The specimen drawn in Fig. 13 showed a group of four cells at the apex of the sac. Of these, two lying side by side ( 0 , o') were hemispherical, and probably one of them was the egg. In contact with this group of cells was the enlarged end of the pollen-tube, containing a nucleus, which was probably one of the generative nuclei. The second generative nucleus was not clearly visible. Nothing resembling antipodal cells could be seen, but four free nuclei (Fig. 14) were seen in the cavity of the embryo-sac. Two of these were larger, and in close contact. The other two showed some indications of disorganization. Fig. 15 shows a very peculiar case, which was probably abnormal. There were apparently three embryo-sacs, two smaller ones above and the larger definitive one below. The two upper ones showed signs of degeneration. In the lower one, the chalazal end of the sac was occupied by two very large irregular nuclei (Fig. 16) having every appearance of being composed of several nuclei fused into one. Two other nuclei were present, one of which (Fig. 17) also looked as if it were compound. In Fig. 11 is shown a puzzling case. Separated from a large cell below, were two distinct cells which may have been derived secondarily from a division of the primary embryo- sac, or may perhaps represent two other embryo-sacs. There was no sign of degeneration in these, and with the large lower cell they seemed to form one structure. Traces of the pollen-tube could be seen, and in one of the cells two nuclei could be seen which were possibly the generative nuclei. Besides these nuclei, two others were present, and in the second of the upper cells there were three nuclei. In the lower cell were two large nuclei in close apposition. It is very evident that in Aglaonema commutatum we have to do with an extraordinarily variable plant. The not infre- quent increase in the number of the embryo-sac nuclei, and the imperfect differentiation of the usual structures of the 674 Campbell. — Studies 071 the Araceae. embryo-sac, are worthy of note, as is also the absence of marked polarity in the arrangement of the nuclei. The frequent occurrence of multiple nuclear fusions is also inter- esting, as in this respect this species furnishes a condition intermediate between that found in Peperomia and that occur- ring in the typical Angiosperms. A similar condition has been found to exist also in the peculiar genus Gunner a 1 . Where the egg-cell was evident it was usually hemispherical, and was either at the apex of the sac or, more often, laterally placed. While the pollen-tube was seen in a few cases, the fertilization was not satisfactorily made out, and it is possible that some of the apparently abnormal appearances encountered may have been due to lack of fertilization. The development of the embryo is slow at first, and it remains very small until the endosperm is well advanced in its development. It is not rare to find the embryo-sac filled with a solid mass of endosperm, without any certain evidence of an embryo being present at all. The Endosperm. It is not probable that the formation of the endosperm is entirely uniform in Aglaonema coinmutatum. To judge from the frequency with which multiple fusions of the nuclei of the embryo-sac are encountered, it is likely that in such cases the primary endosperm-nucleus results from such fusions, although it also probably may arise from the fusion of two nuclei, as in most Angiosperms. The definitive endosperm nucleus was not seen, nor was it possible to find the first division : but to judge from a comparison with Spdthicarpa and Anthiirium , in which the young endosperm presents much the same appearance, it is probable that the first division is accompanied by a wall which cuts off a relatively small cell from the base of the embryo-sac. This is followed by a similar division in the cavity of the embryo-sac, and 1 Schnegg, Beitrage zur Kenntniss der Gattung Gunnera, Flora, Bd. 90, pp. 161-208 (1902). 675 Campbell. — Studies on the Araceae. a second cell is cut off from its base, in contact with the first one. In this way the formation of a solid endosperm pro- ceeds from the base upwards (Fig. 21) until the whole cavity is filled. These cells later undergo further divisions, but in all cases, apparently, nuclear divisions are accompanied by c'dl-formation. Not infrequently a group of cells, differing somewhat in appearance from the endosperm-cells, can be seen at the base of the embryo-sac (Figs. 27, 32). These may be possibly antipodal cells, but this point was not satisfactorily proven, and it is not impossible that in some cases, at least, they are merely somewhat modified endosperm cells. The embryo-sac shown in Fig. 23 was found in some of the Jamaican material referred to this species, but perhaps not correctly determined. In this case, as we have already stated, besides the egg-apparatus, there were but two nuclei, situated at the base of the embryo-sac, and evidently in the early prophases of division. A somewhat older embryo-sac (Fig. 24), evidently of the same type, was found, and from a comparison with these, it appears that the endosperm forma- tion results directly from the further division of the two basal nuclei found in the younger sac. This may be a further development of the type shown at Fig. 9, where the three apical nuclei were already arranged like an egg-apparatus, while but a single nucleus occupied the base of the sac. The complete absence of antipodal cells and polar nuclei in these instances, and the development of endosperm without the preliminary nuclear fusion, is certainly noteworthy. The embryo-sac in Aglaone 7 na becomes strongly bent as it grows. The peculiar mass of cells referred to, differing in appearance from the endosperm-cells (Figs. 27, 32), while in some cases to be interpreted as a mass of antipodal cells, may possibly be an embryo in some instances, as unmis- takable young embryos have been found at the chalazal end of the sac ; and in some of these embryo-sacs of large size, and already filled with endosperm, no trace of an embryo can be detected at the micropylar end. 676 Campbell.— Studies on the Araceae. The embryo-sac in the ripe seed occupies relatively a small part of its bulk. The large development of the integuments and chalazal part of the ovule suggests the perisperm forma- tion of the Piperaceae or Cannaceae. The Embryo. The embryo may occupy the usual position at the micro- pylar end of the sac, but more commonly it is at some distance from the apex of the sac, corresponding to the lateral or even basal position of the egg-cell. The first divisions (Fig. 24) are probably always transverse, but no well-defined suspensor is developed, this doubtless being associated with the early filling up of the sac with endo- sperm, which completely invests the young embryo. The cell next the wall of the embryo-sac may be regarded as a suspensor cell, but it does not become enlarged, nor give any other evidence of being functionally important. The subsequent divisions of the embryo do not show an absolute regularity. The strikingly pointed form of the young embryo shown in Fig. 26 recalls the embryos of some Grasses ; but this does not appear to be by any means always charac- teristic of the young embryo of Aglaonema. As the embryo grows it assumes an elongated form, but for a long time there is no differentiation of the external parts, nor are the tissues at all clearly defined. The enlarging embryo encroaches rapidly upon the endosperm, and fills almost completely the upper part of the embryo-sac. The greater part of the embryo is composed of the cotyledon, which becomes somewhat club-shaped and expanded at the end, which crowds into the enlarged chalazal part of the embryo-sac, destroying the endosperm as it grows, and leaving but a small part of it intact (Fig. 33). The tissues of the embryo are almost perfectly uniform, and the boundaries of the different organs very vaguely defined. The hypocotyl is very short, and although a median section of the root-end of the embryo (Fig. 31) shows some slight differentiation of the primary tissues, this is very imperfect. In the older embryo Campbell. — Studies on the Araceae. 677 (Fig. 34 a), a single layer of root-cap cells could be seen, but the tissues of the root-apex show very little evidence of a definite arrangement, and the same is true of the stem- apex (b), whose exact position it is impossible to determine. Aglaonema pictum. A brief examination was made of A. pictum , which closely resembles in general appearance A. commutatum , but which shows notable differences in the development of the ovule. The cells of the ovule are decidedly smaller, with correspond- ingly small nuclei, so that the two species are readily dis- tinguishable in this way. More important, however, is the marked difference in the development of the embryo-sac. So far as one can judge from an examination of a consider- able number of mature embryo-sacs of A. pictum, this species shows none of the variability so characteristic of A . com- mutatum. In all the specimens examined, the embryo-sac was not essentially different from other typical Angiosperms. The hemispherical egg-cell was accompanied by two large and conspicuous synergidae. Small but perfectly character- istic antipodal cells were at the base of the sac, and a single large endosperm-nucleus, evidently the product of the fusion of two polar nuclei, was conspicuous. Numerous starch granules were present in the sac, especially around the endosperm-nucleus — a not unusual feature of the embryo- sac in some other Araceae, e. g. Dieffenbachia. Except for the slightly lateral position of the egg-apparatus, A. pictum conforms entirely to the ordinary angiospermous type, and it is very remarkable that the apparently closely related A. commutatum should show such an extraordinary difference in the development of the embryo-sac. The ripe pollen-spores of A. pictum contain two generative nuclei, in which respect they differ from those of Dieffenbachia seguine , where there is but a single generative nucleus. Symplocarpus 1 also shows but a single generative nucleus in the ripe spore. 1 Duggar, Bot. Gazette, xxix, Feb. 1900. 678 Campbell. — Studies on the Araceae. Spathicarpa sagittaefolia. The genus Spathicarpa 1 includes four very characteristic South American Aroids. The flowers, which are of the simplest possible structure, are borne directly upon the upper surface of the green leaf-like spathe, no spadix being de- veloped. The flowers are arranged, in rows, staminate and pistillate flowers being intermingled. The staminate flower consists of a peltate synangium borne upon a stalk, and closely resembles the peltate sporophyll of Equisetum. The pistillate flower (Fig. 35) consists of a single peg-shaped carpel, terminating in a small stigma. No perianth is present, but between the flowers are numerous small nearly sessile staminodia. The great simplicity of the flowers suggested that the embryo-sac might possibly show correspondingly primitive characters, but this was not found to be the case, although there were some interesting peculiarities which will be con- sidered presently. The material used, like that of Aglaonema , was collected at Kew, and all belonged to one species, vS. sagittaefolia. A brief reference to the structure of the embryo-sac in this species has already been published 2 , but a mistake was made in the interpretation of certain structures, which has since been corrected. The peg-shaped carpel of the exceedingly simple flower is tipped by a small stigma composed of the usual papillate cells. The short style merges gradually into the ovary, which is completely filled by the single basal orthotropous ovule (Fig. 35). Both integuments are well developed, and, as in Aglaonema , the young embryo-sac soon destroys the lateral tissue of the nucellus, and thus comes into direct contact with the inner integument. The earliest stages of the embryo-sac were not seen, but from the youngest ones which could be found it is evident 1 Engler and Prantl, 1. c., p. 145. 2 Campbell, American Naturalist, Oct. 1902. Campbell, — Shi dies on the Araceae . 679 that there is no marked departure from the usual course of development. Whether the embryo-sac mother-cell arises at once from the primary archesporial cell, or is formed after division of the latter, could not be determined. The apical part of the nucellus persists as in Aglaonema y but is perhaps a little larger, relatively. In the youngest case met with (Fig. 36) the primary nucleus of the embryo-sac had already divided, and the daughter-nuclei, which were placed at opposite ends of the sac, were dividing, the division of the two taking place simultaneously, and the embryo-sac at this stage presented the usual appearance. No attempt was made to follow in detail the development of the sac up to the time of fertilization, as it was evident that it was in no way peculiar. The three cells of the egg- apparatus are nearly similar, and taper into the narrowed micropylar end of the sac. The polar nuclei are just above the three antipodal cells (Fig. 39), and their fusion into the endosperm nucleus is completed some time before fertilization takes place. In most cases observed, the fusion was com- plete. The antipodal cells are surrounded by distinct mem- branes, and while not noticeably conspicuous, are readily demonstrable. Owing to the small size of the nuclei the plant does not offer special facilities for studying the phenomena of fertiliza- tion, and no attempt was made to follow these in detail, although in several cases the sexual nuclei were observed in process of fusion. The process is evidently slow, and before it is complete the egg has increased perceptibly in size, and the pollen-nucleus, which is smaller than the egg-nucleus, becomes much flattened against the latter, with which it finally merges completely (Figs. 41, 44). The fusion-nucleus is not noticeably rich in chromatin, but has a conspicuous nucleolus. In the cytoplasm of the egg there are formed numerous small starch-grains which become larger before the first division occurs in the young embryo. These starch grains disappear during the early cell-divisions in the embryo, and are probably used in the formation of the cell-walls. 3 A 68o Campbell. — Studies on the Araceae. In the specimen figured in Fig. 37 one of the synergidae was conspicuous, while the second one was smaller, with a smaller nucleus ; whether this inequality is frequent in Spathicarpa was not determined. The Endosperm. The endosperm-nucleus increases a good deal in size before its first division. It lies just above the antipodal cells, and is imbedded in a mass of granular cytoplasm, which exhibits a more or less reticulate appearance in sections, probably indicating a vacuolate structure in the living state. The endosperm-nucleus has a conspicuous nucleolus, and is much richer in chromatin than the egg-nucleus. The first division of the nucleus was not seen, but from the appearance of the very young endosperm there is little question that the first division results in the cutting off of a basal endosperm-cell from the embryo-sac. The youngest stage observed (Fig. 40) consisted of three basal endosperm-cells, with exceedingly delicate membranes, and a fourth nucleus lying free in the base of the undivided portion of the embryo-sac. From a study of older stages, it is clear that the development of the endosperm proceeds from the base toward the apex of the sac, which soon becomes entirely filled with the cellular endosperm. The large, thin-walled primary endosperm-cells divide further, so that the cells of the endosperm become smaller and their membranes thicker. The Antipodal Cells. The three small antipodal cells present at the time of fertilization are stimulated into active growth and show an extraordinary development. Not infrequently, in somewhat later stages, four or occasionally more antipodal cells are present, but it is probable that the increased number is due to a division of one or more of the original antipodal cells, subsequent to fertilization. The small compressed antipodal cells of the embryo-sac at the time of fertilization elongate Campbell. — Studies on the Araceae. 68 1 rapidly to many times their original dimensions, and show every indication of extremely active growth. The cytoplasm is abundant, and the small nuclei enlarge rapidly, becoming extremely conspicuous. At this period (Fig. 42) the enlarged antipodal cells so closely resemble the young endosperm that they were at first mistaken for them, and this led to the erroneous statement made in a former article. The walls of the antipodals become thicker, and they ultimately reach gigantic dimensions, being easily seen in sections by the naked eye (Fig. 56). This enlargement is accompanied by a corresponding growth of their nuclei, which become many times larger than those of the endosperm-cells. At first they show a perfectly normal structure, but later there are evidences of disintegration. The nucleoli become immensely enlarged (Fig. 59), and finally very irregular in form, and the reticulate structure of the active nucleus becomes more or less completely broken down, and shows many evidences of disintegration. From their close resemblance to the active young endosperm- cells, there can be no doubt that the antipodals function as endosperm during the early development of the fertilized embryo-sac. The great enlargement of the antipodal cells is not peculiar to Spathicarpa among the Aroids. Hofmeister 1 figures enlarged antipodal cells in Arum orientate , and the writer has noted the same phenomenon, accompanied by increase in their number, in Lysichiton. In the latter there is also the great enlargement and subsequent degeneration of the nuclei of the antipodal cells. It is highly probable that a similar condition will be found in other genera. The Embryo. The fertilized egg increases slowly in size, but there is no division of the embryo until the embryo-sac is nearly or quite filled with endosperm, so that almost from the first the embryo is completely surrounded by the endosperm-tissue, 1 1. c., PI. VII, fig. 4 . 3 A 2 682 Campbell. — Studies on the Araceae. and, as might be anticipated, the suspensor is very rudi- mentary. The first division is transverse and cuts off a small pointed basal suspensor-cell, which, however, undergoes very little further growth. The next divisions are probably not always exactly the same. Usually the second wall is vertical (Fig. 45) and divides the embryonal cell into two nearly equal parts. Sometimes before this vertical wall is formed an oblique wall may cut off a small cell (Fig. 46) in contact with the suspensor-cell. The latter does not always show the pointed form which usually distinguishes it. Following the first vertical wall in the embryonal cell, there are usually two transverse walls, intersecting it and dividing the embryo into nearly equal quadrants, and these maybe divided into octants, although it is not probable that this is always the case. Figs. 49-52 represent nearly median sections of embryos of about the same age, showing the variation in form as well as in the cell-arrangement and the character of the rudimentary suspensor. For a long time there is no evidence of the development of the external organs, nor is it possible to trace any definite relation between these and the earlier divisions of the embryo. The stem-apex arises in a lateral depression at a point a little below the middle of the embryo, the region below developing the hypocotyl and root, the part above, the cotyledon (Fig. 53). In the origin of the organs of the embryo, Spathicarpa does not differ essentially from the commonest type of the Mono- cotyledons. The tissues of the embryo remain almost per- fectly homogeneous, and even in the root, where the arrange- ment of the tissues is most regular, the limits of the different tissue systems are very imperfectly defined. At the root end, in the most advanced embryo, there may be seen the rudi- mentary suspensor, and although the tissues are somewhat better defined than in the embryo of Aglaonema , still they are rather vague. The root-cap is not clearly delimited, nor are the meristems below it at all clearly defined. Some evidences of a central strand can be made out, above which Campbell . — Studies on the Araceae. 683 is a layer of meristem, which probably serves as the initial for all the outer tissues. The epidermal cells of the stem-apex are narrower than the ordinary epidermal cells (Fig. 55), but otherwise the stem- apex is indistinguishable, except from its position. The cotyledon constitutes the greater part of the embryo, and its base partially encloses the inconspicuous stem-apex, as is so often the case among Monocotyledons. None of the permanent tissue elements were recognizable in the oldest embryos which were available, and only the slightest traces of the young vascular bundles could be de- tected. The embryo in the ripe seed occupies only a small portion of the large embryo-sac, which is filled with the endosperm-tissue (Fig. 56). As the seed approaches maturity the endosperm-cells de- velop numerous small starch-granules. The growing embryo uses some of this, so that the cells immediately surrounding the embryo contain but little starch, while those in the central part of the sac (Fig. 58) contain a great deal. The basal cells of the endosperm become much larger than the upper ones, and their walls are much thickened, so that they show a certain likeness to the enlarged antipodal cells. Like the latter, their nuclei are also enlarged, although not nearly to the same degree, and show some evidences of disintegration. Summary. 1. In both Aglaonema and Spathicarpa the pistillate flower consists of a solitary carpel containing a single basal ovule, probably of axial origin. 2 . The embryo-sac of Aglaonema commutatum shows many deviations from the usual type. These consist first in a varying number of embryo-sacs, ranging from 1 to 3. Where two or three are formed, this may be from a division of a common archesporial cell, but in some cases it looks as if these originated independently from hypodermal cells. All of these embyro-sacs usually undergo the first nuclear divisions, but probably only one ever becomes fully developed. The 684 Campbell. — Sludies on the Araceae. second peculiarity is the extraordinary variation in the number of nuclei in the embryo-sac, and in the character of the struc- tures developed in it. The number of nuclei ranges from 4 to 12, and the polarity is usually but slightly indicated. Multiple nuclear-fusions are of common occurrence, and it is often impossible to be certain which of the structures represent the egg- apparatus, and which the antipodal cells. 3. In specimens of an undetermined species (Dieffenbachia Aglaonema Hort.), perhaps identical with A. commutation , the endosperm may arise from the direct division of two nuclei (or possibly a single one) at the base of the sac, without any formation of polar nuclei. 4. A. pictum does not depart to any marked extent from the usual angiospermous type. The pollen-spore of this species has two generative nuclei. 5. The embryo of Aglaonema , although reaching a large size, shows little differentiation of its external parts, and its tissues are almost perfectly homogeneous. In the ripe seed it almost completely fills the embryo-sac. The nucellus is relatively small, but the integuments and base of the ovule are very massive, and comprise the greater part of the seed. 6. In Spathicarpa the development of the ovule and embryo- sac are of the usual type. After fertilization the antipodals become very greatly enlarged, and one of them may divide, so that there are often four antipodals present. The nuclei of the antipodal cells become enormously enlarged. 7. The embryo of Spathicarpa remains small in the ripe seed. The external organs are indicated, but the tissues remain but slightly developed. 8. The development of the endosperm in both Aglaonema and Spathicarpa proceeds gradually from the base of the sac until it is completely filled. It is probable that this is the ordinary method of endosperm-formation in the Araceae. Campbell. — Studies on the Araceae. 685 EXPLANATION OF FIGURES IN PLATES XXX, XJCXI, AND XXXII. Illustrating Professor Campbell’s Studies on the Araceae. PLATE XXX. All figures refer to Aglaonema commutatum. Figs. 1, 7, 15, Leitz, oc. 3, obj. 3. Figs. 12, 13, 14, 16, 17, Leitz, oc. 1, oil imm. 1/1 6 ; the other figures, Leitz, oc. 1, obj. 7. Fig. 1. Median longitudinal section of young ovule, showing the young embryo- sac, m } and the two integuments in lf in 2 . Fig. 2. The nucellus and embryo-sac, more highly magnified. Fig. 3. Oblique section of the nucellus, showing two young embryo-sacs, apparently derived from the division of a common mother-cell. Fig. 4 a, b. Two sections of young embryo-sac with two nuclei, c, Nuclei from the lateral cells of the nucellus, more enlarged, showing the very much compressed form. Fig. 5. Section of a nucellus with two young embryo-sacs; each contains four nuclei. Fig. 6. Embryo-sac containing four nuclei, all at the micropylar end. (Three only shown in the section.) Fig. 7. Nearly median section of an ovule with three embryo-sacs. Fig. 8. The details of the sacs shown in Fig. 7, more highly magnified, a f contains a single nucleus ; b, eight nuclei in two groups, partially fustd ; c d , and e, the details of sac c : d, antipodals (?), 0, egg (?), c , fusing endosperm nuclei. Fig. 9. Sections of embryo-sac with four nuclei, three at the micropylar end, a single one, b, at the chalazal end. Fig. 10. Sections of a sac with eight nuclei, in two groups of four ; no definite polar nuclei recognizable. Fig. 11. Two sections of an ovule with three large cells (embryo-sacs?), but probably abnormal. The largest of the three cells contained but two nuclei (r). What looked like a pollen-tube,/, t ., occupied the micropyle, above the apex of the nucellus. Fig. 12 a. Upper part of nucellus, showing the pollen-tube, p. t. The cell with the two nuclei probably represents a second, imperfect embryo-sac. The lower embryo-sac contained twelve nuclei, in three groups, b, the four antipodal nuclei, c, four nuclei fusing, presumably to form the endosperm-nucleus. Fig. 13. Two sections of the apex of a sac, with what seemed to be a very broad pollen -tube, p. containing a generative nucleus, g. There were four cells at the apex, of which two hemispherical ones, 0, o ' , were much alike. One of these is probably the egg-cell. Fig. 14. Nuclei from the cavity of the embryo-sac shown in Fig. 13. There were four nuclei, two in process of fusion, and two (only one shown in the section) which were apparently disintegrating. No antipodal cells were present. Fig. 15. Section of a group of three embryo-sacs ; the two upper ones degeneia- 686 Campbell. — Studies on the Araceae. ting. At the base of the lower one were two very large nuclei, and there were two free nuclei in the cavity of the sac. Figs. 1 6, 17. Nuclei from the lower sac shown in Fig. 15 more highly mag- nified. PLATE XXXI. Figs. 18, 22, 28 and 31 refer to Aglaonema commutatum , the others to a very similar, but possibly different, species grown at the Hope Gardens, Kingston, Jamaica, under the name Diejfenbachia Aglaonema. Figs. 19, 25, 28, 32, Leitz, oc. 3, obj. 3 ; 33, about 20 diameters ; the others Leitz, oc. 1, obj. 7. Fig. 18. Embryo-sac with ten nuclei, four at the chalazal end ( a ), the other six in a group at one side of the sac (two only shown in the section b). Fig. 1 9. Section of a fertilized sac, showing the forming endosperm at the base. Fig. 20. Young embryo, from near the chalazal end of the same embryo-sac. Fig. 21. Young endosperm of the same sac. Fig. 22. Group of four [antipodal (?)] cells from the same sac. Fig. 23. Embryo-sac with egg ( 0 ) and two synergidae ( c ), at the apex, and two nuclei, preparing to divide, at the antipodal end. Fig. 24. A similar embryo-sac, after fertilization. At the apex a young embryo, surrounded by large celled endosperm, apparently derived from the division of the basal nuclei shown in Fig. 23. Fig. 25. An older embryo-sac, with young embryo, em. Fig. 26. Two sections of an older embryo, sus , suspensor-cell. Fig. 27. Base of an older embryo-sac, with mass of tissue different from the endosperm, and possibly representing the embryo, as no other evidence of an embryo can be found. Above this mass was an elongated body ( p . t. ?), which may possibly have been the pollen-tube. Fig. 28. Section of embryo-sac, with older embryo, em. Fig. 29. Micropylar (root-)end of an older embryo. Fig. 30. Apex of the cotyledon of the same embryo. Fig. 31. Root- end of an embryo, showing slight differentiation of the tissues. Fig. 32. Embryo-sac, with mass of cells, perhaps an embryo, at the chalazal end. No embryo was present at the apex of the sac. Fig. 33. Section of older ovule, the embryo filling most of the embryo-sac end, the basal endosperm. Fig. 34. a, root-end ; b , central portion of the embryo shown in Fig. 33, st, the future stem-apex. PLATE XXXII. All figures refer to Spathicarpa sagittaefolia. Figs. 35, 53, Leitz, obj. 3, oc. 3 ; Fig. 56, about 8, Fig. 57 about 45 diameters ; Figs. 36, 37, 41-44, Leitz, oil imm. 1/16, oc. 1 ; the others, Leitz, obj. 7, oc. 1. Fig. 35. Longitudinal section of mature pistillate flower of Spathicarpa sagittae- folia ; m, embryo-sac. Fig. 36. Young embryo-sac ; the second nuclear division is taking place ; the chalazal nucleus was also dividing. Fig. 37. a , egg-apparatus ; b , endosperm-nucleus from a mature embryo-sac. Fig. 38. Antipodal cells and endosperm-nucleus, from an embryo-sac of about the same age as Fig. 37. Campbell. — Studies on the Araceae. 687 Fig. 39. Antipodal cells and polar nuclei from a younger sac. Fig. 40. Embryo-sac after fertilization. The sexual nuclei are fusing in the egg- cell, and the endosperm formation has begun. Fig. 41. Fertilized egg of Fig. 40, more enlarged, showing conjugation of the sexual nuclei. Fig. 42. Chalazal end of the same sac, more highly magnified, showing the enlarged antipodal cells and young endosperm. Fig. 43. Chalazal end of an older embryo-sac. Fig. 44. Egg-cell, with fusion of the sexual nuclei almost completed. One of the synergidae is clearly evident. Figs. 45-47. Young embryos, sus , suspensor. Fig. 48. Young embryo surrounded by endosperm. Figs. 49-52. Median longitudinal sections of older embryos, showing the variation in form, and in the development of the suspensor. Fig- 53* Three longitudinal sections of an older embryo ; a , a nearly median section ; st , stem-apex ; r , root ; cot , cotyledon. Fig. 54. Nearly median section of the root portion of the same embryo as Fig. 53, more highly magnified. Fig. 55. Central region of the same embryo showing the stem-apex, st. Fig. 56. Longitudinal section of a nearly full-grown seed, showing the small embryo, eni , and the large antipodals, ant ; enlarged about eight times. Fig. 57. The lower part of Fig. 56, more enlarged. Fig. 58. Endosperm cells from a nearly ripe seed. Fig. 59. Nucleus from one of the antipodal cells. 1 Annals of Botany: D.H.Cautnp'bell lei. C AM PBE LL.- ARACEAE Vol.XVI[,Pl.XXX. University Press, Oxford. ftnnals of Botany: Vol.XVH,PUXX. D.H.Ca,nip\>ell del. CAMPBELL - ARACEAE. IE. 16 . University Press, Oxford. / \ * ft 7 b. Mmols' of Botany-. D-H. Campt ell del. CAMPBELL. - ARACEAE. } voi.miPi.mi. Jtxmxils of Botany. vouvqpi.xxxi D.H. Campbell del. CAMPBELL - ARACEAE. Jbnuals of Botany. D.H. Ca,mp"bell del. CAMPBELL - ARACEAE. Voi.xvii 7 Pixm. University Press, Oxford. ftrvncds of Botany: CAMPBELL - ARACEAE. Vol.XVII,Pl.XXXII. 5 4 . 55 . University Press, Oxford . 59 . arvbr Observations on the Anatomy of Solenostelic Ferns. Part II. BY D. T. GWYNNE- VAUGHAN, M.A., Demonstrator in Botany at the University of Glasgow. With Plates XXXIII, XXXIV, and XXXV. HE terms used to indicate the different types of vascular JL arrangement in plants have recently become so numerous and varied that before going on to the descriptive part of this paper it is necessary to explain why some of those employed in it were chosen. So far as the Cyatheaceae and Poly- podiaceae are concerned it is no longer advisable to make use of Van Tieghem’s term ‘polystely’ for those cases in which the single central cylinder of the young plant becomes divided up into several separate portions, because it is now quite clear that none of the so-called * steles ’ that result can properly be regarded as equivalent to the original central stele. It has therefore been decided to adopt the term ‘ dictyostele/ recently proposed by Brebner 1 , for the tubular network of vascular tissue that arises by the occurrence and overlapping of gaps in a solenostele. The separate portions into which 1 Brebner, On the anatomy of Danaea and other Marattiaceae, Annals of Botany, vol. xvi, no. lxiii, p. 523, 1902. [Annals of Botany, Vol. XVII. No. LXVIII. September, 1903.] 690 G wynne- Vaughan . — Observations on the the original central stele has in this manner become broken up will be called ‘ meristeles.’ The most primitive type of vascular system that occurs in the Filicineae is probably the single protostelic central cylinder of the mature stem of Lygodium , the most important char- acteristic of which is that the continuity of the central xylem mass is not interrupted by the subsidence of the external tissues, cortical or vascular, at the departure of the leaf-traces. Such a structure has not yet been found in the mature stem of any of the Cyatheaceae or Polypodiaceae, although it is sometimes to be met with at the very base of the young plant. The solenostele holds an intermediate position between this simple protostelic type and the more complicated dictyostelic arrangements most frequently ex- hibited by these two orders, and it is chiefly due to this fact that the solenostele becomes a structure of particular interest. The earliest reference to the solenostelic type of structure was made in 1838 by Robert Brown 1 , who noted the presence of a complete ring of vasa scalariformia in Polypodium Hors- jieldii , R. Br. ( Dipteris conjugata , Reinw.). A similar structure has since been recorded by various botanists in a large number of different Ferns, although many of their so-called ‘pith- containing wood-cylinders ’ have proved upon investigation to be really dictyosteles and not solenosteles. Most of the examples included in this paper have already been mentioned at one time or another, and although most of the previous descriptions have been more or less inadequate or incorrect, those given by Karsten 2 and Mettenius 3 can hardly be improved upon. The true solenostele is not of very general occurrence, although it is to be met with in several different genera, e. g. Dicksonia , Davallia , Lindsay a, Hypolepis , P ter is, 1 Horsfield, Plantae Javanicae, p. 2. 2 Die Vegetationsorgane der Palmen. Abhandl. d. K. Acad. d. Wissensch. z. Berlin, p. 186, 1847. 3 tjber den Bau von Angiopteris. Abhandl. d. K. Sachs. Gesellsch. d. Wissen- sch., Bd. vi, p. 531, 1864. 691 Anatomy of Solenostelic Ferns. Pellaea , Poly podium, and Jamesonia. However, in these and other genera ( Cheilanthes , N othochlaena, Adiantum , Gymno- gratnme , Antrophyum , and Vittaria) a number of transitional types related to the solenostele are to be found, which will also have to be taken into consideration. So many different species taken from several different genera have been ex- amined that it is impossible to deal with them individually. It would also be very inconvenient to treat each genus separately, because their anatomical characteristics do not, for the most part, run parallel with their systematic position. Therefore, in the first part of this paper, where the general vascular arrangement in the stem is described, the plants will be dealt with in groups which will, as far as possible, lead up to the more interesting results that have come to light during the investigation. A few points of interest relating to the structure of the vascular bundles of the petiole, the lateral shoots, and the roots will be mentioned, and the histology of the vascular system will also be considered, but only in a very general manner. Typical Solenosteles. A perfectly solenostelic vascular system was found in the stems of all the species included in the following list 1 : Davallia hirsuta , marginalis , strigosa , platyphylla , hirta, Spelnncae , Novae-Zelandiae , Linds ay a retusa , Dicksonia apii - folia , cicutaria , scabra , punctiloba , davallioides , P ter is scabe - rula, incisa , ludens , Pellaea atropurpurea , falcata , and Jame- sonia imbricata. All these Ferns have a creeping, more or less dorsiventral rhizome with the leaves arranged in two rows on the upper surface, and their solenosteles differ from each other and from that of Loxsoma , as described in Part I of this paper 2 , in so slight a degree that the same description 1 For the sake of uniformity the nomenclature of Hooker’s ‘ Synopsis Filicum ’ will be adopted as far as possible throughout. It will therefore be unnecessary to give the authorities for the names, unless they are not recognized as such in the 1 Synopsis Filicum.’ 2 Annals of Botany, vol. xv, no. lvii, 1901. 692 Gwynne- Vaughan. — Observations on the will serve for them all. The gaps formed in the solenostele by the departure of the leaf-traces never overlap. The xylem- ring is surrounded, both externally and internally, by a complete ring of phloem and pericycle, and the whole is delimited from the ground-tissue on both sides by a well- marked endodermis. The leaf-trace departs from the soleno- stele of the stem as a single continuous vascular strand, usually curved so that it has a section similar in form to a horse-shoe or an arch. This curved strand is so attached to the solenostele that its concavity faces the median dorsi- ventral plane of the rhizome, either directly, as in Dicksonia punctiloba (PL XXXIII, Fig. 1), Pteris incisa, &c., or else more or less obliquely, as in Dicksonia apiifolia (Fig. 2), Davdllia Spelnncae (Fig. 3), &c. In Pteris ludens and Jamesonia imbricata the leaf-trace faces directly towards the apex ; a position it also occupies in L ox soma (Part 1 1 , Fig. 4) ; in this Fern, however, the leaves are inserted along the upper surface in a single median row. For some time before it actually departs, that portion of the solenostele destined to form the leaf-trace is usually well defined as a protrusion which is some- what thinner than the rest of the vascular ring (Figs. 2 and 3). The leaf-gap generally closes up at the same time as the acroscopic flange of the leaf-trace departs, or immediately after- wards. It may, however, remain open for a short distance above the leaf, as in Davallia Spelnncae (Fig. 3), Pteris ludens, Jamesonia imbricata, and others. The free margin of the leaf-gap is usually of the same thickness as the rest of the solenostele, but in some cases it becomes more or less en- larged : Dicksonia apiifolia, cicutaria, Davallia hirta. The enlargement is entirely due to the increased thickness of the xylem-ring in this region ; in the two Dicksonias it is often twice as thick as elsewhere in the stele, so that the free margin of the leaf-gap projects markedly towards within. This marginal thickening is a feature of considerable interest, and those Ferns in which it reaches a more conspicuous development will be trea'ted separately later on. When 1 Ann. of Bot. vol. xv. PI. III. Anatomy of Solenostelic Ferns . 693 lateral shoots are borne by any of the above Ferns they are always inserted upon the base of the petiole, and their vascular systems are joined on to one or the other margin of vascular strand of the petiole (cf. Figs. 4, 5, and 6). A perfect solenostele is also present in the stem of Hypolepis tenuifolia, millefolium , distans, and repens , but certain additional peculiarities occur in relation to the insertion of the leaf- trace which will require especial description. The stem is a dorsiventral rhizome, as in the Ferns mentioned above, with the leaves arranged in two rows upon the upper surface. The leaf-trace becomes definitely marked off from the rest of the solenostele some distance before it actually departs as such, and the gap formed by its departure runs forward a considerable distance before it is closed up again. The leaf- trace consists of a single curved strand in all cases except in H. tenuifolia , where it departs as two separate pieces, and later on in the petiole breaks up into several. One or more lateral shoots are given off from the base of each leaf in all four species. If only one is present it always arises from the basiscopic margin of the leaf-trace, if there are two or more, then the lowest on the basiscopic side is always stronger and further developed than the others (Fig. 6). In order to form the vascular system of a lateral shoot the margin of the leaf-trace curls inwards on to itself, and the curved portion eventually separates off as a gutter-shaped stele which rapidly closes up into a complete cylinder. Reference to Figs. 4, 5, and 6 will show how this takes place, and also how the presence of the lateral shoots affects the form of the leaf-trace and the manner of its departure: At the very base the leaf-trace is very irregular in form, and its concavity is directed towards the apex of the stem, but once it has become free from the steles of the lateral shoots it exhibits the customary form of an arch, the concavity of which faces the median dorsiventral plane of the rhizome. The structure of the node in these Ferns is still further complicated by the appearance of certain small vascular strands which connect up the free margins of the leaf-trace, 694 G wynne- Vaughan. — Observations on the shoot-stele, and stem-stele with each other. In my specimens two such strands were usually present. The most constant of these was one running from the free margin of the gutter- shaped stele of a lateral shoot to that margin of the leaf-trace from which the shoot in question arose (a in Figs. 4, 5, and 6). The other strand, which was sometimes wanting, ran either from the free margin of the gutter of the basiscopic shoot to the opposite (acroscopic) margin of the leaf-trace (b in Figs. 4 and 6), or it started from the free margin of the leaf-gap itself and ran to the acroscopic margin of the leaf-trace (c in Fig- 5 )- A perfect solenostele of almost exactly the same nature as that described in the above species of Hypolepis was also found in Polypodiu 7 n punctatum . The lateral shoots arose in the same way, and, what is even more interesting, the small addi- tional strands in the neighbourhood of the leaf-gaps were also present. In my specimen they had the same position and course as those marked a and c in the diagrams of Hypolepis. Several other cases of solenostely were met with in different plants, which possess special features of such importance that it will be more convenient to deal with them separately later on. Transitional Types. Vascular systems were found in a large number of Ferns belonging to several different genera which seem to represent a series of stages transitional, or intermediate, between sole- nostely and dictyostely. The examination of these forms makes it quite clear that the dictyostely of the Cyatheaceae and Polypodiaceae is primarily due simply and solely to the overlapping of the leaf-gaps in a solenostele ; although it is not to be denied that gaps may sometimes occur in the vascular cylinder which are not in any way related to the insertion of the leaves. It appears also that two different factors may be concerned in bringing about this overlapping of the leaf-gaps. In the first place, it is evident that if the Anatomy of Solenostelic Ferns . 695 leaf-gaps remain open long enough after the departure of the leaf-trace they will eventually overlap ; again, the same result will also be obtained if the leaves be crowded sufficiently close together, although the leaf-gaps may close up comparatively rapidly. In some of the intermediate forms the leaf- gaps only over- lap now and then, so that the stem, to a certain extent, still remains in a solenostelic condition. In others again the over- lapping is more general, and a complete stelar cylinder is only to be found at rare intervals. It will therefore be under- stood that cases sometimes arise where it is impossible to say definitely of the vascular system of the plant as a whole that it is either solenostelic or dictyostelic. The investigation of these forms shows that the distinction drawn by De Bary 1 between the dorsiventral and the radial type of vascular arrangement in dictyostelic Ferns is one of considerable value, because it will be seen that the structural features of the two types depend upon the different methods by which they are derived from the solenostele. The transition from solenostely to dictyostely in a dorsi- ventral rhizome with two rows of leaves, one on either side of the upper surface, will be first considered. A reference to the diagrams (Figs. 7 and 8) will show the effect of closely crowded leaves, or of long persisting leaf-gaps upon the solenostele. It is seen that the dorsal internodal portion of the solenostele has become so reduced that it is now no more than a mere strand running across between each leaf-insertion from one margin of the large ventral portion of the solenostele to the other. A structure such as this may be found in the rhizomes of Nothochlaena Marantae (Fig. 7), trichomanoides , ferruginea, Pellaea rotundifolia (Fig. 8), andromedae folia, A dian- turn trapeziforme, Kaulfussii, and Gymnogramme vestita. A similar type appears also to be present in A n trophy urn reticu- latum , but it is a little exceptional and will be referred to again later on. Transverse sections of the stems of these Ferns will in most cases exhibit a single large gutter-shaped 1 Comparative Anatomy, pp. 284 and 287 (Engl. ed.). 3 B 696 Gwynne- Vaughan. — Observations 071 the meristele, but in some a small additional dorsal one will also be present. Bearing in mind the structure just described one is now in a position to understand the somewhat aberrant form of solenostely found in the dorsiventral Ferns Cheilanthes lendi- gera and microphylla. So far as the endodermis and pericycle are concerned each leaf-gap in the stele is closed up before the next above is formed, but the leaf-gap in the xylem-ring remains open until it overlaps the gap formed in the xylem by the departure of the leaf-trace next above. In this manner a small separate xylem-strand is produced within the stele which crosses over between each leaf-insertion from one side of the open xylem-ring to the other ; having precisely the same course and origin as the free dorsal meristele in the forms described above. In the more perfectly dictyostelic Ferns the dorsiventral type of vascular arrangement becomes much more com- plicated, but, in most cases, the manner of its origin from the solenostele is essentially similar to that already described, although it may differ considerably in detail. For instance, in Asplenium scandens the internodes are long, and the course of the dorsal meristele as it runs across from one side of the ventral portion of the solenostele to the other is a very oblique one ; moreover, since the two rows of leaves are on exactly opposite sides of the stem, the dorsal meri- stele is almost as large as the ventral. In a dissection of the stem, therefore, two fairly large meristeles are to be found, very similar to each other in form and size, and between each two leaf-insertions the dorsal meristele is seen to cross slowly over from one side of the ventral meristele to the other. If the dorsal meristele were to pursue a straight course, and instead of coming into bodily contact itself with the ventral meristele, as in Asplenium scandens and the cases mentioned above (Figs. 7 and 8), it were to keep up its connexion with it at the same points as before by means of short transverse strands or sutures, a structure would then result essentially Anatomy of Solenostelic Ferns. 697 similar to that described and figured by Mettenius 1 and De Bary (loc. cit.) in several different dorsiventral Ferns. All the Davallias of the section Humata that were examined belong to this type, and also most of those belonging to the sections Eudavallia and Leucostegia. In some of these Ferns, however, the actual state of affairs is a little obscured by the fact that several separate leaf-traces are given off to each leaf, which run forward for some distance in the ground-tissue of the stem before they turn out into the petiole, also the two meristeles of the stem are often so similar to these in form and size that they are scarcely to be distinguished from them. Attention should also be drawn at this point to the vascu- lar arrangement described by Mettenius (loc. cit., p. 552 ) in a number of dorsiventral Ferns, of which Platycerium alcicorne may be quoted as an example. In these the dorsal meristele seems to be present as usual, but the ventral one appears to be broken up into an irregular meshwork of strands, the gaps in which bear no relation whatever to the leaf-insertion. In Ferns which have their leaves arranged radially in several rows all round a prostrate or an erect stem three or more leaf-gaps usually overlap at the same level, and the solenostele is broken up into just as many more or less equivalent meristeles arranged in a ring around the axis. If the structure is still but little removed from solenostely it may happen that two leaf-gaps only overlap at any one level, and then the vascular arrangement, when seen in trans- verse section, generally consists of a large gutter-shaped meristele with another small one lying across its opening (Figs. 9 and 10). Although this structure is very similar in appearance to that presented by the simpler forms of the dorsiventral type, it is really to be regarded as quite distinct, because the relative positions of the two steles change in accordance with the radial arrangement of the leaves. The following Ferns were found to be radially dictyostelic, but still remain very close to solenostely: Dicksonia Barometz (Fig. 17), P ter is tremula , ere tic a, flabellata , heterophylla 1 1. c., Taf. vii, viii. 3 B 2 6g8> Gwynne- Vaughan.— Observations on the pellucida , Taenitis blechnoides , Gy 7 nnogramme calomelanos (Fig. 9), Hemionitis palmata, Adiantum lunulatum , Lomaria semicordata (Plagiogyria bis errata, Met.) (Fig. 10). No particular form of leaf-trace is especially related to the simpler intermediate forms of dictyostely, either dorsiventral or radial. However, it generally consists of a single strand, as in Nothochlaena Marantae (Fig. 7) and Pteris tremula , or else it is divided into two separate portions, as in Adiantum trapeziforme and Gymnogramme calomelanos (Fig. 9). Whenever more than two rows of leaves are found upon the stem of a Fern they are nearly always arranged radially all round the axis, even though it may be a creeping or pros- trate rhizome. There are, however, a few in which they are inserted in several rows all upon the upper surface, and in these the rhizome is dorsiventral in structure, e. g. Pellaea cordata. It seems probable that they originally belonged to the radial type, and have become dorsiventral in a secondary manner in consequence of the prostration of the stem. It is also possible that they have been derived from a dorsiventral type with two rows of leaves by the intercalation of additional leaves between those already present. However, their anatomy has not yet been thoroughly investigated, and the question must be left open. SOLENOSTELES WITH INTERNAL ACCESSORY VASCULAR Strands. Attention has already been drawn to the fact that the free margin of the leaf-gap in Dickso 7 iia apiifolia and other solenostelic Ferns is considerably thicker than the rest of the solenostele, owing to an increase in the amount of xylem present at that point. In Dicksonia adiantoides this feature becomes so conspicuous and important that it requires especial description ; particularly so because it appears to give an explanation of certain complex modifications of the vascular system that occur in a number of other Ferns. Dickso 7 iia adiantoides has a dorsiventral rhizome with leaves in two rows on the upper surface, and a perfectly solenostelic vas- Anatomy of Solenostelic Ferns . 699 cular system. The leaf-trace consists of a single curved strand inserted so that its concavity faces the median dorsiventral plane of the rhizome, and the leaf-gap closes up at the same time as the acroscopic flange of the leaf-trace departs. The enlargement of the leaf-gap margin is so pro- nounced that it projects markedly towards the interior, and, what is more important, this projection is not confined to the limits of the open leaf-gap, as in the previous examples, but is continued as a ridge upon the internal surface of the soleno- stele throughout the whole length of the internode, running from one leaf-gap margin to the other (Fig. 11). In the immediate neighbourhood of the leaf-gap the additional xylem-elements that cause the internal projection of the margin are in more or less complete continuity with the rest of the xylem-ring, just as in Dicksonia apiifolia , &c., but in the internodes they become separated off as a distinct strand (Fig. 12), which may even be surrounded by a phloem- ring of its own distinct from that of the solenostele. This separate strand of xylem generally attains its greatest inde- pendence in the upper part of the internode, and is most closely fused with the xylem-ring of the solenostele towards the top of the leaf-gap. In my specimens the separate strand of xylem never became free from the endodermis and peri- cycle of the solenostele, but in a stout example it seems probable that along part of its course it may become com- pletely isolated in the central parenchyma. The protoxylem- elements of the solenostele are located in definite endarch or mesarch strands ; a similar protoxylem-group is sometimes to be found in the internal xylem-strand (Fig. 12). The insertion of the leaf-trace in this Fern is further com- plicated by the presence of lateral shoots and of one or two small vascular strands which run across the leaf-gap very much in the same way as those already described in Hypolepis. In this case they start from the internal surface, or from the basiscopic margin of the leaf-trace (Fig. 11), and run forwards to the free margin of the leaf-gap. The marginal thickening and the transverse strands were found at nearly all the leaf- 700 G wynne- Vaughan. — Observations on the gaps, but occasionally, both in the main axis and in the lateral shoots, one or the other, or even both of these features may be wanting. Seward and Dale 1 have described a thickening of the margins of the leaf-gaps in Dipteris conjugata (Reinw.) which should probably be regarded as of the same nature as that in Dicksonia adiantoides , only a step more advanced. For in this case it appears that the free xylem-strand has almost separated off from the solenostele altogether, being connected with it only at two points, between which a tongue of ground- tissue has inserted itself. From the description given by Boodle 2 3 it appears that a structure very similar to this is also to be found at the margin of the leaf-gaps of Gleichenia pectinata , and it is suggested that here again we have to deal with the same phenomenon as in Dipteris conjugata and Dicksonia adian- toides . One point of difference, however, is to be noted in the two last cases, which is that both flanks of horse-shoe- shaped leaf-trace depart at the same time, and both sides of the leaf-gap are similarly thickened. Before going on to describe the internal vascular strands that occur in the stem of Dicksonia rubiginosa it is necessary to point out certain very exceptional features that are also presented by the ordinary vascular cylinder of this plant. The habit of the rhizome and the insertion of the leaf-traces are essentially the same as in Dicksonia adiantoides. The leaf-gaps close up directly after the leaf-trace departs (Fig. 13), but nevertheless the vascular system cannot be regarded as a solenostele, because in addition to the leaf-gaps other lacunae occur in the stelar cylinder which have no relation to the leaf- insertion whatever. These lacunae occur somewhat irregularly, but chiefly along two lines on opposite sides of the creeping rhizome. They are sometimes comparatively short, but more 1 Structure and Affinities of Dipteris, &c., Phil. Trans., Series B, vol. cxciv, p. 499, and Fig. 4, 1901. 3 On the Anatomy of the Gleicheniaceae, Annals of Botany, vol. xv, no. lx, p. 730, 1901. Anatomy of Solenostelic Ferns . 701 often they form long splits interrupted by small meristeles passing across the lacuna from one side to the other. Although a completely closed vascular ring is sometimes to be met with in transverse sections of the internode, the most frequent appearance is that of two large curved meri- steles, one dorsal and one ventral, with or without one or two smaller ones lying between their margins. In this plant, therefore, an entirely exceptional kind of dictyostely has been attained without relation to the overlapping of the leaf-gaps ; indeed so far as that is concerned the vascular structure may still be regarded as solenostelic. So far as I am aware, in this respect Dicksonia rubiginosa stands unique among the Ferns. The accessory vascular strands found within the ordinary stelar cylinder vary in number from point to point. There were never more than three present in my specimen, and sometimes they all fused up to a single large curved strand. In their course through the internode they may branch and anastomose with each other, but they never come into contact with the internal surface of the ordinary stelar cylinder except in the neighbourhood of the nodes. At each node a single internal strand approaches the free margin of the leaf-gap, and gradually fuses with it until the two xylems are perfectly con- tinuous, presenting an appearance exactly as in Dicksonia adiantoides . As soon as the leaf-trace has departed it separ- ates off again and passes on as a free internal strand into the internode above. One internal strand at least was present in all parts of the specimen examined, even at the base of the narrow lateral shoots. Distinct mesarch protoxylem groups are to be found in them, which, however, do not appear to be in any way related to those of the leaf-trace. In this plant, again, the vascular systems of lateral shoots are usually to be found departing from the margins of the petiolar strand, and, as in Dicksonia adiantoides , small vascular strands are sometimes to be met with which run forward from the internal surface of the leaf-trace to the free margin of the leaf-gap. A still more conspicuous system of internal vascular strands 702 G wynne- Vaughan Observations on the is to be found in the stem of Pteris elata 1 which is an erect or oblique rhizome with the leaves arranged radially all round. The vascular system is perfectly solenostelic, and the leaf-gap closes up immediately after the departure of the leaf-trace. The curved leaf-traces are inserted with their concavities fac- ing directly towards the apex, which, moreover, appears to be always the case in all Ferns in which the stem grows erect. The appearance of the internal vascular system will vary according to the dimensions of the plant, and to the position of the section relative to the nodes (Fig. 14). In a rhizome of average thickness the internal system usually has the form of a large gutter-shaped strand or of a completely closed cylinder, the latter being generally present for some distance below each of the nodes. As the leaf-gap is approached from below a fairly large flat strand is seen to separate off from the internal vascular cylinder, which, travelling forwards and outwards, ends by fusing completely and finally with the anterior margin of the leaf-gap in the outer solenostele ; just as the latter becomes closed up again. The lacuna thus produced in the internal vascular cylinder converts it into a gutter which, however, gradually closes up in the internode above, so that a complete cylinder is again formed, usually for some distance before the next leaf-insertion is reached. Sometimes, on the other hand, two such gaps in the internal vascular system may overlap, so that two separate internal strands are occasionally to be met with. In large and especially well-grown rhizomes a second internal vascular system is to be found lying within the first. It is not, however, very highly developed, but consists of a single small free rounded strand. This central strand fuses with the margin of each of the lacunae in the first internal cylinder, but usually separates off again after a little while. In fact, it behaves towards the first internal vascular system in exactly the same way as the internal vascular strand of Dicksonia rubiginosa behaves to the ordinary stelar cylinder. 1 Pteris elata , var. Karsteniana , Kz., a variety not mentioned by Hooker, was the plant actually investigated. Anatomy of Solenostelic Ferns . 703 More rarely, it is not the central strand itself that goes to fuse with the margin of the lacunae, but a branch given off from it ; in which case it terminates there and does not separate off again. Even in rhizomes of medium size indica- tions of this second internal system are not wanting, for it is often to be observed that one of the margins of the lacunae in the first internal vascular cylinder is considerably thickened, and projects inwards in a manner similar to the margins of the leaf-gaps in the solenostele of Dicksonia adiantoides . The solenostele at the base of the lateral shoots (which arise from about the middle of the back of the petiolar strand, and not from its margin) is perfectly typical and without any internal strands. I have no doubt that a series of stages intermediate between this and the complex structures described above are to be found in weak rhizomes, or, at any rate, in the young plant. Judging from the description given by Seward 1 the vascular system of Matonia pectinata seems to be essentially similar to that of Pteris elata , both as regards the arrangement of the internal accessory strands, and also in their relation to the leaf-insertion. Miss Wigglesworth’s 2 account of the same plant serves to strengthen this opinion, although it appears that in her specimen the complexity of the internal systems is carried a step further still. For the third and most central system, which in Pteris elata consists of a small rounded strand only, is represented by a large gutter-shaped strand, or even by a completely closed cylinder. From the description of Dicksonia Plumieri ( Saccoloma adiantoides , Sw.) given by Mettenius 3 it is clear that in this plant again the vascular system is constructed upon exactly the same plan, and, moreover, it appears that a still higher degree of complexity is reached than in the Matonia of 1 The Structure and Affinities of Matonia pectinata , Phil. Trans. Roy. Soc., Lond., Series B, vol. cxci, p. 171, 1899. 3 Notes on the rhizome of Matonia pectinata , The New Phytologist, vol. i, no. vii, p. 157, 1902. 3 1. c., p. 531. 704 Gwynne- Vaughan. — Observations on the Miss Wigglesworth. For not only are there two concentric vascular cylinders lying within the ordinary solenostele, but a small central strand is present in addition, which may be regarded as an indication of a third. It is evident that in all these cases the ordinary typical vascular cylinder is represented by the outermost vascular system. The internal vascular system is an accessory de- velopment, and from the consideration of the facts brought forward above it appears that, even in its most complex form, it is to be derived from the ordinary stelar cylinder by the progressive elaboration of a local thickening of the xylem- ring at the leaf-gap margin. The initial stage of such a development would be a simple marginal thickening some- thing like that in Dicksonia apiifolia. The first step in advance would be the further development of this thickening into an internal ridge resembling that in Dicksonia adiantoides. Very little is wanting to separate off this ridge so as to give rise to a free internal strand similar to those in Dicksonia rubiginosa. The internal strand might then become converted into a more or less closed cylinder, like that found in Pteris data , in two different ways : either by enlarging and at the same time curving round so that its two ends eventually meet, or as it enlarged it might also branch, and the branches eventually fuse up into a ring. It is difficult to decide which of these two methods is the more probable, indeed, it is possible that both may occur. If the same series of changes were to take place in the first internal ring a second would be produced, and thus again a third, one lying within the other, as exemplified by Pteris data and Matonia pectinata. It must at once be understood that the order in which these Ferns have been placed in order to illustrate this theory is not intended to represent a phylogenetic series. All that it is necessary to assume is that their relationship is sufficiently close for the various modifications of structure that they present to be taken in explanation of one another. According to the theory outlined above a strong distinction must be drawn between the internal vascular cylinders and the original Anatomy of Solenostelic Ferns . 705 external one, because the former are not only different in origin, but also later in development. In this it differs essentially from the suggestion put forward by Seward 1 and Boodle 2 , according to which it would appear that the internal vascular cylinder was split off as a whole from the original solenostele. It is to be regretted that young plants of none of these Ferns were available for examination, for no doubt they would provide much valuable information upon this question. The Cyatheaceae. The first observations upon the anatomy of this order were made about a hundred years ago by Plumier, who describes the appearance of the cut end of a stem of a Cyathea . The history of the subsequent attempts to arrive at a more satisfactory knowledge of their structure is unusually inte- resting, in that it discloses how the successive results were damaged and impeded by the interference of preconceived ideas based upon currently accepted theories. For instance, it is evident that the opinions held by most of the earlier anatomists upon the nature of the Fern stem in general were really the outcome of a statement made by Cesalpino so long ago as 1583 3 . Having first come to the conclusion that Ferns do not possess true seeds, Cesalpino proceeded to deduce the fact that they cannot possess true stems either. Hence, in the earlier part of the last century, we find that Brisseau-Mirbel 4 , Link 5 and Hanstein 6 all firmly refuse to recognize a true stem in the Ferns, insisting that their caudex is merely a sympodium of leaf-bases. Indeed, the authority of Cesalpino does not seem to have lost all its influence even 1 The structure and affinities of Matonia pectinata, Phil. Trans. Roy. Soc. Lond., Series B, vol. cxci, p. 180, 1899. 2 On the anatomy of the Gleicheniaceae, 1. c., p. 739. 3 De plantis, lib. I, cap. 14. 4 Elemens de botanique, vol. i, p. 122, 1815. 5 Einige Bemerkungen fiber den inneren Bau der holzigen Farnkrauter, Linnaea, p. 414, 1826 ; also, Uber den Bau der Farnkrauter, Abhandl. d. K. Acad. d. Wissensch. z. Berlin, p. 375, 1834, an however, was entirely unaffected by it, and was the first to declare that even the central strands of the stem were cauline, although he admits that branches are given off from them which run out into the centre of the petiole. The Monocotyledonous comparison was also rejected by Mettenius 2 , although he still describes the central strands of the stem as running out direct into the petiole, sending branches to the margin of the leaf- gap as they pass through. The point was carefully reinvestigated by Trecul 3 in 1869, who reverts to the opinion of Stenzel, and concludes that none of the central strands of the stem pass out as such into the petiole, and that therefore all the vascular bundles of the leaf-scar arise from the margin of the leaf-gap. De Bary, in his text-book (1. c., p. 291), follows Mettenius, so that the question may be regarded as still an open one. Cyathea Brunonis , a Tree-fern with comparatively simple once-pinnate leaves, was examined by me, and will serve as a good example in which to describe the relations that exist between the internal accessory strands and the leaf-traces. In this plant the ordinary stelar cylinder is a dictyostele consisting of two or three large band-shaped meristeles separated by relatively small leaf-gaps. A large number of separate leaf-traces arise from the outwardly turned margin of each leaf-gap, and these are so arranged in the petiole that a figure is produced in transverse section easily recognizable as a modification of the outline given by the gutter-shaped trace so often met with in Fern petioles. In this case, however, the margins of the gutter are strongly curved towards within, and there is also a deep tuck or fold along each of its sides (Fig. 15). In consequence of this, certain of the petiolar strands come to lie some distance within the others, and these are the central strands, the origin and 1 Uber Verjiingungserscheinungen bei den Farnen, Verhandl. d. Deutsch. Acad, d. Naturforsch., Bd. xxviii, p. 18, 1861. 3 l.c., p. 525* 3 Remarques sur la position des trachees dans les Fougeres, Ann. des Sc. Nat., 5® ser., yoI. xii, p. 274, 1869. 7 o8 Gwynne- Vaughan — Observations on the course of which is under dispute. To return to the stem ; the internal strands are small and round, and about twenty or thirty of them are scattered in the ground-tissue within the ordinary stelar cylinder. At each leaf-insertion four of them approach the margin of the leaf-gap and join on to it exactly at the points of departure of certain of the leaf-traces (Figs. 15 and 16). The first pair join on to the traces a, a, the next pair divide each into two branches, which join on to the traces b, b and c, c, respectively. In their course from the leaf-gap margin down the stem the internal strands run first of all towards the centre, and then, turning more directly downwards, they travel obliquely towards without, diminishing as they do so, and finally ending blindly without coming into contact with the external stelar cylinder. The leaf-trace protoxylems are all endarch, but they gradually become mesarch as they pass down the stem ; those of the leaf-traces that abut upon internal strands are continued down the internal strands ; those of the others run down the margin of the leaf-gap, joining on to each other as they do so, and rapidly disappearing after the leaf- gap has closed. In other species (C. arbor ea and C. glauca) Tr^cul has shown that matters are much more complicated and obscure, because the number of internal steles related to each leaf-insertion is greater, and those leaf-traces that abut upon the internal strands often stand away from the leaf-gap margin, remaining connected with it only by a short horizontal strand, or they may even be altogether free from it. Considerable light is thrown upon the nature of the central strands of the petiole by the structure of Dicksonia Baro- metz. There are no internal vascular strands at all in the stem of this Fern, but only the ordinary stelar cylinder. The leaf-gaps are very small and close up rapidly, neverthe- less they occasionally overlap each other, and therefore the structure must be regarded as dictyostelic, although it is very near solenostely. The leaf-trace departs as a single piece, but sooner or later it breaks up into a large number of separate strands. The point at which the disintegration Anatomy of Solenostelic Ferns. 709 takes place varies from one leaf to another ; sometimes it breaks up almost immediately upon its departure from the stelar cylinder of the stem, and sometimes not until it has reached the free petiole (Fig. 17). While the leaf-trace remains a single continuous strand it has the form of a gutter with deeply incurved margins and a fold along each of its sides. After it has become broken up into separate portions these still keep the same conformation, so that some of the strands, chiefly those of the incurved margins, come to occupy a central position exactly as they do in Cyathea Brunonis. In this case, however, all the separate strands clearly arise from the leaf-gap margin, and from the leaf-gap margin only. It may be mentioned in passing that lateral shoots are of frequent occurrence in Dicksonia Barometz , and like those of Pteris elata they arise not from the margin but from the back of the leaf-trace, just before it begins to break up. Sometimes two may arise upon the same petiole. These observations all tend to prove that Trecul was quite correct in maintaining that the internal strands of the stem are strictly and essentially cauline, and this being granted, the idea is at once suggested that they are essentially similar in nature and origin to those of Dicksonia rubiginosa i Pteris elata y &c. It will be seen that this suggestion receives strong support from the manner in which the internal strands first appear in the young plant of Alsophila excelsa. I have been able to examine a number of young plants of Alsophila excelsa that were grown from the spore, and since the vascular system of the young plant of the Cyatheaceae has not yet been dealt with in detail, it is perhaps advisable to describe their structure at some length. Although the course of the development of the vascular system was practically the same in all the specimens examined, yet the rapidity with which the different stages are passed through varies considerably according to the conditions of growth. It must be understood, therefore, that the description given here is a more or less generalized one, and that it must not 710 Gwynne- Vaughan. — Observations on the be expected to hold good rigidly from leaf to leaf in every specimen. This statement applies in particular to the diagram given in illustration (Fig. 18). With this reservation, however, it is believed that the diagram will serve to represent the course of development of the vascular system, not only in the Cyatheaceae, but also in most of the solenostelic and dictyo- stelic Ferns up to the particular stage that they retain when mature. The young plant of Alsophila excelsa has its leaves ar- ranged radially all round the axis, and it probably grew erect. At the very base of the stem the single central cylinder possesses a small central strand of xylem, usually with a few xylem-parenchyma cells intervening between the tracheides. The first leaf-trace may depart without in any way altering the structure of this stele or of its xylem-strand, but usually the phloem on the adaxial surface of the leaf-trace is prolonged a short distance downwards into the substance of the central xylem. At the departure of the subsequent leaves this feature is much more pronounced, and the phloem thus decurrent runs down through the whole length of the internode to meet with that decurrent from the leaf below. In the second leaf, however, it often falls short of the point of departure of the first leaf and ends blindly in the internode. From this point, therefore, up to the third or fourth leaf the centre of the xylem-strand is occupied by a core of phloem. At the de- parture of about the third or fourth leaf the pericycle follows the phloem down into the internode below, so that a few pericyclic cells are now to be found in the centre of the core of phloem. At the fifth leaf (or sometimes at the fourth) the endodermis also is decurrent, giving rise at first to a few cells only in the centre of the pericycle which usually disappear before the node below is reached. Higher up it is continuous from node to node, and surrounds a progressively increasing amount of ground-tissue which is now decurrent with it. The vascular system has, in fact, at length become a solenostele. This stage, however, does not last long, for the leaf-gaps begin to overlap after the departure of about the eighth leaf. Anatomy of Solenostelic Ferns . 71 1 and above this point it becomes more and more dictyostelic, although at first a complete vascular ring is occasionally to be met with. The leaf-trace of the first five or six leaves consists of a single curved strand. Above this point two or three separate strands are given off to each leaf, and at about the tenth leaf four such strands are present, two arising from each side of the leaf-gap. The first indication of internal steles that occur in the mature plant is to be found at about the tenth leaf. Just below one or both of the two upper (adaxial) traces of this leaf the xylem of the stem-stele is seen to project slightly towards within, so as to form a small ridge on its internal surface, which is often continued as such for some distance down the stem. Some- times, however, it separates off completely so as to produce a small xylem-strand lying free within the phloem of the stele, which either ends blindly below, or eventually fuses up again with the main xylem-strand. These free xylem-strands are always present at the subsequent leaf-gaps, and although still remaining enclosed by the same endodermis, they become more and more distinct from the main xylem-strand of the stele. Later on they may even separate off from the stele altogether in the upper part of their course, only fusing with it again at a point lower down. The separation of the small xylem-strands from the main stele finally becomes complete throughout, and from their starting-point they run as small independent vascular strands ending blindly in the central ground-tissue, having no further communication with the main stele, except sometimes by a small branch near their point of origin. It seemsj therefore, that the internal vascular strands of Alsophila excelsa owe their existence to the same initial- phenomena as do those of Dicksonia rubiginosa . That is to say, they are probably derived from the elaboration of a local thickening of the xylem-ring at the margins of the leaf-gaps in the ordinary stelar cylinder. The earlier stages of their development also proceed along essentially the same lines, although it is to be admitted that there are certain marked 3 c 712 Gwynne- Vaughan. — Observations on the differences. Thus in Alsophila excelsa the internal strands of one leaf-gap are not related to any of the other leaf-gaps, nor are the internal strands of succeeding leaf-gaps in any way joined up or connected with one another. It should also be noted that in this plant the internal strands do not appear at all until the ordinary stelar cylinder has become more or less dictyostelic. The real nature of the accessory cortical strands that occur in certain Cyatheaceae ( Cyathea arbor e a, Alsophila armata , &c.) is not as yet known with certainty. Two concentric rings of vascular strands are also present in the stems of Acrosticum scandens and A. tenuifolium (. Lomaria fraxini - folia). According to Bertrand and Cornaille 1 the leaf-traces arise from both of these two rings, but which of the two is to be regarded as the typical stelar cylinder has not yet been decided. In the stem of Davallia immersa , again, two concentric series of vascular strands are present. The central ring alone gives off the leaf-traces, and probably represents the typical stelar cylinder. My material was not sufficient to determine the nature of the small peripheral strands. It is possible, however, that they are merely root-steles that run forwards for a long distance in the ground-tissue of the stem before turning outwards. Davallia aculeata and D. pinnata. The stem of Davallia aculeata , like those of the other solenostelic Davallias, is a dorsiventral rhizome with the leaves inserted in two rows upon the upper surface, but the soleno- stele itself differs so much in structure from those already described that it deserves especial mention. Instead of sur- rounding a central mass of ground-tissue as a hollow vascular cylinder, the wall of which is of the same breadth throughout as in the previous examples, the ventral region of the soleno- 1 Jitude sur quelques caracteristiques de la structure des Filicides actuelles. Memoires de l’Universitd de Lille, tom. x, no. 29, p. 136, 1902. Anatomy of Solenostelic Ferns . 713 stele in D. aculeata is more than twice as broad as the dorsal region. In consequence of this the enclosed ground-tissue is displaced so as to occupy an excentric position near the dorsal surface (Fig. 19). The extra breadth of the ventral half of the solenostele is entirely due to the increased amount of xylem present in that region, because the sheath of phloem and pericycle is of approximately even thickness through- out, both on the inside and on the outside of the stele (Fig. 20). No definite protophloem is to be made out on the inside of the stele, although it forms a fairly distinct layer on the outside. The absence of an internal proto- phloem is, however, sometimes to be observed even in typical solenosteles, e. g. Lindsaya retusa. The leaf-trace departs from the narrow dorsal region of the solenostele as a single curved strand with its concavity directed toward the median dorsiventral plane of the rhizome. In passing outwards it gradually loses its curvature, and in the free petiole has the form of an equilateral triangle with rounded angles and sides ; the xylem-strand, however, still remains V-shaped. The leaf-gap is very small and is closed up at the same time as the acroscopic margin of the leaf-trace is set free. In Davallia pinnata the habit of the stem and the insertion of the leaves is exactly the same as in D. aculeata. The appear- ance presented by the vascular system also, at least in sections taken just below a leaf-insertion, is very similar in both. It has at these points the form of a hollow vascular cylinder, the wall of which is very much broader in the ventral region than it is in the dorsal, and the ground-tissue enclosed within the stele is displaced, as in D. aculeata , so as to lie excentrically near the dorsal side (Fig. 21). On the other hand, the extra breadth of the ventral half of the vascular ring in D. pinnata is not entirely due to the xylem alone as it was in D. aculeata. The internal phloem also takes part in its production, there being a much greater quantity of this tissue on the ventral side of the enclosed ground-tissue than on the dorsal (Fig. 22). The anatomy of this plant has already been described by 3 C 2 714 Gwynne- Vaughan.— Observations on the Tansley and Lulham 1 , and the following observations confirm their account. The leaf-trace departs as a single strongly curved strand with the concavity, as usual, facing towards the median dorsiventral plane of the rhizome. The leaf-gap closes up at the same time as, or even slightly before, the leaf- trace is quite free. The sclerenchymatous ground-tissue lying in the concavity of the leaf-trace passes down with it into the substance of the stem-stele. In this manner it produces the leaf-gap itself, and also accounts for the stout strand of sclerenchyma, surrounded by endodermis and pericycle, that lies within the stele, near its dorsal side, in regions just below the nodes. If the strand of ground-tissue thus enclosed be followed downwards through the internode to the node below, it is seen to diminish gradually in size until finally it dis- appears altogether, usually a short distance before the leaf- gap next below is reached. So that in the lower part of each internode the whole space within the xylem is occupied by internal phloem alone (Fig. 21 ). Occasionally, however, the strand of ground-tissue may persist until that decurrent through the leaf-gap next below is also enclosed in the stele. In the specimens examined the ground-tissue decurrent through one leaf-gap was never found to be continuous with that decurrent through the gap below. Just before it disappears the enclosed strand sometimes breaks up into two or three small branches. The line of delimitation between the internal phloem and the xylem is not quite an even one, because small teeth of phloem project irregularly here and there between the peri- pheral elements of the xylem. The sieve-tubes of the internal phloem are unusually small and angular, and are scattered throughout the whole of its mass. They occur in greatest abundance towards the dorsal side, but no definite protophloem is to be distinguished. The stem branches frequently in a dichotomous manner. As the stele of the main axis approaches the point of branching 1 On a new type of Fern stele and its probable phylogenetic relations. Annals of Botany, vol. xvi, no. lxi, p. 157, 1902. A natomy of Solenostelic Ferns. 7 1 5 it flattens out dorsiventrally and finally divides into two by constricting in the middle. The constriction usually takes place in such a manner that there is no communication between the tissues within the xylem-ring and those without it. Some- times, however, a leaf-trace is given off at the same time as the stem-branches, and then the leaf-gap occurs just between the two branch steles and the ground-tissue is decurrent through it in the ordinary manner. The sclerenchymatous ground-tissue enclosed within the stele is always in direct continuity with that decurrent through the leaf-gaps, except a few very small strands which occasionally occur in the neighbourhood of the branchings. These strands are com- pletely surrounded by their own endodermis and appear to be quite isolated. The leaf-trace departs as a single strongly curved strand, and the curvature increases as it passes out, until sometimes the margins of the gutter meet adaxially and fuse up so as to enclose a small mass of ground-tissue (Fig. ai). This completely closed ring is only to be found over a very short distance ; it may never even be formed at all. In either case the leaf-trace eventually divides into two separate halves. Davallia repens. The peculiar nature of the vascular system of Davallia repens was first observed by Tr^cul 1 in 1885, but in his account the most interesting feature of its structure was un- fortunately overlooked. However, the same type of stele has recently been discovered in certain Lindsayas by Tansley and Lulham (l.c.), who have given it a perfectly correct inter- pretation. Davallia repens is referred to here because it is necessary to complete the series begun by D. aculeata and D. pinnata ; for the structure of its stele throughout the whole stem is similar to that found in D. pinnata at the base of the internodes only. In fact there is no ground-tissue to be found 1 Observations sur la structure du systeme vasculaire dans le genre Davallia, et en particular dans le Davallia repens. Comptes rendus, tom. ci, p. 1453, 1885. 7 1 6 Gwynne- Vaughan . — Observations on the within the stele of D. repens at any point whatever. The xylem-ring is about ten times broader in the ventral region of the stele than it is in the dorsal, and the mass of enclosed phloem occupies in consequence a very excentric position (Fig. 33). The dorsal portion of the xylem-ring is very thin and forms a kind of bridge resting on the ventral mass, and arching over the enclosed phloem. The xylem-strand of the leaf-trace departs from this bridge, giving rise to a small gap, through which the internal phloem comes into contact with the external. The endodermis and pericycle which surround the external surface of the stele are not in the least decurrent through the leaf-gap ; they pass evenly across it, or at most only dip very slightly inwards. The leaf-gap closes up before even the xylem of the leaf-trace has yet separated off from that of the stem-stele. The structure of the internal phloem is quite normal, and the whole of it is probably to be regarded as metaphloem. The sieve-tubes nearest the bridge are some- what smaller than the rest, but no definite protophloem can be distinguished, nor does the external protophloem dip in through the gap in the xylem of the bridge. The leaf-trace departs as a single strand, more or less cordate or reniform in section. The steles of Davallia tenuifolia , Parkeri \ hymenophylloides and clavata were found to be precisely similar to that of D. repens , apart from slight differences in the relative thick- ness. of the ventral mass of xylem and the dorsal bridge, and in the amount of internal phloem present. The same type of stele is also to be found in fifteen or more different species of Lindsay a, but since a paper upon the anatomy of this genus is in preparation by Tansley no further reference need be made to them here. This type of vascular system has been called the Lindsay a-type by Tansley and Lulham, and since it is so characteristic of that genus it will be referred to in this paper by the same name. It should be noted, however, that there are at least two solenostelic species of Lindsay a. One of these, Lindsay a retusa , is perfectly typical and has already been mentioned. The solenostele of the other, Anatomy of Solenostelic Ferns . 717 Lindsay a cultrata , is very small and thin, and, moreover, the leaf-trace departs as two separate strands and not as a single piece. Tansley has suggested that the two types of stele exhibited by Davallia repens and D. pinnata represent structures inter- mediate between protostely and dictyostely. I thoroughly agree with this, and consider that the type of stele found in D. aculeata may now be added to this series. The almost exactly parallel stages passed through by the vascular system in the young plant, even in such an advanced dictyostelic Fern as that described on p. 710, appear to me to give the suggestion a high degree of probability. As I understand the facts, the idea is that as the leaf and the leaf-trace in- creased in importance relative to the stem, the phloem lying on the adaxial side of the leaf-trace became extended down- wards into the substance of the xylem of the protostele. Gradually reaching further down through the internode this internally decurrent phloem at length came into contact with that decurrent from the leaf-trace below, and a continuous solid core of phloem was thus formed within the stele. Then the ground-tissue lying in the adaxial concavity of the leaf- trace also began to extend downwards into the stele, forming at first a prolongation that ended blindly in the core of phloem, but eventually it reached down from one leaf-trace until it met with that decurrent from the leaf-trace below. In this manner an internal strand of ground-tissue was formed which is continuous throughout the stem, and the stele has become a solenostele. Now if such a series of changes were to take place in a dorsiventral rhizome with the leaves inserted only on the dorsal surface, it is extremely probable that the phloem and ground-tissue decurrent from the leaf-traces would not at first occupy the very centre of the stele, but would lie nearest to the dorsal surface on which the leaves are inserted, and hence the ventral portion of the xylem-ring would be broader than the dorsal, as is actually the case in Davallia repens , D. pinnata , and D. aculeata. What is not so easy to understand is why the xylem-ring should 7 1 8 Gwynne- Vaughan. — Observations on the ever become of even thickness all round in such a dorsi- ventral rhizome. Judging from the D aval lias and Lindsayas alone, it would seem that a continuous core of phloem was already present in the stele before the ground-tissue began to be decurrent at all. On the other hand, from Boodle’s 1 description of the structure of the node in certain Gleichenias ( G . dichotoma , G.flabellata), it appears that both the ground-tissue and the phloem are decurrent together and for a short distance only into the substance of the xylem. If this may be regarded as the first step in another series of modifications similar to those described above, it follows that in this case a soleno- stele could be reached without passing through a stage with a solid core of phloem, because both ground-tissue and phloem would be decurrent contemporaneously. The whole theory is, of course, open to the inevitable criticism that the series of forms in question is perhaps one of reduction, and not one of advance. It seems to me, however, that the increased thickness of the lower region of the xylem- ring forms an insuperable objection to the general application of any reduction hypothesis to this series. That the vascular system actually has undergone reduction in a number of different Ferns is well known, but although it must be admitted that in some cases structures have resulted which bear a strong superficial resemblance to those described above, it may never- theless be shown that there are crucially important differences between them. For instance, in Vittaria stipitata , which possesses a dorsiventral rhizome and leaves in two rows on its dorsal surface, the stele is very small and the xylem-ring is only one or two elements thick. Each leaf is supplied with two separate traces, one of which departs from each side of the leaf-gap, and the ground-tissue is decurrent through the leaf-gaps into the stele. So far as the stele itself is con- cerned each leaf-gap is closed up again before the next above is formed, but the gaps in the xylem-ring remain open long enough to overlap, so that in this respect the stele resembles 1 On the anatomy of the Gleicheniaceae, 1 . c., p. 720. Anatomy of Solenostelic Ferns . 719 that of Cheilanthes lendigera (cf. p. 696). At the level of the leaf-gap the internal ground-tissue is fairly voluminous, but it rapidly decreases as it passes down the internode until only a small strand is left lying close to the dorsal side of the stele. In my specimens this also eventually disappears, so that the decurrent ground-tissue is not continuous from one leaf-gap to another. The stele, therefore, in its general appearance resembles that of Davallia pinnata , but on closer comparison some very important differences come to light. In the first place the xylem-ring of Vittaria stipitata is equally narrow on all sides of the stele, and secondly, as the internal ground-tissue disappears it is not replaced by phloem but by pericycle. Only a slight amount of internal phloem is present at the most ; it is even completely wanting on the ventral side of the stele, being replaced by parenchyma. A number of plants identified as Vittaria elongata were also investigated, and in some of them the stele possessed exactly the same structure as in V. stipitata. In others the ground-tissue did not pass in through the leaf-gaps at all, so that, apart from the thin internal sheath of phloem, the whole of the centre of the stele was occupied by pericyclic parenchyma, even at the level of the leaf-gap itself. In several other specimens, again, the vascular system proved to be distinctly dictyostelic and of the simple dorsiventral type described on p. 695. According to Poirault 1 no internal phloem whatever is to be found in this species, and Jeffrey 2 states that both the internal phloem and the internal endo- dermis are wanting, but a certain amount of internal phloem was present in all the specimens that I examined, although it is replaced by parenchyma on the ventral side. It is rather surprising to find so wide a variation in the vascular anatomy of one and the same species, and since it is very difficult to be quite sure about the identification of some of the Vittarias 1 Recherches anatomiques sur les cryptogames vasculaires, Ann. des Sc. Nat., 7 e s D. tenuifolia , D. hymenophylloides , and in most of the Lindsay as with the same type of stele. They have exactly the same form and appearance as those described by Boodle 1 in Lygodium dichotomum. In Davallia repens and Lindsay a lohata they also occur in the phloem-parenchyma. The first-formed elements of the external phloem are always more or less distinct from the rest, and constitute a fairly definite protophloem. In most cases a definite protophloem is also to be found on that side of the internal phloem furthest away from the xylem, but in the Lindsay a- type of stele (Figs. 22 and 23) and also in several solenosteles, Davallia platyphylla , D. strigosa , D. hirta , Lindsay a retusa , &c., no internal protophloem can be made out at all. It has already been mentioned that internal phloem is altogether absent from the ventral side of the stele in Vittaria slipitata , Antrophyum plantagineum , A. recticulatum and A. semico - statum. The petiolar bundle of the Cyatheaceae and Polypodiaceae is essentially concentric throughout. The phloem is most plentiful on the abaxial side of the xylem, but at the same 1 On the anatomy of the Schizaeaceae, Annals of Botany, vol. xiv, no. lviii, pp. 364 and 402, 1901. 3 D 3 730 Gwynne- Vaughan. — Observations on the time it is never altogether absent from the adaxial side (Figs. 24, 25, 26). The protophloem is always quite distinct on the abaxial side, and it is nearly always to be found on the adaxial side as well. Indeed when the petiole contains a single strand only, the protophloem can often be followed all round its adaxial concavity. Whenever the xylem strand of the petiole is prolonged into a hook, the protophloem, if present, always passes straight across over the bay that lies between the hook and the main strand (Fig. 26). It appears, therefore, that the sieve-tubes situated within the bay itself must be regarded as belonging to the metaphloem. In most cases the sieve-tubes within the bay of the hook are quite normal (Figs. 25, 26), but in a good many Ferns they exhibit a special kind of structure. Their walls are unusually thick, and when unstained have a swollen pearly appearance. The additional thickening is all cellulose, and consists of two fairly distinct layers, the innermost of which is broader, softer, and less refractive than that next the middle lamella. They have rather more contents than the ordinary sieve-tubes, and the deeply staining granules characteristic of typical Fern sieve- tubes are rarely if ever to be found in them. For all that they do not seem to be essentially different from typical sieve-tubes, although it is doubtful whether they continue to function as such. One form of sieve-tube graduates insen- sibly into the other ; indeed, towards the base of the petiole the thick-walled sieve-tubes are nearly always replaced by the typical form. The thickened sieve-tubes may also occur all round the adaxial side of the leaf-trace ; especially near the protoxylems, and again on the abaxial side of the strand on the flanks of the xylem. They are especially well shown in the petioles of Dicksonia adiantoides, D. culcita , D. puncti- lofra, Davallia aculeata, D. platyphylla, and D, davallioides. These modified sieve-tubes occupy exactly the same position as the lignified ‘ phloem-fibres ’ in the leaf-traces of L ox soma Cunninghamii 1 and of certain species of Aneimia 2 , and 1 Gwynne- Vaughan, 1. c., p. 83, Figs. 5 and 6. 2 Eoodle, On the anatomy of the Schizaeaceae, 1 . c., p. 400. Anatomy of Solenostelic Ferns . 731 I have no doubt that these also represent metamorphozed sieve-tubes. Attention must finally be drawn to the very remarkable mucilage ducts or vessels that are to be found in the external phloem of the petiolar strands of Dicksonia Barometz . They occur in the metaphloem, and are easily distinguished from the rest of its elements by their greater size and their dense, deeply staining mucilaginous contents. The structure of these elements was not investigated in detail, but it appears that they are formed by a number of elongated cells arranged in vertical series, the walls of which have become reabsorbed at certain points where they are contiguous, so that their con- tents are continuous throughout the series. In position they correspond to the inmost sieve-tubes of the metaphloem, but the perforations appear to be true perforations, and they are much too wide to resemble the sieve-plates. Whether they are to be regarded as metamorphozed sieve-tubes or not was not decided. From a figure given by Bertrand and Cornaille (loc. cit., p. 58, Fig. 30) similar structures appear to be present in the petiole of Dicksonia regalis. The Systematic Value of the Vascular Anatomy. No really satisfactory conclusion upon the degree of impor- tance that ought to be assigned to the vascular anatomy as a factor in the classification of the Polypodiaceae can be arrived at until the structure of at least a majority of the species of the various genera has been correctly described. The facts already at our disposal, although not so extensive as one might wish, are still sufficient to show that the characters brought to light by the study of the vascular anatomy will probably prove to be of great assistance in constructing a natural classification, and they must certainly be taken into account by the systematists. The anatomy of so many species, even in the genera especially dealt with in this paper, is still unknown, that the tentative nature of any conclusions drawn from the results obtained must, in the first place, be thoroughly understood. 73 2 Gwynne- Vaughan . — Observations on the If the solenostele and the Lindsaya-type of stele are to be regarded as the most primitive types of vascular arrangement in the Polypodiaceae, as suggested above (p. 71 7), it must at the same time be admitted that these primitive characters do not run parallel with Professor Bower’s division of the order into Gradatae and Mixtae. Bower himself, however, supports the view that several different lines of descent may be represented within the Polypodiaceae alone 1 , and it is very probable that a more or less similar primitive type of vascular arrangement might occur in the primitive members of each line of descent. It follows that those genera in which the solenostele, or the Lindsaya-type of stele, is predominant may be regarded as relatively primitive, at any rate within their own particular family. The prevalence of the primitive types of stele in the various genera and subgenera may be summed up as follows. All the species of Dennstaedtia (regarded by Hooker in the ‘ Synopsis Filicum ’ as a section of Dicksonia) that have hitherto been examined prove to be essentially solenostelic. It must be noted, however, that in D. rubiginosa the soleno- stele is not quite typical, and that additional internal vascular strands are also present. Microlepia , including Saccoloma , is placed in the ‘ Synopsis Filicum ’ among the Davallias, and, apart from the fact that additional internal vascular strands are present in the Sacco- lomas (cf. p. 703), all the species that have been examined are typically solenostelic with two exceptions only. Of the ex- ceptions, Davallia ciliata is dorsiventrally dictyostelic, and is clearly out of place among the Microlepias 2 . It is placed by 1 Bower, Studies in the morphology of spore-producing members, no. 4, Phil. Trans. Roy. Soc. London, Series B, vol. cxcii, p. 123, 1899. 2 Professor Bower has been kind enough to examine the sorus of this species for me, and he finds that ‘ the receptacle is almost flat, and the sporangia of various ages are intermixed ; successive ones being interpolated without order between those already there. The older sporangia are long stalked, so as to raise their heads above the younger. There appears to be no regularity of orientation. The annulus is vertical. All these characters stamp it as one of the Mixtae, and it should find its place elsewhere than among the Microlepias.’ Anatomy of Solenostelic Ferns. 733 J. Smith 1 in the section Leucostegia under the synonym of L. hirsuta , and this arrangement is quite in accordance with its vascular structure. The other exception is Davallia pinnata , the stele of which exhibits a structure intermediate between a solenostele and the Lindsaya- type of stele. This plant has been removed from Microlepia by H. Christ 2 and given a section to itself : Wibelia. The anatomy agrees with this separation, and indicates a closer relationship to the Lindsayas than to Microlepia. Davallia Novae-Zelandiae ( Leptolepia , Met.) is regarded by J. Smith and H. Christ as a species of Microlepia , but in the ‘ Synopsis Filicum 5 it is included in the section Leucostegia. Since, however, it proves to be typically solenostelic, and the section Leucostegia itself is a predominantly dictyostelic one, the anatomy gives un- qualified support to the two former authorities. Probably all the species of the genus Hypolepis are soleno- stelic, although the four species mentioned in this paper are the only ones in which the anatomy has been sufficiently described. Prantl 3 * , in 1892, proposed to divide the Polypodiaceae into four great tribes : the Aspidieae, the Asplenieae, the Pterideae, and the Polypodieae. At the same time he founded the sub- tribe Dennstaedtiinae to include the genera Dennstaedtia. Microlepia , Leptolepia , Saccoloma and Hypolepis , which he regards as containing all the most primitive species of his first tribe, the Aspidieae. It has been shown above that essentially the same type of primitive vascular system is to be found in every species of this sub-tribe in which the anatomy is known. Therefore, as regards the primitive nature of the sub-tribe as a whole, Prantl receives strong support from the anatomy, but to decide whether all these genera belong to the base of one and the same line of descent, or not, is another and a very difficult question ; as he himself acknowledges. Dennstaedtia and Microlepia certainly appear 1 Historia Filicum, 1875. 2 Die Farnkrauter der Erde. Jena, 1897. 3 Das System der Fame, Arbeiten aus dem K. Bot. Gart. z. Breslau, Bd. i, Heft i, 1892. 734 G wynne- Vaughan. — Observations on the to go together, and they both come under Bower’s division of Gradatae. It seems probable also that the genus Loxsoma should be regarded as more nearly allied to these two genera than to any others. The development of the sorus in Lepto - lepia and Saccoloma is not known, but Hypolepis belongs to the Mixtae. According to the anatomy Leptolepia goes with the Microlepias, but it may prove that a distinction should be made between Saccoloma and Hypolepis and the rest of the group, and also between each other. As a secondary charac- ter of the Dennstaedtiinae Prantl states that, except in Sacco- loma , hairs are present instead of paleae throughout the group. So far as the species that I examined are concerned this certainly holds true. The Lindsaya- type of primitive stele has been found in all the species of that order hitherto examined, except in L. retusa and L. cultrata , which possess solenosteles. The same type of stele is also characteristic of the sections Odontoloma and Stenoloma , which are placed by Hooker in the genus Davallia. The anatomy, therefore, agrees with H. Christ in removing these two groups from Davallia and placing them among the Lindsayas. J. Smith also places Odontoloma in his tribe Lindsaeeae. The section Stenolojna he removes from the Davallias, but places it in his tribe Saccolomeae under the synonym of Odontosoria. It should be mentioned that Davallia ( Stenoloma :) aculeata is somewhat exceptional, in that it exhibits a type of solenostely peculiar to itself. H. Christ has given it a section of its own : Lindsayopsis. It has already been stated that according to the anatomy Davallia {Microlepia) pimiata should be included with the Lindsayas rather than with the Microlepias. The most primitive genera in Prantl’s second tribe, the Asplenieae, were considered by him to be Lindsaya , Lindsayopsis , Wibelia {Davallia pinnata), Odontosoria {Stenoloma) and Davallia. If the last genus, Davallia , be excluded he finds here again support from the anatomy, since all the species in the four remaining genera possess a primitive vascular system, and, with three exceptions only, they all possess the same type of stele. Finally they all Anatomy of Solenostelic Ferns. 735 belong to Bower’s division of Mixtae. The presence of paleae instead of hairs is given by Prantl as a secondary character- istic of this group, and it held good in all the examples examined by me. Of the genus Davallia there now remain to be discussed the sections Humata, Endavallia , Leucostegia and Loxoscaphe . All the species that were examined in these sections proved to be perfectly dictyostelic, with the single above-mentioned exception of Davallia ( Leucostegia :) Novae-Zelandiae. The vascular arrangement was dorsiventral in every case, except Davallia Emersoni and D. contigua which are radially sym- metric. These two species form the sub-section Prosaptia , which, according to J. Smith, should be removed from the Davallias altogether. Upon the whole the anatomy of the above sections would agree better with the Polypodi than with the rest of the genus Davallia. Only a few species of Pteris are known to be solenostelic. One of these, P. incisa , is isolated with its varieties as the section Histiopteris both by Smith and H. Christ. Another, P. scabenda , together with P. viscosa , the anatomy of which is as yet unknown, form, according to Christ, the separate section Paesia. Jamesonia is solenostelic, and so also are two species of Pellaea. All these belong to Prantl’s third tribe, the Pterideae, the most primitive genera of which he considers to be Lonchitis , Pteridium , and Paesia . It appears, therefore, that the agreement of the anatomy with his arrangement is not so complete in this as in the two previous tribes. In his fourth tribe, the Polypodieae, solenosteles are still more rare. It is true that the Polypodiums of the section Dipteris are solenostelic, but Seward and Dale 1 have shown that it must be removed from the Polypodiums altogether. They even go so far as to give it a family to itself, apart from the Polypodiaceae. The only other case of solenostely that I am aware of in this group is in Polypodium punctatum , and here the vascular system so very closely resembles that of Hypolepis that, since Hooker himself has remarked that this 1 On the structure and affinities of Dipteris, 1 . c., p. 502. 736 Gw y nne- Vaughan, — Observations on the plant (1. c. p. 312) ‘is very closely related to Euhypolepisl it may confidently be removed to that genus. Upon the whole, therefore, Prantl receives considerable support from our results, since nearly all of the genera re- garded by him as relatively primitive in their respective family branches also prove to be characterized by the possession of a primitive vascular structure, especially as regards his first two tribes. Nevertheless, this must not be taken to mean that each, or even any, of his tribes actually represent separate single lines of descent. Much further research is necessary on all sides before this question can be satisfactorily faced, and the above discussion merely serves to point out the fact that anatomical considerations must play an important part in coming to any conclusion. Conclusion. The stelar theory has undergone many modifications under the hands of different authors since it was first introduced by Van Tieghem, and the exact meaning of the word ‘ stele * as now used is getting somewhat obscure. It is, however, becoming more and more apparent that the chief value of the conception lies in its ontogenetic and phylogenetic significance, whereby the stele of the stem may be regarded as the central cylinder of the young plant and all those tissues of the mature axis that result from its modification, or, as Farmer and Hill 1 would prefer to have it, the central cylinder of the young plant and all those vascular tissues of the mature axis that result from its modification. As a consequence of the first point of view it must also be held that there exists a regional distinction of primary importance between the stelar tissue and the cortex. Therefore, when considering a vascular arrangement such as a dictyostele or a solenostele it becomes impossible to neglect the question, whether the central paren- chyma is to be regarded as stelar, and therefore morphologi- 1 On the arrangement and structure of the vascular strands in Angiopteris evecta and some other Marattiaceae, Annals of Botany, vol. xvi, no. 62, p. 392, 1892. Anatomy of Solenostelic Ferns. 737 cally distinct from the cortex ; or as cortical, in which case the stele, or the separate portions of it, must possess a definite internal as well as an external limit. Supposing the central parenchyma in question to be really stelar, then it must have come into existence by the substitution in the stele of paren- chymatous elements for those that were previously vascular. To take the case of the Cyatheaceae and Polypodiaceae in particular ; if the course of development actually did take place in the manner suggested above (p. 717), then each cell of the central parenchyma must have belonged in previous generations successively to the xylem, phloem, pericycle and endodermis before attaining its present condition. On the other hand, if the central parenchyma be regarded as cortical, then the stelar elements at certain points in the stele through successive previous generations must have undergone fewer and fewer divisions as they developed, while the divisions in the cortex opposite these points must have correspondingly increased. Therefore the cortical tissue at these points would eventually encroach upon the vascular, and would in time come to occupy the greater part of the centre of the stele. It has been very generally assumed that if the distinction between stele and cortex is really a morphological one, the two regions must of necessity be marked off from one another by the earliest cell-divisions at the apex, or by the so-called histogenetic layers. But recent researches upon apical meri- stems 1 have shown that the earlier tangential divisions in the segments of an apical cell, and even the histogenetic layers of Hanstein, are not only very inconstant and unreliable, but also that they bear no invariably fixed relations to any of the subsequent tissue-differentiations in the mature regions of the plant, and that in consequence they have little or no general value as morphological criteria. It does not appear to me that the regional significance of the stele is in any way bound up with the maintenance of these distinctions. The con- sideration of the morphology of the stele can only begin when 1 Schoute, Die Stelartheorie, Groningen, 1902 : also Tansley, Proceedings of the Linnean Society, Nov. 20, 1902. 738 Gwynne- Vaughan. — Observations on the that region is definitely and satisfactorily delimited. It is not directly concerned with any question as to which particular segment it is in which the tangential wall appears that first of all delimits it. All that is required is that a definite delimitation should actually be possible at one point or another during the course of its development in a majority of cases sufficiently great to render the statement general. According to the view taken by Farmer and Hill the attention is concentrated upon the vascular tissue alone, and therefore the stele as a whole is deprived of any regional distinction. I quite agree with them that it is inconvenient, from a descriptive point of view, to draw theoretical distinc- tions that have no histological expression between different regions of the general ground-tissue. But at the same time I hold that it would be a great mistake to give up all attempts to discover the phylogenetic history, and the precise method of origin, in each particular case of such tissues as the central parenchyma, and even as the much abused en- dodermis. Full information upon such points is bound to be of considerable value, and the ability to state of two plants presenting the same type of structure whether they reached this condition by passing through the same, or through different series of changes would throw light upon many interesting problems which might otherwise remain obscure. For instance, in the Cyatheaceae and Polypodiaceae, it has been suggested above that, whether by the intrusion of the cortex, or by the metamorphosis of stelar tissue, the first appearance of the internal parenchyma must have taken place at the periphery of the protostele, and at points just above the departure of the leaf-traces. This displacement, or trans- formation, of the vascular tissue then advanced gradually inwards from these points until even the most central region of the stele was affected by it. The internal parenchyma, therefore, from the moment of its first appearance, was always in contact with the cortical parenchyma. Now several other methods of procedure might also have taken place by which a similar result could be attained. For Anatomy of Solenostelic Ferns. 739 instance, the first appearance of internal parenchyma might take place in the centre of the xylem of the protostele. The xylem-ring thus formed might subsequently become interrupted by the departure of the leaf-traces, and finally a structure resembling a solenostele might be attained by the gradual differentiation of phloem and endodermis through the leaf-gaps and all round the inside of the xylem-ring. Again, an internal endodermis might be differentiated within the internal paren- chyma before the xylem-ring is interrupted, in which case the phloem alone would have to extend around the inside in order to bring about the above-mentioned structure. Finally, the internal phloem and endodermis might both be dif- ferentiated within the internal parenchyma before ever the xylem-ring is interrupted, and then the formation of leaf-gaps would do no more than set the internal tissues in continuity with the external. Although the first of these methods alone has been ascribed to the Cyatheaceae and Polypodiaceae above, it is very probable that the others may occur in other orders. Indeed Boodle 1 has already made some suggestions on similar lines in relation to the Schizaeaceae. In a vascular system arising according to the two last methods it is evident that there can be no two opinions regarding the stelar origin of the central parenchyma. In the first two cases, however, it is possible to conceive of the intrusion of the cortex into the stele in the manner previously explained. It is difficult to see where any conclusive evidence upon this point, one way or another, is to be sought for. It is, however, reasonable to suppose that if the young plant of such a Fern as Davallia pinnata be examined at different stages in its development, some light may be thrown on the matter by the comparison of the state of affairs at those regions of the apex where the distinction between stele and cortex first becomes evident : or, perhaps, even by the comparison of the same region in the mature plant with that in a typically solenostelic Fern. 1 On the anatomy of the Schizaeaceae, 1 . c., p. 407, and Further observations on Schizaea, Annals of Botany, vol. xvii, no. lxvii, p. 530, 1903. 740 Gwynne- Vaughan. — Observations on the The simplest way of getting over the matter would be to accept the stelar origin of the central parenchyma in all cases, and to regard the internal endodermis as never strictly homologous with the outer. But still the other alternative is theoretically possible, and should not at once be rejected as inherently improbable. In conclusion I have to thank Professor Bower and Dr. Lang for the assistance they have given me in obtaining material, and for their valuable advice upon various points in relation to my work. I have further to express my gratitude to the Director of the Royal Gardens, Kew, the Director of the Royal Gardens, Calcutta, and to Mr. Hemsley of Darjeeling, for their kindness in providing me with much useful and valuable material. Anatomy of Solenostelic Ferns. 74i EXPLANATION OF FIGURES IN PLATES XXXIII, XXXIV, AND XXXV. Illustrating Mr. G Wynne- Vaughan’s Paper on Solenostelic Ferns. Figs. 12, 20, and 22 to 28 are from photographs; a more or less under-exposed print being used as a camera-lucida drawing. All the other figures, except Fig. 29, are diagrams. Fig. 29 was drawn from the section. The following lettering is used throughout ; L. T., leaf-trace ; e ., external endodermis ; e'., internal endodermis ; P., external pericycle; P., internal pericycle ; ph., external phloem; ph! ., internal phloem ; pph ., external protophloem ; ppti internal protophloem ; prx., protoxylem. Fig. 1. Dicksonia punctiloba. Diagram of vascular system of rhizome including a node and the base of a leaf-trace. The upper surface of the rhizome would face the observer. Fig. 2. Dicksonia apiifolia. Ditto. Fig. 3. Davallia Speluncae. Ditto. Fig. 4. Hypolepis millifolia. Ditto: l.sh., lateral shoot arising from basiscopic margin of leaf-trace ; a ., vascular strand running from free margin of lateral shoot to proximal margin of leaf-trace ; b., a similar strand running to distal margin of leaf-trace. Fig. 5. Hypolepis tenuifolia. Ditto : l.sh. and a. as in Fig. 4 ; c., vascular strand running from free margin of leaf-gap to acroscopjc margin of leaf-trace. Fig. 6. Hypolepis repens. Ditto : l.sh., a. and b. as in Fig. 4 ; l.sh'., lateral shoot arising from acroscopic margin of leaf-trace. Fig. 7. Nothochlaena Marantae. Diagram of vascular system of rhizome including two nodes and the bases of the departing leaf-traces. The upper surface of the rhizome faces obliquely towards the top of the plate. Fig. 8. Pellaea rotundifolia. Ditto. Fig. 9. Gymnogramme calamelanos. Ditto. The stem is radial. Fig. 10. Plagiogyria biserrata. Diagram of transverse section of the vascular system. The steles are unshaded ; the dark masses sc.e. and sea. represent sclerenchyma respectively external and internal to the stelar ring. Fig. 11. Dicksonia adiantoides. Diagram of \ascular system of rhizome, including a node and the base of a leaf-trace : l.sh., lateral shoot arising from basi- scopic margin of leaf-trace ; i.s., ridge upon internal surface of solenostele. The upper surface of rhizome would face the observer. Fig. 12. Dicksonia adiantoides . Transverse section of the free margin of a leaf- gap in the solenostele : i.s., the free xylem-strand forming a projection on the internal surface. Fig. 13. Dicksonia rubiginosa. Diagram of the vascular system of the rhizome including a node and the base of a leaf-trace : l.sh. and i.s. as in Fig. 11 ; lacunae in the solenostele not related to the departure of a leaf-trace. The upper surface of the rhizome would face the observer. 742 G wynne- Vaughan. — On Solenostelic Ferns. Fig. 14. Pteris data , v. Karsteniana. Ditto. A piece is supposed to be cut out of the side of the solenostele so as to show the internal vascular system. Note that a small strand lying within the second vascular ring is also present. The stem is radial. Fig. 15. Cyathea Brunonis. Diagram showing the arrangement of the vascular strands in the petiole : a ., b. and c. indicate those below which the internal vascular strands of the stem are inserted. Fig. 16. Cyathea Brunonis. Diagram of one side of the acroscopic half of a leaf-gap ; seen from within, and showing the insertion of the internal strands of the stem, a ., b. and c. Fig. 17. Dicksonia Barometz. Portion of the vascular system of the stem; seen from within, and showing the departure of three leaf-traces. Fig. 18. Alsophila excelsa. Diagram of vascular system of a young plant in median longitudinal section. The xylem is black, the phloem lightly shaded and the endodermis is indicated by a dotted line. The ground-tissue is left white. Fig. 19. Davallia aculeata. Diagram of vascular system of rhizome including a node and the base of a leaf-trace : ph! ., internal phloem. The external phloem is not indicated. The upper surface of the rhizome would face the observer. Fig. 20. Davallia aculeata. Transverse section of the stele of the rhizome in the middle of an internode : scl'., sclerenchymatous internal ground-tissue. Fig. 21. Davallia pinnata. Diagram as in Fig. 19. The vascular system is supposed to be curved so that the two cut ends face the observer more or less obliquely: ph'., internal phloem. Fig. 22. Davallia pinnata. Transverse section of the stele of the rhizome in the upper part of an internode : scl. and scl'. , sclerenchyma belonging respectively to the external and internal ground-tissue. Fig. 23. Davallia repens. Transverse section of the stele of the rhizome at a point immediately above the leaf-gap. The petiolar bundle has not yet become free. Fig. 24. Davallia repens. Transverse section of the vascular bundle of the free petiole. Fig. 25. Davallia tenuifolia. Ditto : Hk., adaxial hook of the xylem. Fig. 26. Davallia Speluncae. Ditto: Hk ., as in Fig. 25; Cp ., cavity- parenchyma. Fig. 27. Dicksonia davallioides. Portion of a transverse section of the soleno- stele : Cp., cavity-parenchyma. Fig. 28. Dicksonia apiifolia. Portion of a transverse section of the solenostele. Fig. 29. Dicksonia apiifolia. Cells of the cavity-parenchyma sending protrusions into a disintegrating protoxylem element of a young petiole. ArurvaLs of Bobouny. Fig. 5. Fig . 6 . Fig . 9 . LX. z. Fig . 10 . M.'GrV. del. xx HI! Fig .11. GWYN N E-VAUGHAN - SOLE NOS TE LI C FERNS, Voixvii,pi.miit ■ University "Press Oxfor a . AnzmLs of £obany. VoL.miPimni GWYN N E-VAUGHAN- SOLE NO S TE LIC FERNS. GWYNNE-VAUGHAN.-SOLENOSTELIC FERNS. Vol.XVHPl.XXX/V JS- l£R$X/-4W %?± JCkyt li V- )v \WVv€ ;r^ , •!'. PlYSXsffis** E&ipK-^rt xX ry-Sfil! tL 1 vyy > Tht ^ 1 Mf&g fee Wr7r University Press, Oxford. VoixviiPimii Armais of Botany GWYNNE-VAUGHAN.-SOLENOSTELIC FERNS. Jbrmxxls of Botany. Vol.XVIl PI MXV. Fig. 26. D T G-V. del Univer sityPress, Oxford. GWYNNE-VAUGHAN- SOLENOSTE1IC FERNS. 1 1 On the Genus Corynocarpus, Forst., with Descriptions of two New Species. BY W. BOTTING HEMSLEY, F.R.S., F.L.S., Keeper of the Herbarium and Library , Royal Botanic Gardens , Kew. With Plate XXXVI, and two Figures in the Text. Botanical History. ORYNOCARPUS was established by the Forsters (Char. Gen. PI. Ins. Mar. Austr., p. 33, t. 16) in 1 776, and although the description is incomplete, and the figures of the parts of the flower inaccurate, there can be no question about the tree intended. It was described from specimens collected in New Zealand on Cook’s second voyage (1773-75), and the perfect fruit seems to have been unknown to the Forsters, or they would hardly have given it a name signifying club-fruit 1 . But Sir Joseph Banks and Dr. Solander, who were the botanists on Cook’s first voyage (1768-71), also brought specimens of this tree to England, and it was described and figured by them under the ’name of Merretia lucida 2 , though not published. The authorities of the Botanical Department of the British Museum have obligingly furnished me with 1 They were evidently unaware, too, that the fruit of Corynocarpus is edible, or it would have been included in G. Forster’s * De Plantis Esculentis Insularum Oceani Australis.’ a In memory of Christopher Merrett, M.D., author of ‘Pinax rerum naturalium Britannicarum,’ 1 666. [Annals of Botany, Vol. XVII. No. LXVIII. September, 1903.] 3 E 744 Hemsley. — On the Genus Corynocarpus , Forst ., a copy of the description, which is very full and accurate in most of the details. The most important point in which it differs from what I have observed and what other authors have described, or figured, is the shape of the petaloid staminodes. They describe them as c apice tricuspidata, cuspide intermedio duplo maiore.’ As may be seen from the accompanying figures, the staminodes of C. similis and C. dissimilis are acutely toothed at the apex, whilst those of C. laevigata are irregularly and minutely toothed from about the middle upwards and around the top. There can be no doubt about Banks and Solander’s specimens having been brought from New Zealand, because exact localities are given, and because Cook did not visit the New Hebrides on his first voyage. On the second voyage he touched at several of the islands ; but the Forsters record their Corynocarpus from New Zealand, and their figures and description of the staminodes convey no information whatever beyond the presence of such bodies in the flower. Banks and Solander also describe a fully developed fruit in the following terms : ‘ Drupa oblongo-ovalis, glaberrima, lutea, magnitudine Olivae Hispanicae (ij unc.), substantia carnosa, lutea sesquilineam crassa edulis/ They further describe the ‘ nucleus ’ [seed] as ‘ amarissimus.’ Unfortunately Banks and Solander’s specimens in the British Museum only bear two imperfect flowers, and therefore it is almost, or quite, impossible to test the accuracy of their drawing and description, though there is no reason to doubt it, except the fact that the staminodes are different from those figured and described by others. Forsters’ specimens in the British Museum bear a number of flowers, and in one examined the staminodes are of the usual form of those of C. laevigata. It is quite probable, however, that there is considerable variation in this organ in all three species, as, in C. similis , they vary from three- to nine-toothed at the apex. The earliest writers, subsequent to the Forsters, attempted the classification of Corynocarpus from the description and figures of the latter. Scopoli (i 777) placed it in his ‘ Nomadeae,’ the definition of which I have not mastered. with Descriptions of two New Species . 745 Jussieu (1789), who had more definite ideas, included it in his ‘ Berberides.’ In this he was followed by St. Hilaire in 1805, and Roemer and Schultes in 1819. In 1823, according to various horticultural authorities, it was in cultivation in this country, but I have not succeeded in finding any published exact record of its introduction. I have some doubts, however, about this date being correct, because I have found evidence of its having been introduced to Kew in 1824. In the Kew collection there are three coloured drawings of barren branches of C. laevigata. The earliest is dated Feb. 1825, and is endorsed as having been made from a living plant sent by Mr. Allan Cunningham from New South Wales in 3 824, and a reference is given to the page of the ‘ inwards book J of that date, where it is recorded that the plant was dispatched from New South Wales in February, and received at Kew in June, 3824. There is also a record of another living plant having been received from the same source in 1 830. In 1832 A. Richard (Voyage de lAstrolabe ; Essai d’une Flore de la Nouvelle Zelande, p. 365) gave a somewhat fuller description of the genus, f e manuscr. Forst./ but he adds nothing of importance. He places it under ‘ Genera incertae sedis vel quoad ordines dubia.’ G. Don, 1837 (Gen. Syst. iv, p. 23) appears to have examined specimens, and refers the genus to the Myrsinaceae. He also mentions that it had been in cultivation since 1823. A. Cunningham, in 3 840 (Florae Insularum Novae Zelandiae Precursor, in ‘ Annals of Natural History/ iv, p. 260), gives a Latin description of all the parts except the fruit, and cites Banks and Solander’s manuscript name. He is also the first, so far as I am aware, to explain the process by which the Maoris got rid of the poisonous properties of the seeds, and rendered them edible. A. de Candolle (Prodromus, viii, p. 145), in 1844, refers to the genus under the Theophrastaceae as ‘ forsan praesentis ordinis sed corolla polypetala dicitur et placentatio ignota.’ In T848 Sir William Hooker figured C. laevigata from 3 E 2 746 Hems ley.— On the Genus Cory nocarpus, Forst ., cultivated specimens in the ‘ Botanical Magazine/ t. 4379, where the stamens are represented and described as alternate with the petals ; and the plant is doubtingly referred to the Myrsinaceae. In 1852 Sir Joseph Hooker described it in greater detail (Flora Novae Zelandiae, i, p. 48) and discussed its affinities, with the result that he placed it in the Ana- cardiaceae, ‘ though unable to indicate direct affinity with any plant of that order, except perhaps with Mangiferal He, „ also, describes the stamens as alternating with the petals. This was followed by Bentham and Hooker in 18 62 (Genera Plantarum, i, p. 425), where it is placed in the Anacardiaceae, without any remark on its anomalous structure, except that under ‘Formae Abnormes’ it runs: ‘ Stamina cum squamulis alternantia in Corynocarpo.’ Sir Joseph Hooker, in 1864, (Handbook of the New Zealand Flora, p. 46) still held the same view of its affinities. In 1889 Kirks ‘Forest Flora of New Zealand 5 appeared, and it contains (p. 17 1, t. 88) a figure and description of Corynocarpus laevigata , but the figure is crude and the description faulty, and one can only suppose they were made from imperfect, dried specimens. The enlarged parts of the flower give no idea of structure, and the ripe fruit, unusually small, is represented as erect. In 1897 Engler (Die natiirlichen Pflanzenfamilien, Nach- trage, p. 215) redescribed and figured C. laevigata as the type of a new order (Corynocarpaceae), partly from fresh material cultivated in the Berlin Botanic Garden. His description does not agree in some particulars with what I have observed, but I have no fresh material before me to test certain characters, which may disappear or become very obscure in the dried state. For example, he describes the sepals and petals as 3-5, ciliate, the former deciduous, and the disk as rather broadly annular with five short lobes. Among the numerous flowers I have examined, none was trimerous nor even tetra- merous, and the sepals never free and deciduous. Dr. Engler is the first and only writer, so far as my researches go, who has observed and described two styles to with Descriptions of two New Species . 747 the gynaeceum. He also describes and figures a second cell containing the rudiment of an aborted ovule. But, although I have found a second rudimentary style in all three of the species described here, I have not succeeded in finding a trace of a second cell or cavity in any one of the three. Dr. Engler agrees that Corynocarpus belongs to the Sapin- dales, but the~absence of resin-ducts, in his opinion, excludes it from the Anacardiaceae, and the peculiar structure of the androecium from all the orders of the group ; hence, he says, it must be regarded as the type of an independent order, to be called Corynocarpaceae. He places it in his Subseries Celastrineae, characterized by having no resin-ducts. This Subseries includes the Cyrillaceae, Pentaphylaceae, Corynocarpaceae, Aquifoliaceae, Celastraceae, Hippocrateaceae, Stackhousiaceae and Staphyleaceae. On the whole I am in favour of giving certain isolated, aberrant genera ordinal rank, rather than placing them at the end of other orders, from which they differ as much as most neighbouring orders do from each other. I think the absence of connecting links does not justify the latter course, and the existence of a certain type may be overlooked in a synopsis of orders that does not cover the peculiarities of its structure. Of course it would be inconvenient to unduly increase the number of orders ; but how far it is desirable to go I will not attempt to discuss here. With regard to the genus Corynocarpus , I am not sure that the reasons given for separa- tion from the Anacardiaceae are strong enough. Apart from the absence of resin- ducts, there is nothing of importance, in my opinion, to keep it out of that order. But Engler (Naturl. Pflanzenf., Nachtrage, p. 217) adds : c Zudem ist die Entwicke- lung des Androceums bei Corynocarpus so, wie sie weder bei den Anacardiaceen, noch einer anderen Familie der Sapindales angetroffen wirdf I venture to suggest that Pentaspadon , Hook, f., as figured by the author (Trans. Linn. Soc. xxiii, t. 24) and by Engler himself (DC. Monogr. Phanerog. iv, t. 9, figs. 30-36), presents an analogous an- droecium and disk, and differs in the shape and relative 748 Hemsley. — On the Germs Cory no car pus, Forst . , position of the parts of the flower rather than in any funda- mental character. Both genera are pentamerous up to the gynaeceum, but the position of the fertile stamens and the drumstick-shaped staminodes of Pentaspadon is the reverse of what it is in Corynocarpus , and the continuous disk is io-lobed, instead of consisting of five free bodies. The oblique or unsymmetrical, imperfectly 2-celled gynaeceum of Corynocarpus is analogous to that of Cotinus as figured by Engler (op. cit. t. 12, Figs. 29, 30), where he represents an immature drupe, similar to Figures 23 and 24 in our plate (after Engler), but without any trace of a second cell. The gynaeceum of the genus Trichoscypha , Hook, f., has three styles, but the drupe is one-celled and one-seeded. Sometimes, however, a second cell is partially developed, as shown by Engler (op. cit. t. 11, Figs. 11 and 12), though without any trace of a second ovule. The fibrous endocarp of the fruit of Corynocarpus has a parallel in Mangifera , and the minute radicle of a large embryo is repeated in Bouea , Holigarna and other genera. The general aspect of Corynocarpus is so similar to that of Mangifera , and some species of Buchanania , that one would naturally, without examination, sort specimens into the Anacardiaceae, or perhaps into the Myrsinaceae. Anatomical Characters. Coming to the anatomy of Corynocarpus , it is true that there is a total absence of resin-ducts, and Engler lays great stress on this fact. He states (DC. Monogr. Phanerog. iv, p. 173) ‘Omnium Anacardiacearum rami atque ramuli in sectionibus transversalibus circulum phloemati interiori pro- prium canalium succum resinosum continentium extusque libri semicirculis circumdatorum, insuper stratum scleren- chymaticum hypodermatis exhibent.’ This being so, and I suppose no one could write on the subject with more authority than Engler, it seems almost a pity to admit an exception, yet as there is nothing that correlates with it, and with Descriptions of two New Species . 749 having regard to the divergent anatomical characters in some of the most natural of natural orders, I prefer following Sir Joseph Hooker and others in placing Coryttocarpus in the Anacardiaceae. Baillon (Histoire des Plantes, v, p. 327) retains it in the Terebinthaceae, under which, however, he includes the Burseraceae, Olacaceae (in the widest sense), as well as the Anacardiaceae. I am indebted to Dr. F. E. Fritsch and Miss H. Lasker for the following description and illustrations of the anatomical characters of C. laevigata . Anatomy of the Leaf. (Fig. 27.) The leaf-structure is bifacial. The epidermal cells of both sides of the leaf are polygonal in surface view. Those of the upper side are somewhat larger than those on the lower side and have only a very slight altitude in transverse section (ep). Their outer walls are very strongly thickened, and the cuticle Fig. 27. Small portion of a ttansverse section of leaf, showing upper epidermis {ep), 2-layered hypoderm {hyp), clustered crystals {ccr), and a small part of the mesophyll {m). (x 320). is smooth. The stomata are confined to the lower side, and are provided with a pair of subsidiary cells placed parallel to the pore. Beneath the upper epidermis a 1 to 2-layered hypoderm {hyp) exists, the cells of which are polygonal in surface view and 2-3 times the size of the epidermal cells ; their lateral walls are slightly thickened. The lowermost layer of the spongy tissue frequently forms a kind of hypoderm 75 ° Hems ley . — On the Genus Cory no car pus, Forst., beneath the lower epidermis, which shows up in the shape of loosely arranged polygonal cells in surface view. The palisade tissue consists of two layers of almost isodiametric cells, and is not very well differentiated from the loose spongy tissue, the cells of which appear more or less transversely elongated in a transverse section of the leaf. Altogether the spongy tissue occupies about four times as much of the diameter of the leaf as the palisade tissue. The vascular bundles of the veins are all embedded in the mesophyll (m), and the larger ones are accompanied, both above and below, by rather wide-lumened sclerenchyma. A characteristic feature of the leaf-structure is the abundance of large clustered crystals (ccr) ; these occur especially in the two layers of nypoderm on the upper side of the leaf and also in the hypoderm-like, lowermost cell-layer of the spongy tissue. Very frequently also they occur in specially enlarged cells of the mesophyll, arranged in an interrupted line in about the middle of the leaf. Cork-warts occur in small numbers on the lower epidermis. Anatomy of the Axis. (Fig. 28.) In a transverse section of the stem the primary bundles ( pb ) project more or less considerably into the pith ( p ). The vessels of the wood are not very abundant and not very wide-lumened. The main mass of the wood is made up of prosenchyma, part of which is thick-walled and part thin- walled (x), the two kinds of cells lying in approximately tangential bands. The medullary rays (mr) are rather broad, as much as 6-seriate, and their walls are simply pitted. The pith consists of large, rounded, thin-walled, non-pitted cells, many of which contain large clustered crystals (ccr). The pericycle contains isolated groups of rather wide-lumened bast-fibres ( bf ), placed opposite the primary bundles. The cortex (pr.c) abounds in clustered crystals, and these also occur in the secondary bast (s) opposite the medullary rays. The cork (c) arises in the second cell-layer beneath the epidermis ; the cells are thin-walled, flat or somewhat elongated radially. with Descriptions of two New Species. 75i Fig. 28. Portion of transverse section of stem, showing cork (c), clustered crystals (ccr), primary cortex (pr.c ), bast-fibres of pericycle (bf), secondary bast (s), medullary rays (mr), xylem (x), primary bundles (pb) and pith (/). (x 120.) 75 2 Hems ley. — On the Genus Corynocarpus, Forst., Descriptions. Cory nocarpus, Forst. Character Generis. (Hie emendatus et amplificatus.) Calyx inferior, subcarnosus, alte 5-lobus (sepala 3-5, decidua, ex Engler) ; lobi petaloidei, inaequales, duobus exterioribus minoribus, ovati vel fere orbiculares, concavi, valde imbricati. Petala sub- perigyna, calycis lobis similia, isomera, paullo maiora. Stamina 5, petalis opposita et breviora ; filamenta plana, deorsum leviter dilatata, petalis ima basi adnata ; antherae dorsifixae, biloculares, rima longi- tudinali dehiscentes, pollinis granae minimae, circiter 2 5 /* diametro. Staminodia 5, petaloidea, a medio sursum denticulata vel apice acute 3-9-dentata, petalis alternantia. Nectaria (vel disci glandulae) 5, inter se libera, ovoidea vel ellipsoidea, solida, staminodiis opposita et iis basi leviter adnata. Gynaeceum liberum, sessile, nunc uni- loculare, stylo unico, nunc imperfecte biloculare (nonnunquam perfecte biloculare et biovulatum ?) stylis 2 valde inaequalibus (interdum fere aequalibus, ex Engler) ; ovulum unicum, pendulum, anatropum. Fructus drupaceus, anguste ovoideus, unispermus, endocarpio fibroso. Semen pendulum, loculo conforme ; testa membranacea, tenuis, venoso-reticulata, loculi pariete adhaerens ; perispermium nullum ; embryo loculum implens, cotyledonibus plano- convexis, radicula minima hilo proxima supera, plumula haud evoluta. Arbores mediocres vel parvae, sempervirentes, haud resinosae, omnino glabrae, Australasiae incolae. Folia alterna, simplicia, integerrima, exstipulata. Flores hermaphroditi, parvi, albo-viridi, ino- dori, in paniculas terminales vel subterminales quam folia breviores vel aequantes dispositi, in ramulis solitarii vel saepius ternatim fasciculati, brevissime pedicellati, bracteis bracteolisque minutis. Fructus dru- paceus, pulpo eduli, endocarpio fibroso ; semen exalbuminosum, amarissimum, venenatum. Descriptiones Specierum. Corynoearpus laevigata, Forst. Char. Gen. PI. Ins. Mar. Austr. (1776), p. 32, t. 16, floris partes cum fructu valde imperfecto ; FI. Ins. Austr. Prodr. (1786), p. 19. with Descriptions of two New Species, 753 Arbor fructifera spectabilis, usque ad 15 m. alta, trunco 30-60 centim. diametro, sed saepius dimidio minor, interdum frutex a basi ramosus, undique glabra. Ramuli floriferi crassi, teretes, leves, internodiis brevissimis. Folia breviter crasseque petiolata, crassa, valde coriacea, saturate viridia, glaberrima, supra nitidissima, oblongo-lanceolata, oblanceolata vel interdum elliptica, interdum usque ad 2-5 decim. longa sed plerumque minora, apice saepissime rotundata, basi cuneata vel subcuneata ; costa valida, infra elevata, venis immersis obscuris. Paniculae densae, per anthesin quam folia saltern dimidio breviores, ramulis ac pedicellis brevissimis crassis subcarnosis. Flores circiter 6-7 millim. diametro; bracteae bracteolaeque vix acutae. Sepala fere orbicularia, 2-3 millim. lata, quam petala paullo breviora. Petala obovato-spathulata, margine obscure eroso-denticulata. Stami- nodia oblongo-spathulata, apice rotundata, margine praecipue supra medium obscure eroso-denticulata (‘ apice tricuspidata, cuspide inter- medio duplo maiore/ Banks et Solander, manuscr.), quam petala circiter dimidio breviora. Fructus drupaceus, anguste ovoideus vel ellipsoideus, saepe leviter obliquus, plerumque 2-5-4 centim. longus, sed interdum usque ad 5*7 centim. longus, primum atroviridis, demum aurantiacus, levis, glaber, nitidus. — Bot. Mag. lxxiv (1848), t. 4379, quoad positionis stamina falsa; Gard. Chron. n. s. xx (1883), p. 397, fig. 61, ramus foliifer fructiferque ; Kirk, For. FI. N. Zeal. (1889), p. 1 7 1, t. 88, quoad flores mala; Featon, Art Album of the New Zealand Flora (1889), p. 100, t. 2, flores et fructus; Harris, New Zealand Berries, t. 4, fructifer ; Corinocarpus laevigata , Lam. Encyc. Bot. ii (1786), p. 107, et Tabl. Encyc. ii (1793), p. 128, t. 143 (descr. et fig. ex Forster) ; Merretia lucida , Banks et Solander, descriptio cum icone colorata inedita in Mus. Brit. New Zealand : common in North Island from North Cape to Cook Strait, especially in littoral districts ; rare in South Island, where it is restricted to a few localities in the Nelson, Marlborough and Canter- bury Districts. The highest southern localities are in Banks’s Peninsula. Chatham Islands : common on the main island. Kermadec Islands : plentiful on Sunday Island. Corynocarpus similis, HemsL, species nova, adspectu C. laevigatae ) a qua differt foliis basi obliquis latioribusque, inflorescentia folia aequantibus vel superantibus, et staminodiorum forma. Arbor usque ad 12 m. alta (fide Cominsii) ramulis floriferis crassis. 754 Hems ley. — On the Genus Corynocarpus, Forst Folia distincte petiolata, crasse coriacea, oblongo-lanceolata vel elliptica, usque ad 15-20 centim. longa, maxima 8 centim. lata (4, plus minusve imperfecta, visa) apice subacute acuminata. Panicula (unica tantum visa) per anthesin folia aequans, laxa, ramulis patenti- bus. Flores circiter 10 millim. diametro, distincte pedicellati, pedi- cellis bractea bracteolisque duabus basi suffultis. Sepala fere orbicularia, quam petala paullo breviora. Petala obovato-spathulata, margine obscure irregulariterque denticulata. Staminodia ligulata, petala fere aequantia, apice saepissime acute 5-7-dentata. Fructus edulis (fide Cominsii). Northern New Hebrides : Torres Island, Banks’s Group, Arch- deacon Comins, 343, herb. Kew. The fruits belonging to this and some other specimens were by some means misplaced, and none have been found that could possibly belong to Cory nocar pus. Corynocarpus dissimilis, Hemsl., species nova, a C. laevigata et C. simili foliis minoribus multo tenuioribus graciliter petiolatis et floribus minoribus recedit. Arbor, vel frutex, minus robusta quam species supra citatae. Folia vix coriacea, elliptica vel oblongo-lanceolata, cum petiolo 6-12 centim. longa et 5-6^ centim. lata (specimen unicum visum ramulorum duorum cum foliis paucis et inflorescentiis duabus sistens), apice obtusissima, basi subrotundata, venis inconspicuis. Paniculae quam folia breviores. Flores 4-5 millim. diametro, distincte pedicellati, pedicellis basi bractea et bracteolis duabus minutis suffultis. Sepala elliptico-rotundata. Petala obovato-rotundata, margine irregulariter eroso-denticulata. Staminodia sursum dilatata, apice saepius acute tridentata, dente intermedio longiore. Fructus ignotus. New Caledonia : Valine de la Tihouaca, pres Wugap, Vieillard, 2244, in herb. Kew. Since the foregoing description was written, I have found a reference to a New Caledonian species in Baillon’s Histoire des Plantes, v (1874), p. 327 : * Species forte duae, quarum altera Austro-Caledonica, altera autem C. laevigata , Forst/ In all probability it is the same as that described above, but there is no description and no indication of how it differs from the original species. with Descriptions of two New Species . 755 Economic History. Corynocarpus laevigata occupies, among plants, a promi- nent position in the history and traditions of the Maoris of New Zealand and the Morioris of the Chatham Islands. It is one of the few trees of the country yielding an edible fruit, and it was of great importance to the aboriginal inhabitants as an article of food. One of the most interesting points con- nected with it is the tradition, both in New Zealand and the Chatham Islands, that the immigrant ancestors of the Maoris introduced this tree from the unknown island of Hawaiki. Geographers are not agreed as to the position of this island, and the fact that the genus Corynocarpus was unknown outside of the New Zealand region made it difficult to accept this tradition. But the discovery of a species in New Caledonia, and of another, very closely allied to the New Zealand species, in the still more distant New Hebrides, removes the difficulty. Indeed, it seems quite probable that C. laevigata may yet be found in some of the islands of Western Polynesia, but not in Eastern Polynesia, where most geographers have placed the Hawaiki island of Maori traditions. The eastern islands have been more or less thoroughly explored botanically, and the presence of such a distinct and conspicuous tree would hardly have been overlooked. On the other hand, New Caledonia, the New Hebrides, and the Solomon Islands are still, to a great extent, unexplored. C. laevigata , both in a wild, and formerly cultivated state, thrives only in the warmer parts of the New Zealand region. Kirk (Forest Flora, p. 173) states that it is very rare in the South Island, being restricted to a few localities in the Nelson, Marlborough and Canterbury Districts. So it may be inferred that it is probably a native of a warmer country, generally, than New Zealand. Featon(Art Album of the New Zealand Flora, p. ico) regards all the localities in the South Island as the remains of cultivation. The Morioris of the Chatham Islands represented to 756 Hemsley . — On the Gemis Cory nocar pus , Forst., Mr. H. H. Travers (Trans. New Zealand Institute, iv, p. 64) that their Maori ancestors came originally to New Zealand from Hawaiki, and when they migrated to the Chathams they took with them the kumera ( Ipomoea tuberculata) and the karaka ( Corynocarpus laevigata ), but the former did not thrive owing to the moistness of the climate. Travers found the karaka growing abundantly in the immediate neighbourhood of the various old settlements, but not in the general bush of the island, which gives colour to the statement of its compara- tively recent introduction. This, however, does not quite accord with Mr. L. Cockayne’s more recent experience (Trans. New Zeal. Inst., xxxiv, p. 277), for he states that Corynocarpus laevigata is the predominating tree in the £ Lowland Forest,’ by which he means all below the tableland. The Chatham Islands are about 450 miles east of New Zealand in about the same latitude as Banks’s Peninsula. C. laevigata is also abundant in Sunday Island, one of the Kermadec group, which is situated about midway between New Zealand and the Tonga group ; but I have found no historical records in this connexion. Cockayne goes on to state c that according to Mr. A. Shand the aborigines of Chatham Islands . . . did not cultivate the ground at all. The only vegetable foods they made use of were the rhizome of Pteris esculenta [P. aquilina\ and the fruit of Corynocarpus laevigata .’ Whether this means that they did not even plant the seeds of the latter is un- certain. Some writers, however, regard it as almost certain that Hawaiki was the name of one of the islands of the Navigators’ or Samoan group and that the migration was by way of Rarotonga ; but the botany of this group and the neighbouring Tonga or Friendly Islands is so well known that it is extremely unlikely that the genus Corynocarpus exists in either of these groups. And Mr. T. F. Cheeseman, a well-known New Zealand botanist, has recently botanically explored the island of Rarotonga 1 almost exhaustively, so far as the vascular 1 Transactions of the Linnean Society, 2nd series, Botany, vi, pp. 261-313, tt. 31-35* with Descriptions of two New Species. 757 plants are concerned, without discovering any tree of this affinity. Who first published the Maori tradition of the origin of the karaka in New Zealand, I have not ascertained with certainty, but I believe it was Sir George Grey 1 , and it is repeated by Dr. A. S. Thomson 2 , W. Colenso, Hochstetter, Skey, Kirk, and many other writers. The Karaka as an Edible Fruit. Although Corynocarpus laevigata was cultivated in this country as early as 1824, Allan Cunningham appears to have been the first to publish (Ann. Nat. Hist, iv, 1840, p. 260) its Maori name together with some particulars of the fruit and seed and the preparation of the latter for eating. The flesh of this fruit could be regarded as edible only in the absence of more palatable and luscious kinds. In the first place it is very thin, only a line and a half (J in.) in thickness according to Banks and Solander’s description, and not good-flavoured what there is of it. Featon describes it as having a ‘ sweet, insipid flavour, which is much appreciated by the Maoris but rather distasteful to Europeans.’ He adds that even to this day (1889) the natives collect it in large quantities. But the large seeds were the important part. As already stated, they contain a highly poisonous principle in the fresh state, which is removed by baking or steaming and steeping in salt water. Thus prepared they constituted one of the principal and most valued articles of food. They were collected, prepared, and stored in a methodical manner. The intensely bitter, poisonous principle is described by Mr. W. Skey (Transactions of the New Zealand Institute, iv, 1872, p. 316), who names it karakine. Chemical treatment of the extract proved that the principle does not contain nitrogen and is not of an alkaloidal nature, and that it is closely allied to digitaline. ‘ Its deportment with sulphate of copper and potash is strikingly similar to that of digitaline 1 Poems, Traditions and Chaunts of the Maories, 1853. 2 The Story of New Zealand, 1859. 758 Hems ley. — On the Genus Corynocarpus , Forst ., to the same tests. Both give green precipitates of a tint very similar to arsenite of copper. . . . Taking all these facts into consideration I am inclined to believe that the bitter of the karaka nut is a glucoside, and that digitaline falls into the same class, though I have not known this character imputed to it before.’ Skey failed to find any alkaloid body in the nut (seed), and came to the conclusion that the bitter substance is the poisonous part, but he did not establish this by experiment. He also found that the inner bark of the tree is bitter, probably from the presence of karakine, whilst the outer bark is not bitter but astringent, from the presence of tannin. The leaves, the wood, and the sap are sweet. Kirk (Forest Flora, p. 171) states that the leaves are greedily eaten by horses and cattle, and its value as fodder has led to its almost total extirpation in districts. where it was formerly plentiful. In all the recent works cited or quoted, karaka is the only Maori name given ; but Bennett (Gatherings of a Naturalist, i860, p. 346) mentions kopi as an alternative name. Pos- sibly this may be the name of a certain part. Bennett also states that the colonists called it the ‘ cow-tree,’ on account of the fondness of cattle for the foliage. The Forsters record no vernacular name, and Banks and Solander write it chalacha. This spelling may be attributable to Solander alone, as an Englishman would almost certainly have employed k’s instead of ch’s for the hard sound. In conclusion I have the pleasure of thanking Miss M. Smith for the great care she has taken in drawing the dissections ; Sir William Thiselton-Dyer and the Bentham Trustees for defraying the cost of the drawings ; Dr. F. E. Fritsch for the anatomical details ; Mr. G. Massee for drawing the pollen ; and Dr. O. Stapf for kind assistance throughout I also have to thank Mr. Wyndham Fitzherbert, of Kings- wear, S. Devon, for his wide-seeking, though unsuccessful attempts to procure fresh flowers of C. laevigata in the West of England. with Descriptions of two New Species. 759 EXPLANATION OF THE FIGURES IN PLATE XXXVI. Illustrating Mr. Hemsley’s paper on the genus Cory nocarpus, Forst. C. laevigata, Forst . Fig. i. A flower and portion of a branch of an inflorescence. Enlarged. Fig. 2. A flower. Natural size. Fig. 3. Floral diagram, showing pentamery up to gynaeceum. The stamens are opposite the petals, and the glands or nectaries, and the petaloid staminodes are opposite the sepals. Fig. 4. A flower laid open, showing a portion of a sepal on the left, the petals, the staminodes, the stamens and the nectaries. Enlarged. Fig. 5. A petal and its superposed stamen. Enlarged. Fig. 6. A staminode and its superposed nectary. Enlarged. Fig. 7. A sepal and its superposed staminode, copied from a drawing in the Banksian Collection at the British Museum. Enlarged. Fig. 8. A stamen, front view. Enlarged. Fig. 9. A stamen, back view. Enlarged. Fig. 10. Pollen, magn. 400. Fig. 11. A gynaeceum. Enlarged. Fig. 12. A gynaeceum, showing indications of a second carpel or style. En- larged. Fig. 13. Longitudinal section of ovary, showing the solitary pendulous ovule. Enlarged. {Figs. 1-6 and 8-13 are from LyalVs specimens collected in Massacre Bay, Collingwood, South Island, New Zealand!) Fig. 14. Section of a flower, showing two nearly equal styles. Enlarged. After Engler. Fig. 15. A ripe fruit. Natural size. Fig. 16. A fruit from which the flesh has been removed, showing the fibrous endocarp. Natural size. (Figs. 15-16 are from fruits collected by G. Oliver .) Fig. 17. A seed from a smaller fruit with reticulated testa corresponding to the fibrous cords of the endocarp. Natural size. Fig. 18. Embryo from which the testa has been removed, showing the slightly unequal cotyledons with a cap-like growth on the radicular end, which is apparently a second undeveloped embryo. Natural size. Fig. 19. Another view of the same. Fig. 20. Rudimentary second embryo. Enlarged. Fig. 21. Cross section of rudimentary embryo, showing the vascular bundles which radiate from a single basal cord. Much enlarged. Fig. 22. Inner face of a cotyledon and minute plumule and radicle. Enlarged. (Figs. 17-22 are from specimens cultivated, at Tresco Abbey, Scilly Isles, in 1883.) Fig. 23. An immature fruit. Natural size. After Engler. Fig. 24. A longitudinal section showing remains of a second cell and aborted ovule. Natural size. After Engler. 3 F j6o Hemsley . — On the Genus Corynocarpus , Forst . O. similis, Hemsl. Fig. 25. Flowers and portion of a branch of an inflorescence. Enlarged. Fig. 26. A flower. Natural size. Fig. 27. A flower laid open showing petals, staminodes, stamens, nectaries and gynaeceum with two unequal styles. Enlarged. Fig. 28. A petal and a stamen. Enlarged. Fig. 29. A staminode and a nectary. Enlarged. Fig. 30. A 5-toothed staminode. Enlarged. Fig. 31. A gynaeceum. Enlarged. Fig. 32. A longitudinal section of the same, showing the solitary pendulous ovule. Enlarged. {Figs. 25-32 are from a specimen collected by Archdeacon R. B. Comins in Torres Island ’ Northern New Hebrides .) C. dissimilis, Hemsl. Fig. 33. A flower and portion of a branch of an inflorescence. Enlarged. Fig. 34. A flower. Natural size. Fig. 35. A portion of a flower laid open, showing part of a sepal and three petals, staminodes, stamens and nectaries. Enlarged. Fig. 36. A petal and a stamen. Enlarged. Fig. 37. A staminode and a nectary. Enlarged. Fig. 38. A gynaeceum with one style. Enlarged. Fig. 39- A gynaeceum with two unequal styles. Enlarged. Fig. 40. A longitudinal section of ovary showing single cell and ovule. En- larged. {Figs. 33-40 are from a specimen collected by Vieillard in New Caledonia , n. 2244.) o Annals of Botoony M. Smith, del* CORYNOCARPUS L/EV1GATA, Forsb. VoUVII, PI XXXVI. C. SIMILIS, Hemsl. University Press Oxford. C. DISSIMILIS, Hemsl. M. Smith, del! I CORYNOCARPUS L/EVIGATA, Forst. mm, pi. xxxvi. University Press Oxford. C. SI Ml LIS, Hemsl. C. DISSIMILIS, Hemsl. On the Movements of the Flowers of Spar- mannia africana, and their Demonstration by means of the Kinematograph. BY RINA SCOTT. With Plates XXXVII, XXXVIII, and XXXIX. O PARMANNIA africana is a common greenhouse plant, ^ which was introduced from the Cape into Europe as early as 1790. It was named after Dr. Sparmann, a Swedish botanist, who accompanied Captain Cook on his second voyage round the world. It belongs to the order Tiliaceae ; there are three species : 5 . abyssinica , S', palmata ,' and the subject of the present paper. It is well known to the botanist on account of the curious movements of its stamens, which, when touched, gradually move away from the style, leaving the stigma exposed and ready for fertilization by bees. A paper was written on the subject as early as 1841 by Charles Morren 1 . S. africana is found wild in many parts of S. Africa, occurring about the Knysna district and from thence East, but always at no great distance from the coast. It attains a height of about 15 feet, ripening its seeds towards the end 1 Mem. de l’Acad. Roy. de Bruxelles. Ch. Morren, 1841, vol. xiv. [Annals of Botany, Vol. XVII. No. LXVIII. September, 1903.] 3 f a 762 Scott. — On the Flowers of Sparmannia africana, of October or beginning of November and again in March. It is found at the edges of forests outside the tree belt. All my investigations were made on plants growing in a greenhouse. In its natural state the day temperature during flowering rises to a maximum of 92° F. (33° C.) ; but it is seldom more than 80-87° F. (27-30-5° C.), and the nights average about 60-65° F. (i 5 \ 5 _I 8*5° C.), seldom falling lower than 57°F- (i 4 °C.) \ The whole plant is covered with hairs, which protect it during the cold nights on its native mountains round the Cape. The young buds are themselves covered with dense hairs, and are sheltered at an early age by the hairy leaves above them (Fig. 13). Sparmannia africana is an exceptionally favourable plant on which to study reaction to stimulus, as so many of its parts are sensitive. The most strikingly sensitive organs are the stamens : these are arranged in four groups, having an outer circle of staminodes. Both stamens and staminodes are provided with curious tooth-like outgrowths, few in number on the stamens, but becoming more and more numerous and conspicuous as the outer staminodes are reached. All of these are sensitive to touch ; if only one stamen be touched, the stimulus spreads until all the stamens and staminodes have moved outwards away from the stigma. These movements have been described in great detail by various writers 2 . Then the petals and sepals respond to the stimulus of light, and lastly the flower as a whole is capable of special move- ments, regulated not merely by the curvature of the pedicel, but by the action of the pulvinus or joint situated at a short distance below the flower. The following observations, which extend over two seasons, are principally on the movements of the flower bud and flowers up to the time of the setting of the fruit. Three complete inflorescences from bud to fruit were drawn 1 I am indebted to Mr. Harry Bolus, of Cape Town, for these details. 2 Haberlandt, Sinnesorgane im Pflanzenreich, pp. 46-51. Leipzig, 1901. . 1 and the Use of the Kinematograph . 763 every day and night, and from these data the following results were obtained : The inflorescence is an umbel. At first the buds hang all on one side of the main peduncle, both buds and pedicels are densely hairy. The pedicel of each bud is jointed. This curious joint or pulvinus is situated at an average distance of about 1 cm. from the bud, and will be found to be much swollen on the side away from the bud. The swelling becomes more noticeable as the bud grows older and the functions of the joint come into play. This joint, which is present in all three species of Spar- mannia , bears in its action and structure some resemblance to the pulvinus found on such leaves as those of the sensitive plant ( Mimosa pudica ), and helps to regulate the position of the bud, flower or fruit at different times of its development. It is capable of causing the most delicate movements of the bud or flower, and responds readily to the stimulus of light. The greenhouse plant is specially favourable for the study of the joint. Owing to the fact that Sparmannia africana is used as a winter flowerer here, the flowers open much less readily than they do in their natural state. This can be easily seen, if a dried wild specimen be compared with one from a greenhouse. In the specimens in the Kew Herbarium one frequently finds flowers and ripe fruits of which some have already fallen on the same umbel, and very often (see PL XXXVII, Fig. 14) an umbel has nine or ten open flowers at a time, while in the greenhouse specimen quite frequently days pass without a fresh flower opening, while in one umbel drawn, the last flower lost its petals on March 19 and the first fruit was not ripe till April 25. So that a joint, which under natural conditions might only be used for a few weeks, will in a greenhouse specimen have to remain active for as many months. Thus the joint develops by use, and, after a cold month, when the temperatures have been too low to admit of the flowers opening, becomes quite a conspicuous feature of the plant. 764 Scott. — On the Flowers of Sparmannia cifricana , The peduncle circumnutates and grows during flowering on an average if inches (4^ cms.) in height, and the flower-bud rises 3 inches ( 7 1 cms.) in height. These results were arrived at by means of a diagram made by careful daily measurements on a cylindrical glass enclosing the inflorescence. Figs. 1-12 represent stages in the development of an inflorescence, and are drawings selected from a continuous series beginning on March 6 and ending July 23, 1902, drawn every day and every night during flowering. If Fig. 1 is first examined, three buds will be seen moving up into the flowering position ; we will first follow the be- haviour of bud 3, in Figs. 1, 2, and 3, as this has only just started from the pendent position parallel to the main peduncle. The first drawing of bud 3 was made at 11 a.m. March 6, temp. 63° F. (17-5° C.) on a fine sunny day, and the movement of the pedicel was very rapid ; the amount of movement attained by 4 p. m. is shown by the dotted lines in Fig. 1. Here it will be seen that the whole pedicel is straightening itself ; it continues to rise in this way all through the night (Fig. 15 represents the position of a similar bud at 4.30 a.m.), until on March 7, 10 a.m. it had attained the position shown in Fig. 2. The pedicel then makes a sharp bend as seen in 3 ( or better in Fig. 31) the bud is dropped into the vertical position ready for flowering by the movement at the joint (see Fig. 5 where 3 is in flower), and in Figs. 1 (bud 1), 52 , 55, 58. The exactness of the vertical position attained is very remarkable ; no doubt the opening bud has its stamens protected from injury till the last minute before opening by this means, and, if rain falls, the hairy sepals are in the posi- tion of an umbrella, ready to throw it off, without injury to the more internal parts of the flower. We must now follow the opening of the bud. (Figs. 22-25, 30-39, 58-64 show this process.) The bud on a hot day begins to open as a rule a short time before sunrise. For instance, on the morning when the sun rose at 6.32 a.m. March 8, at 5.45 a.m. I found the buds and the Use of the Kinematograph. 765 breaking open on all sides temp. 50° F. (io° C.), till at sunrise they had attained the position shown in Figs. 35 and 59. Up till now the stamens have not been exposed ; now for the first time a few of the staminodes raise themselves and begin to show between the petals (see Figs. 23, 24, 56 and diagram), and the rapidity with which the flower opens from this stage depends on the temperature. If it is sunny and has reached about 6o°F. (15*5° C.) by then the process of unfolding is so rapid that it is difficult to draw the different stages (an example of this rapid opening is shown in Figs. 22-25) where the time interval between 23 and 24 is only ten minutes ; but if, on the other hand, the temperature remains low, these little hooked staminodes, which are now raised into the position in which they will be in an open flower, appear to be peculiarly sensitive, and from observations made later seem to transmit a message to the other parts of the flower, causing it to finish opening as soon as the temperature is right. They are a most conspicuous feature in a flower during the critical moments of its opening and closing, but even when a flower is opening rapidly, if carefully watched, one can see that these staminodes are raised first. The flower continues to open gradually, the petals becoming less and less crumpled, the sepals and petals rising one by one (see Fig. 24) until eventually on a sunny day the sepals are pressed tightly back and the petals raised to the utmost, exposing the stamens (Figs. 5 (2 and 3), 25, 39, 64). The style is at first shorter than the stamens, but by the following day has grown to their length. If very cold weather prevails, and the flower is prevented from opening for some days, then the style is found to be its full length as soon as the flower opens. The opening is generally complete by about 9 a.m. The flower remains wide open during sunlight ; as the sun’s power diminishes, the flower-stalk moves from the joint until the flower again reaches the vertical position (Fig. 4), the petals close over the stamens one by one (see Fig. 1 5, one flower has one petal closed, the other two and Figs. 16-20), then the 766 Scott. — On the Flowers of Sparmannia ofricana , sepals close too, and the flower shuts for the night (see Fig. 4 (2), where the flower 2 in Fig. 3 is seen closed and the older flower 1 has just been dropped into the vertical position preparatory to closing. Also Fig. 6, where flower 3 in Fig. 5 is closed). The first day then the flower is small, has a short style, and generally closes about 6 p.m. (see Figs. 25, 53, and 63). On the second day the flower begins opening much earlier than on the first occasion — 5 a.m. (when sunrise is 6.32 a.m.), and opens so rapidly that it is difficult to follow its move- ments. The style has grown as long as the stamens, which are now very sensitive, and at the slightest touch move rapidly away from the stigma. The flower is closed by 9 p.m. (see Figs. 54 and 64). The third day the flower again opens as before, the stamens are still sensitive, but the flower is very late going to sleep. At 10.30 p.m. the petals had fallen into the flat open position (Fig. 4, 1), at it. 30 one petal was closed, and it was not until 4.30 a.m. that the flower was completely shut. The fourth day the flower is flat open, and again goes to sleep late. The fifth day the flower does not open so widely, and the stamens are no longer sensitive. At the time when the other flowers are shutting for the night, it shuts slightly but never reopens. Gradually it closes more and more, and during this time it is gradually attaining the vertical position (see Fig. 5, Flower 1, which in Fig. 6 has shut and will not reopen.) In Fig. 7 it has almost attained the vertical position. As the flower withers, if bees have not been plentiful the pollen is mechanically extruded from the stamens. This is the usual course of a flower’s life, when fertilization has not taken place. It varies to a certain extent according to weather conditions. For instance, sometimes a flower does not reopen in the position of the second day, but at once takes up the flat open position of the third day. The progress of the flowers from day to day is very difficult to watch accurately. The flower of to-day takes up the position occupied by yesterday’s flower. This was well brought out and the Use of the Kinematograph . 767 by plotting the flowers as explained on p. 764, where it was found that the flowers in succession occupied one another’s places, so that unless each flower be accurately drawn daily it would be very easy to confuse the identity of the individuals. I will now describe the progress of a fertilized flower, Fig. 8, Flower 9. This opened first at 2 p.m. on March 12. Closed 6 p.m. Second day. Bees were introduced into the greenhouse, and the flower was fertilized (Fig. 21). Stigma as long as the stamens. Began going to sleep 8.45, March 13. The flower continued to open and close on the 14th, 15th, not beginning to close on the 15th until 10 p.m. After this it gradually closed its petals, whilst moving up into the vertical position. On March 18, six days after it first opened, the whole pedicel moved down from the vertical into the horizontal position (Fig. 9, Flower 9) ; the flower was turned up vertically by movement at the joint. The ferti- lized flowers always behave in this way, thus getting out of the way of the buds and open flowers. On March 19 the flower still opened a little, the pollen was ripe and plentiful, and the pedicel was gradually moving up again. The petals now fell off, the stamens withered and the fruit swelled. It was ripe in June (Fig. 11). A layer of periderm is formed at the joint, and it is here that the fruit detaches itself when ripe (Fig. 14, a figure drawn from a herbarium specimen). The seed was sown on June 22, and the seedling came up and was figured on July 23 (Fig. 12). The ovules are capable of being fertilized in cold weather also. I have one example of a fertilized ovule (Jan. 8) with endosperm, but the fruit cannot ripen under these conditions. Temperature about 40° F. (4-5° C.). If we now review the general movements of the umbel, we shall see that the arrangement is such as to ensure an even distribution of the flowers and afterwards of the fruits over the sphere of the umbel, so that each flower or fruit is 768 Scott.- — On the Flowers of Sparmannia africana, separated from its fellows and is exposed to the best advantage to the sun’s rays. The buds when young hang down close to the peduncle out of the way. As the flowers open they rise, and again move out of the way into a close vertical cluster after fertilization. Then the fertilized flowers move down one by one into the horizontal position, and gradually rearrange themselves equally over the sphere during ripening ; the last fruit remaining in the vertical position. The whole development from bud to seedling thus occupied four months ; this is no doubt a very much slower process than it would be under natural conditions. As the flowers only open well during sunlight with a temperature of about 6o° F. (i 5*5° C.) and the plant is flowered in our early spring, one often gets only one flower at a time on an inflorescence, and many days may elapse before another has the opportunity of opening, while on a hot day one may get three or four fresh flowers opening at the same time. The plant flowers again six months later, in September, though it is seldom given the opportunity here, as the usual treatment is to cut it back after the early flowering. The opening of a normal bud has now been described, but the weather conditions make very considerable alterations in the habits of the bud. The opening is retarded by fog, probably principally because fog tends to keep down the temperature, which must be about 6o° F. (15*5° C.) for a flower to open. The bud will not go on opening if for any reason the temperature falls. One bud (Figs. 42 and 43) began opening at 10.50 a.m. temp. 7 2 0 F. (22-5° C.) on a bright sunny day. At 11 a.m. it put up two sepals (Figs. 44 and 46) ; at 12.10, temp. 66° F. (19 0 C.), it was putting up a third (Figs. 47 and 48) when a hailstorm reduced the temperature below 6o° F. (15*5° C .) 1 . This is the stage at which in the normal opening the stamens 1 The hailstorm no doubt reduced the temperature much more than would have been the case in the open, as the glass of the greenhouse was made wet and cold by the falling hailstones, and the evaporation afterwards tended still further to make the temperature fall. and the Use of the Kinema tograph. 769 begin to expand, but here only a few staminodes were protruded and erected from between the petals (Fig. 50). This happens so constantly when a flower is checked in opening (see Fig. 56) that it seems as if in some way the delicate projections from the filament must be more sensitive to temperature changes than the rest of the flower, and are perhaps able to send a message to the other parts. At 12.40 p.m. the temperature again rose above 6o° F. (15*5° C.), and it put up a third sepal (Figs. 49 and 50) at 2.20 p.m. Another hailstorm so reduced the temperature that the flower closed for the night (Figs. 51 and 52). Figs. 53 and 54 show it open the next and following mornings. In Fig. 53 the style will be seen to be short, while in Fig. 54 (drawn the following day) it had grown to the length of the stamens. Another flower (Fig. 55), which began opening at 10 a.m., kept one sepal up (Figs. 55—57) till 12.30 p.m., and then a hailstorm lowered the temperature, and it closed for the night (Fig. 58). I watched one flower on Nov. 20, which had been trying to open for three days ; this had developed the most conspicuous joint, which I ever observed. On warm sunny days the buds go on. developing, and one sometimes has the good fortune to be able to watch the whole process of opening without getting up before sunrise. Figs. 22-25 show a flower, which began opening at 12 p.m. and was full open at 2.5 p.m., closed at 6 p.m. Note in Figs. 23 and 24 the staminodes rising above the first opened petal. The so-called ‘ sleep * of these flowers is a very interesting and variable process, and probably has some connexion with their fertilization, as the flowers no longer close well after the stamens have ceased to be sensitive. The plant is very active at night. The buds move upwards and outwards in the most vigorous way all night, and the style also grows in length during the night, so that a one-day-old flower, which had a short style on closing about 6 p.m., has on opening the following morning a full-grown style as long as the stamens. 770 Scott.— On the Flowers of Sparmannia africana , Effect of Rain on the Flower. Kerner describes the effect of rain on the flowers of Sparmannia africana b He says : ‘ The flowers are inverted and their anthers are turned towards the ground and covered over by the petals. When the flower is open, however, the petals are slightly tilted back, i. e. upwards. The margins of the petals overlap one another, and their outer surfaces, which in consequence of the inverted position of the flower are uppermost, thus form a basin open to the sky. When it rains this basin placed above the anthers fills with water, thus adding to the weight borne by the stalk, and as drop after drop increases the strain upon the latter, a point is at length reached when the basin tips over, letting the water flow over its edge, without wetting the stamens suspended beneath it.’ I have repeated this experiment ; Fig. 26 shows the position of the flower before the rain-shower, Figs. 27 and 28 after the rain has begun. For a long time the cup fills and empties, shooting out the water in the direction of the arrow in Fig. 28 in a most perfect manner, and the stamens remain perfectly dry. The long, dense hairs of the sepals which form the cup also help to throw off the water rapidly. But if the rain is long continued or very heavy, the stamens eventually get wetted, as seen in Figs. 27 and 28, where the drops can be seen running off the stamens, which are hanging together in groups. Fig. 29 represents the same flower shutting up at 7 p.m. I found that if the stamens were once wetted the flower did not reopen, though if they kept dry they opened as usual the following day. Chloroform Experiments. One flower was chloroformed for a few seconds ; the stamens were no longer sensitive, but recovered their sensitiveness again after a short lapse of time. 1 Kerner von Marilaun, A., Eng. Ed. 1895, vol. ii, p. 119. and the Use of the Kinematograph. 771 A young inflorescence with all flowers in bud was chloro- formed next, and the results watched. No apparent change took place, but the development of the inflorescence was very curiously affected. The drooping buds went straight up into the vertical position, the position which the flower assumes after fertiliza- tion. The open flowers behaved in various ways : One took up the vertical position, whilst others moved down into the horizontal position, as in Fig. 9, 9. Some of the buds did not open at the usual time, but the style grew in length, as would have been the case normally the day after the opening of the flower. These buds presented the most abnormal appear- ance, with the stigma hanging out, though the sepals were quite closed. One bud measured 1 cm., and the style pro- jected 6 mms. from it. In some cases, after a few days, the flowers fell off at the joint. The effect of the chloroform seems to have been to make the buds and flowers lose all count of time. A bud, after recovering from chloroform, often missed out several stages of its development, another would grow a long style as if it were a two-day-old flower, while an open flower would take up the position of a fruit, or fall off at the joint, as if it were a ripe fruit. The difficulty in carrying out these experiments is that it is so very easy to give too much chloroform and poison the inflorescence so that it never thoroughly recovers ; in these cases other inflorescences are generally affected too. Kinematograph Experiments. It struck me that the inflorescence of 5 . africana would be admirably adapted for an experiment with the kinemato- graph. The inflorescence could be photographed at intervals while young, so as not only to show the opening and the closing of the flowers and the movements of the stamens, but also the development of the inflorescence from bud to fruit. The 772 Scott. — On the Flowers of Spar mannia africana , series of photographs taken could then be projected with the lantern on the screen, and the development of the inflor- escence, which in reality takes several months, could be watched in progress and could pass before the spectators on the screen in a few minutes, until the buds first shown had become fruits. The difficulty of trying this experiment was principally one of expense. Professor Pfeffer 1 , of Leipzig, has made many successful botanical demonstrations with a kinematograph and has de- vised a very perfect apparatus for class demonstration, but the expense of his apparatus (exclusive of the cost of his original experiments) is too great to make it possible for use by the private investigator ; one of the most serious items being the cost of production of each film, which amounts, Prof. Pfeffer tells me, to ninety marks (£4 ioj.), while the apparatus for taking the photographs cost £45 (exclusive of the kinematograph and lantern for demonstration). I at first experimented with a small film kinematograph, but the results were not satisfactory, as the machine was not suitable for making time exposures, and the makers were unwilling to help adapt their machine for scientific work. Also the life of the films when obtained was so short. The following experiments were made with a machine called the Kammatograph, in which the photographs are taken on a glass disc instead of on a film. In the use of this machine I have received every possible help from the inventor 2 of it, who has done his best to adapt it in every way for the work. A short description of the machine will first be necessary to those who have not seen it. A glass disc of 12 inches in diameter is suspended in a metal ring ; this disc is coated with a sensitive emulsion, and is in fact a large circular dry plate ready for use in photography, capable of taking 350 photographs. (Half one of these plates, after the photographs have been taken on it, is shown in Fig. 65, PI. XXXIX.) 1 Jahrbuch f. wiss. Bot., 1900, vol. xxxv, p. 38. 2 Messrs. Kamm & Co., 27 Powell Street, E.C. 773 and the Use of the Kinematograph, This glass disc, when ready for use, is put into a light-prool box, and by means of a handle at the side can be spirally rotated, so that every part of it is in turn exposed before the small oblong opening in front of the lens. In ordinary kinematograph work the handle is rotated at a uniform speed, and a series of snapshots are produced, but for the work now required it is necessary to take time exposures, as the light in a greenhouse would seldom, if ever, be good enough for instantaneous photography, and also, if it were possible, the number of photographs thus obtained would be unnecessarily large ; as a large number are only required when rapid move- ment, such as that made by the stamens when touched or when a bud is opening, is taking place. For many parts of the day a photograph taken every quarter of an hour is sufficient. The practical difficulties were very great ; the principal ones were : (1) To obtain absolute rigidity of the apparatus. (2) Uniform exposure for each photograph, as photographs had to be taken at all times of the day and night and in all weathers. (3) The difficulty of having some one always watching the plant. (4) Compensating accurately for the growth in length of the inflorescence, so that the part of interest is always in the field. The first difficulty was removed by the construction of a heavy metal tripod stand. The second was soon removed by the use of an accurate actinometer, which must, however, be used for almost every photograph to ensure perfect results. The night photographs can be taken by means of a magnesium wire, accurately measured in lengths, or better still, by those who have electric light installed, with an arc light. For the third difficulty I am afraid there is no solution but the adoption of an elaborate and costly automatic mechanism. This has been done by Professor Pfeffer. 774 Scott. — On the Flowers of Spar mannia africana , It certainly would be a great advantage to be able to take photographs mechanically through the night, as unfortunately this plant, so far from following the human habit of sleeping through the night, seems to be peculiarly active between the hours of i and 5 a.m. For the overcoming of the fourth difficulty I am indebted to Mr. Kamm, who constructed a very accurate sight to the machine, by the use of which the elevation could be readjusted every morning. I will give a brief account of the kinematograph picture illustrated, Fig. 65. It was begun at 8.30 a.m. March 6, 1903. As many photographs as possible were taken of the bud while opening ; then it remained more or less stationary for some time, and photographs were only taken at half-hour intervals until the flower began to go to sleep, when regular photographs were again taken with longer and longer time exposures as the light decreased, and then by means of magnesium wire. The following morning photographs were taken by magnesium wire from 4.30 a.m. until sunrise (see Fig. 66), when time exposures were again taken. To show the movements of the stamens when touched, instantaneous photographs were taken by turning the handle of the machine as in ordinary kinematograph work. After two days’ work another difficulty arises — the" flower- stalk elongates, so that if a new adjustment is not made one finds the future photographs show only the stalk. This is remedied by raising the stand of the Kammatograph with the help of a very accurate sight adjustable for any distance above 9 inches, and then starting again. Of course one loses the growth of the flower-stalk, but this is inevitable, unless a much larger photograph is taken, " which would involve a much more costly machine. The sensitized plate is then removed and developed just like an ordinary plate, and when dry the positive is printed from it in a few minutes. I must here state the one drawback to the use of this machine : there is no means of remedying a mistake. 775 and the Use of the Kinematograph. With the film kinematograph over- or under-exposure, or a photograph which has been spoilt by accidental movement, has only to be missed out when printing, or if necessary the next photograph can be printed twice. On the other hand this machine has great advantages. The developing of the whole series of 350 photographs only takes the same time as that required for developing any ordinary sensitive plate, and printing is also perfectly simple, as the negative is simply placed on a positive plate exposed for a definite number of seconds to the light of a lamp and then fixed. Any number of positives can thus be made by an ordinary photographer with a very small expenditure of time. The cost of producing each negative is 3s. 6d. and each positive costs the same amount, so that each subject taken costs js. My experiments with both kinematographs extend over more than a year, and I have only quite recently succeeded in producing fairly good results ; but I think that most of the principal practical difficulties are now surmounted, and that the machine is in a fit condition for experimental work. I have used it successfully for other subjects, such as climb- ing plants, to show the movements of the leaves of the sensitive plant. I believe these are the first kinematograph experiments under natural conditions, daylight being used and artificial light only resorted to at night. It was thus possible to leave the plant undisturbed throughout the time of observation. I am indebted to Miss M. Smith, of Kew, for kindly drawing two figures for me from photographs. I am making microscopical investigations of the parts of the plant connected with movement, which promise some interesting results, but have thought it better to defer this to another paper, which I hope to publish shortly in conjunc- tion with Miss Richards of the Royal Holloway College. 3 G jy6 Scott.- — On the Flowers of Spar mannia africana , DESCRIPTION OF FIGURES IN PLATES XXXVII XXXVIII, AND XXXIX. Illustrating Mrs. Scott’s paper on Sparmannia africana. Fig. i. March 6, 6o°, n a.m., sun out, dotted lines, 6o°, 4 p-m., sun out. Fig. 2. ,, 7, 57 0 , sun out, 10 a.m. Fi g- 3- ,> 8, 57 0 , sun out, 9.30 a.m. Fig. 4- ,, 8, 35 0 , 8.50 p.m. Fig- 5. ,, 9, Jo°, sun out, 10 a.m. Fig. 6. „ 9, 62°, 9.15 p.m. Fig. 7. „ 10, 56°, dull, 10 a.m., flower 3 shut, 10 p.m. Fig. 8. ,, 15, 68°, sun out, n a.m. Fig- 9- „ 18, 58°, „ 2 p.m. Fig. 10. April 25, 68°, „ 3 p.m. Fig. 11. June 22, 7.30 p.m. Fig. 12. July 23, 1902, seedling sown June 24, 1902. G-G level of ground. Fig. 13. Shows buds covered by leaf, from photograph. Fig. 14. Drawing of ripe fruit from Kew Herbarium of wild Sparmannia. Fig. 15. Drawing from kinematograph photograph, showing bud rising at night while flowers are closing. Fig. 16. Sleep position, 7.30 p-m., 56°, 2 petals shut. Fig. 17. „ „ 8.30 p.m., 55 0 , 1 petal shut. Fig. 18. „ „ 9.10 p.m., 54 0 . Fig. 19- „ „ 7.30 p.m., 56°. Fig. 20. „ „ 9.10 p.m., 54°. Fig. 21. Bees fertilizing flowers, 11 a.m., 65°, March 13, 11.40 a.m., 65°, flower bud began opening. Fig. 22. 12 p.m., 70°, March 25. Fig. 23. 12.50 p.m., 69°. Fig. 24. 1 p.m., 70°. Fig. 25. 2.5 p.m., 72 0 , asleep 6 p.m. Fig. 26. Position of flower 12 p.m., 55 0 , before rain. Fig. 27. „ „ after rain, March 4, 1902. Fig. 28. „ ,, „ „ Fig. 29. Same flower at 7 p.m., 52 0 , „ Fig. 30. 1 b, 10 a.m., March 22, 6o°, sun out. 1 C 5 >> }> 22 > 11 » Fig. 31. 2 b, 1 p.m. ,, 22, 63° „ 2 c > n 22 > >> » There was a hailstorm at this time, and the flowers did not open further. Fig. 32. 3 b, 6.45 a.m., March 23, 48°, sun out. 3 c 5 n n 2 3 > >> » Fig. 33- 4 b > 7-2° a.m., „ 23,50°, „ 777 and the Use of the Kinematograph. Fig. 41. 4 c, 7.20 a.m., March 23, 50°, sun out. Fig. 34- 5 b, 9 a.m., 5 C 9 99 Fig. 35- 6 b, 9.5 a.m., Fig. 36. 7 b, 9.10 a.m., Fig. 37. 8 b, 9.20 a.m., Fig. 38. 9 b, 9.30 a.m., Fig. 39. 10 b, 9.45 a.m., Fig. 40. 11b, 11.50 a.m., 6 c, „ Fig. 42. 1, 10.50 a.m., Fig. 43. Other view, Fig. 44. 2, 11 a.m., Fig. 45- 3» IT -20 a.m., Fig. 46. Other view. Fig. 47. 4, 12.10 p.m., Fig. 48. 5, 12.40 p.m., Fig. 49. 6, 2.20 p.m., Fig. 50. Other view, Fig. 51. 7 » 8.30 p.m., 52 0 . Fig. 52. ,9 „ Fig. 53- 8, 10 a.m., March 22, 6o°. 23, 55 9 „ 2 3 > >9 99 23, 9, 2 3 > 99 99 2 3 > 99 99 2 3 , „ 23, 6o°, „ 259 55°9 2 59 99 99 21, 72° 2I > 99 99 2I 9 99 99 21, 68 °, ,, 21,66°, „ 21,66°, „ other view. 21, 6o° (violent hailstorm). 21 M 1 a 9 99 99 Fig. 54. 9, i p.m., ,, Fig. 55- 2 a, 11.30 a.m., Fig. 56. 3 a, 12.30 p.m.. Fig. 57 - 3 a, Fig. 58. 4 a, 8.30 p.m., Fig. 59- 5 a 9 6.40 a.m.. Fig. 60. 6 a, 6.45 a.m., Fig. 61. 7 a, 7 a.m., Fig. 62. 8 a, 7.10 a.m., Fig. 63. 9 a, 7.35 a.m., Fig. 64. 10 a, 9 a.m., 22, „ 22, 63°. March 22, 68°. „ 22,63°. „ „ ,, other view of 56. „ 22,58°? „ 23, 48°. 9 23, „ 9 23, „ 9 23, 50° 1, 23, 51° ) 9 23, 55 Fig. 65. Half circle of kinematograph plate reduced. Fig. 66. 5 successive photographs enlarged, the first four, from below upwards, taken by magnesium light. (Sunrise March 23, 5.58 a.m). The lettered numbers, e.g. 1 a-ioa, indicate series of figures taken from the same flower-bud. The figures 1-64 were drawn natural size and reduced to f. 3 G 2 Hi / R. SCOTT SPARMANNIA AFRICANA. University Press, Oxford ! R. SCOTT SPARMANNIA AFRICANA. jrM of Eaton# ^l.XVIL PIMVIII. University Press, Oxford. R. SCOTT SPARMANNIA AFRICANA. Annals of Botany Vol. XV IT PI. XXXIX . R. SCOTT , P/40£. R. SCOTT. — SPARMANNIA APR I CANA. Morphological Notes. BY Sir W. T. THISELTON-DYER, K.C.M.G., C.I.E., F.R.S., Director , Royal Botanic Gardens , Kew. With Plate XL. X. A Proliferous Pinus Cone. T HE specimen described in this note has perhaps a little more than a scientific interest. It was brought from Spain by the late H. R. H. the Comte de Paris in 1894 and sent by him to me not many months before his death, which took place on September 8 of that year. Its history is given in the following letters: — Palacio de Villamanrique, Provincia de Sevilla (Espana), April 27, 1894. Sir, I have in my possession what I consider as a very curious botanical phenomenon, and I would gladly present it to the Kew Museum, or send it to you for inspection, if you thought it worth of it. It is a frondiferous cone of the Pinus Pinea , out of the upper end of which has grown a young tree just as a pine-apple grows out of the crown of this fruit. Generally these cones fall only after having thrown away their seeds. This one fell on the ground (how I do not know) with the seeds or almonds still encased in it. It was picked up in a large Pinar or pine forest which I own in this neighbourhood, by [Annals of Botany, Vol. XVII. No. LXVIII. September, 1903.] 780 Thiselton-Dyer —Morphological Notes. one of my keepers a day I was out shooting. The young tree was then about six inches long. The woodmen of this country say they never saw anything like it. I took the cone home and left it alone on a table, about the middle of February. It went on growing for a month, made a stem more than a foot long with three branches, and even threw out new shoots. About the end of March, although it was watered, it ceased to grow and dried, although the needles did not fall and preserve their colour. Will you kindly send your answer to Stowe House, Buckingham, where I shall be in a few weeks, as a letter sent to Spain would be too late to reach me. Believe me, &c., PHILIPPE COMTE DE PARIS. Stowe House, Buckingham, May 19, 1894. Dear Sir, I have just received your letter of yesterday, and I hasten to thank you for it. I send you at once the curious growth out of the cone of Pinus Pinea which I mentioned to you in my first letter. If it can be of any interest I shall be glad to present it to the Kew Museum. As I wrote to you, this cone was found on the ground in the Pinar de los Lobos on my estate of the Coto del Rey near Seville, by one of my keepers a day I was out shooting in February, 1894. The growth then was only six inches long and single, and quite fresh. I took it home and put it on a shelf in my study where it went on growing and dividing in branches for about a month. Then it suddenly stopped, dried up, and nothing could induce it to start again : very likely the stock of sap which the cone contained was exhausted. Believe me, &c., PHILIPPE COMTE DE PARIS. Stowe House, Buckingham, June 11, 1894. Dear Sir, I learn from your letter, with the greatest pleasure, that the botanical specimen which I had sent you a fortnight ago has been most fortunately discovered, and the foolish idea of the Thiselton-Dyer. — Morphological Notes. 781 railway expeditor in Buckingham who labelled the parcel con- taining this specimen as an empty box, has had no serious conse- quences. I only regret very much the trouble which this absurd mistake has caused you, and I beg to apologize for it. It would indeed have been very unfortunate if this curious and anomalous growth had been lost for ever under a heap of old empty boxes. I thank you very much for the interesting lecture given in your letter upon the physiological characters of pine-cones. What struck me most in that specimen is the following fact : when it was picked up it must not have been lying on the ground more than two or three weeks, perhaps less. The young single shoot was not six inches long. It went on growing very rapidly, throwing off branches and showing all the appearances of an ordinary strong and healthy branch, without being ever fed in any way. After about six weeks it had attained its present size, and then the growth suddenly stopped and the needles, losing their dark green appearance, began to wither. It was in vain that I put the cone in a wet cloth, nothing could restore life in it. This shows evidently that there was a certain quantity of sap in the cone sufficient to insure this anomalous growth up to a given size, and that when this store of food was exhausted the autonomous life of this . cone became extinct. Excuse me for making this remark, and believe me, &c., PHILIPPE COMTE DE PARIS. The total length of the specimen is 19^ inches. The figure is therefore reduced to rather more than a third. The cone belongs to the ‘ Stone Pine ’ (Pinus Pinea, L.). As is well known the seeds are edible, hence the Comte de Paris writes of them as ‘ almonds ’ : strung together they are sold in the market at Lisbon. Examples may be seen in the Kew Museum, where the specimen is also preserved. I have failed to find any record of terminal prolification in a Pinus cone, and Dr. Masters, F.R.S., who is an accepted authority on the Coniferae , kindly informs me that he knows of none. Normal cones of Pinus Pinea are usually about 6 inches long. That now described is only 3^ inches. It is there- fore a small cone. But as the apex of the largest scales 782 Thiselton-Dyer . — Morphological Notes . measures an inch across, which is the normal size, the smallness of the cone is due to its having fewer scales and not to its being immature. The morphological interpretation of the female cone in the Abietineae is a subject upon which the most divergent views have been held. As is well known a cone is composed of seminiferous scales (which become greatly enlarged in Pinus) and these are apparently axillary structures subtended by the primary reduced leaves of the axis of the cone, the so-called bract-scales. In Larix proliferation of the female cones is not uncommon. But the passage from cone to shoot is not, as in the present case, abrupt, but gradual. Masters has shown conclusively (Gardeners’ Chronicle, N.S., xvii. pp. 112, 113) that in such cases the bract-scales pass into ordinary foliage leaves with which they are serially continuous. The fact admits of no dispute and the interpretation is generally accepted. So far we seem to be on solid ground : whatever be the explanation of the seminiferous scale it is at any rate ‘ sub- tended 5 by the bract-scale, which is undoubtedly a modified foliar organ and is not seminiferous. This state of things is in sharp contrast to that which obtains in the Cycadeae. In a former note (Annals, xv. pp. 548-550) I have shown from the study of a proliferous Encephalartos , that the carpophylls or seminiferous scales are homologous with the ordinary foliage leaves and there- fore with the bract-scales in the Coniferae , as both belong to the primary axis. No one would I suppose now deny that the Gymnosperms stand in an intermediate position between the Phanerogams and the Cryptogams. Few things in vegetable morphology are more remarkable than the reluctance with which this has been admitted. Nothing can of course be simpler than the fundamental generalization which is applied to both. An Anther is a modified leaf which produces microsporangia: a Carpel is a modified leaf which produces macrosporangia. Of the latter T hiselton-Dyer . — Morphological Notes . 783 the carpophyll of Cycas is the simplest we know : we fold it like a sheet of note-paper, and we get an arrangement which does not differ essentially from a pea-pod. But in the majority of Phanerogams, a carpel of this simple type is lost sight of in the complexity of adaptive arrangements, and a subsidiary structure — the placenta — is called into existence to bear the ovules. It seems to me that the Gymnosperms having assisted us to grasp the generalized structure underlying the complex arrangements of the Phanerogams, we must use great caution in the attempt to find in the former the specialized structures developed in the latter. Nevertheless the history of Gymno- spermous morphology shows a constant attempt to bring it forcibly into line with that of Phanerogams. The most recent view as to the nature of the seminiferous scale in Abietineae proper is that of Goebel (Outlines of Classi- fication and Special Morphology, p. 328). He lays stress on the fact that in Abies ‘the seminiferous scale arises as a protuberance on the base of the so-called bract-scale and therefore is not axillary.’ I must confess, however, that vegetable morphology presents us with so many cases of similar dislocations that the mere fact taken alone does not strike me as of great importance. I am disposed to agree with Van Tieghem that it merely depends on ‘ intercalary growth ’ such as ‘ separates a dialypetalous corolla from a gamopetalous one.’ If this is the correct view, as I believe it to be, Goebel’s theory that ‘the seminiferous scale’ must ‘ be regarded as a placenta of large dimensions growing out of a carpellary leaf 1 seems to be without a valid argument to support it. And in Pinns , where the seminiferous scale is truly axillary, Goebel admits that it cannot be considered an outgrowth, though he still thinks it may be considered a placental growth. If the seminiferous scale is not a placenta or outgrowth from the bract-scale, which in that case would be a carpel, it must be some kind of foliar organ. Lindley was satisfied ‘ that the scales of the cones really are metamorphosed leaves ’ 784 Thiselton-Dyer . — Morphological Notes. (Vegetable Kingdom, 3rd ed. 22 7). And this view seemed to him conclusively supported by a monstrous cone of Picea excelsa figured by Richard (Memoire sur les Coniferes et Cycadees, 1. 12, f. 3). Unfortunately this was not a cone at all, but a ‘ false cone’ or gall. Schleiden, whose boisterous criticisms may still be studied with advantage, insisted that the seminiferous scale was the equivalent of an axillary bud : — ‘ l’ecaille, con- sideree par R. Brown comme un ovaire ouvert, n’est autre chose que le bourgeon axillaire de la feuille carpellaire, place sous l’ecaille, et, par cette raison seule, ne saurait etre un organe foliaire, parce que folium in axilla folii est chose sans exemple dans tout le monde vegetal (Ann. d. sc. nat., 2 e sdr., xii. 374). Schleiden’s theory was developed by Braun, Caspary, and at first Eichler : they regarded the seminiferous scale as a short axis which has coalesced with its two carpels ; Von Mohl as ‘a coherent structure formed of the leaves of an undeveloped branch.’ The latter view derives some support from the ingenious argument which Masters has founded on a proliferous cone of Sciadopitys, first figured in Veitch’s Manual of Coniferae (Gardeners’ Chronicle, 1 . c.). According to a note by Van Volxem in the same volume (p. 155) this is ‘the most common form in the neighbourhood of Yokohama.’ Masters finds that in this case the bract-scale remains un- changed, while the seminiferous scale is replaced by a normal ‘ leaf.’ He remarks that ‘ whatever be the nature of the so-called ‘leaf’ of Sciadopitys it must be essentially the same as that of the seed-scale of the Abietineae .’ The argument is, however, doubtful. Sciadopitys does not belong to the Abietineae proper, and its ‘leaf’ has itself been regarded as a shoot formed by the coalescence of a pair of leaves such as occur in Abietineae. Van Tieghem has adopted a view of which I have given an account in a note to Sachs’ Textbook (1st ed. pp. 453-4). He regards the seminiferous scale ‘ as the first and only leaf of an axis which undergoes no further development.’ This reconciles the views of Schleiden and Lindley. Thiselton-Dyer . — Morphological Notes. 785 The position, however, becomes more complicated when we consider the remarkable case of a monstrous cone of Pinus lemoniana (P. Pinaster), described by Parlatore, from the Gardens of the Royal Horticultural Society at Chiswick (Ann. d. R. Mus. di St. nat. di Firenze, 1884). In this the seminiferous scale is replaced by a limited branch or fascicle of ordinary foliage leaves. The facts: — ‘ dimostrano chiara- mente come ne conviene lo stesso Signor Eichler, che nell’ organo squamoso o squama interna, secondo ch’ egli lo chiama, delle Abietinee, debba scorgersi non un asse soltanto secondo Popinione di Schleiden, ne un carpello come comunemente si crede, ma un ramo raccorciato con gli organi fogliacei.’ An important paper by Stenzel (Nova Acta, xxxviii, 1876) I have not had the opportunity of seeing. But it has been carefully summarized by the late Professor McNab (Journ. Bot. 1877, pp. 26—7). It was based on abnormal scales of the spruce ( Picea excelsa , Lk.) in which the seminiferous scale was replaced by an axillary bud. ‘ The two lateral bud-scales . . . are well developed, hard, brown, with the margin irregular and quite of the texture of the scales of the cone. By further tracing these abnormal buds it is found that at last all trace of the bud except the two lateral bud-scales disappears, and these become soldered more or less completely. . . . Farther down, the scales show no trace of a suture, and pass into the ordinary bifid scales of the cone.’ The conclusion arrived at was that the fruit-scale of the spruce, and also of the other true Abietineae , consists of the first two leaves of a suppressed bud developed in the axil of a bract. This is in agreement with the view of Von Mohl (187 1 ). Latterly Eichler changed his views, according to a note in the Gardeners’ Chronicle (l.c. pp. 264-6). ‘In his opinion the seed-scale is only an excrescence from the outer scale or bract, so that the two really constitute one leaf, and the bud or branch in the axil of the bracts in proliferous cones are not to be considered as transformed seed-scales, but as axillary buds to the composite leaf.’ If this were the true explana- yS6 T hiselton-Dyer. — Morphological Notes. tion one would expect to find some trace of the seminiferous scale persisting, even' in the presence of an axillary bud. But it is clear that this is not the case. In the Abietineae with membranous cone-scales (possibly also in Sciadopitys ) it seems to me that the view of Von Mohl, supported by the researches of Stenzel, is probably correct, and that the seminiferous scale is complex in its origin. But I am not clear that this is the case when the cone is woody, as in Pinus. It does not follow because the seminiferous scale is replaceable by a fascicle of leaves that all potentially take part in its development. The general resemblance of a cone of Pinus to one, say, of Enceplialartos is obvious at a glance. In each case we have a ‘ carpophyll ’ enlarged above into an hexagonal apophysis with an ‘ umbo ’ on its external surface. However violent may seem the transformation, I have clearly demonstrated that the carpophyll in Enceplialartos is a modified leaf belonging to the primary axis: in the Abietineae it appears to me equally demonstrable that it belongs to a secondary one. As Van Tieghem has remarked : — 6 This establishes a fundamental distinction between Cycadeae and Coniferael But, as in Encephalartos , the umbo seems to me clearly the dilatation of the atrophied apex of a foliar organ. Returning to the specimen now described, I have already noticed that, unlike what takes place in the proliferous shoots of Larix , there is an abrupt discontinuity between the repro- ductive and vegetative regions of the axis. This reminds one in fact of Callistemon , where the same axis serves alternately one or the other purpose : an even closer analogy would be found in Cycas if the carpophylls were persistent. The explanation of the fact that a cone is not proliferous is to be found in physiological necessity. The upward stream of food is diverted and absorbed by the developing carpophylls, and the growing point of the cone is arrested in its further development practically by starvation. The upper semini- ferous scales share the same fate and become mere woody rudiments. Meanwhile the growth of the cone in diameter sets up a passive tension which would, by mechanical pressure, TJiiselt on-Dyer . — Morphological Notes. 787 in ordinary cases effectually suppress any extension of the growing point. It is, however, to be remarked that in Pinus Pinea the cone is often not quite symmetrical ; there is a sort of apical appendix, as if terminal growth were not relinquished without a struggle. I have already noticed that the cone now described is below the normal size. It may be supposed that the food-supply directed towards it was in excess of its needs. The growing point was therefore started into activity. That this was not, however, accomplished without a struggle is proved by the deep constriction between the shoot and the cone. The passive tension of the apex of the cone prevented any increase in the diameter of the shoot till it was entirely free from it. The age at which the specimen came into my hands had obliterated any trace of external morphological continuity between its two parts. But it seems impossible to shut one’s eyes to the fact that the fascicles of leaves in the upper part must correspond to the carpophylls or seminiferous leaves in the lower. One or two other points remain to be mentioned. Why the cone was shed, seeing that it was actively vigorous, is difficult even to conjecture. When first found the shoot was six inches long ; it is now sixteen : it therefore grew at least ten inches after separation from the parent tree. The cone is probably figured in about its normal position : the strong curvature of the shoot is no doubt due to geotropism. The shoot was entirely dependent on the cone for its supply of both constructive material and water. It is a striking illustration of the power possessed by rapidly-growing tissues of not merely diverting nutriment from others which are less active, but of actually robbing them. But in the absence of roots the supply was bound sooner or later to come to an end. Probably the actual cause of death was, notwithstanding the pains of the Comte de Paris, the failure of a water supply to maintain the transpiration current. Annals of Botany. Vol XVII. PI XL. THIS ELTON “DYER— PROLIFEROUS GONE OF PINUS PINEA. NOTES. THE COTYLEDONS OF GINKGO BILOBA AND CYCAS REVOLUTA. Mr. Lyon, in discussing the phylogeny of the coty- ledon in the journal Postelsia (1901), has come to the conclusion that the so-called cotyledons of the Pteridophyta and Gymnosperms, with” the probable exceptions of Ginkgo and the Cycads, are true foliage leaves. The foliar nature of the ‘ cotyledons ’ of Ginkgo and the Cycads would seem from this still open to discussion. The alternative would be the interpretation of these cotyledons as feeders, the term applied by Prof. Bower to the absorptive organs of the Gnetaceae. Apart from the obvious double structure of the absorptive organs in Ginkgo and Cycas, which clearly distinguishes them from the feeders of the Gnetaceae, and would suggest their foliar nature, there are other features which may, I think, be taken to indicate that they are much modified foliar organs. Among these characters one I have recently observed is the occurrence of stomata on these cotyledons. In Ginkgo the cotyledons are surrounded by endosperm but not fused with it. Their inner surfaces are closely pressed together so that each appears semi-circular in transverse section ; sometimes only the margins meet, and then the cotyledons appear almost crescentic in transverse section. Stomata are found chiefly on the upper surface, while in the foliage leaves they occur on the lower side only. This may be explained either by supposing those on the under surface of the cotyledons to have disappeared owing to the absorptive function of that part of the cotyledons, or, if we assume that the cotyledons were at a former period in the history of the plant expanded above ground, the stomata on the upper surface may have been protected by closing movements of the cotyledons similar to those of Cucurhita. [Annals of Botany, Vol. XVII. No. LXV III. September, 1903.] 790 Notes. The guard-cells, which are smaller than the other epidermal cells, lie flush with the surface of the cotyledon ; they contain large, deeply staining nuclei. In surface view they appear crescent-shaped, enclosing a small, round or slightly oval pore .in the centre (Fig. 29 A). In transverse section it is seen that the pore opens into a small intercellular space which in some cases appears to be filled with loose- celled tissue. The guard-cells are oval in transverse section and obliquely inclined towards one another at the surface, their walls are thicker than those of the neighbouring cells but do not seem to be cuticularized. In Cycas revoluta the cotyledons are much thicker and narrower than those of Ginkgo ; they are more closely connected with the surrounding endosperm and their inner flattened surfaces are fused together, so that the junction of the two can only be distinguished near the margin, where the epidermal layers are still marked out, and by the thickening of the cell-walls of a few smaller cells here and there in the central part. In spite of this very considerable alteration which the cotyledons have undergone stomata are still recognizable in a transverse section of the cotyledon. The guard-cells here are much smaller than the neighbouring cells, and of characteristic shape. They contain large, deeply staining nuclei, and their walls are very much cuticularized on what would be their outer surface if the cotyledons were not fused. A well-marked pore leads into an intercellular space below (Fig. 29 B). It is evident from the position of the stomata in Cycas revoluta that they cannot possess any functional value ; probably they only indicate an ancestral condition when the cotyledons came above ground and functioned as ordinary foliage leaves. In Ginkgo , however, where the cotyledons are not fused, there would be a layer of air between the two cotyledons, between which there often exists a considerable space, and here they might possibly have a respiratory function. At all events, whether functional or not, their presence suggests that at one time the cotyledons of Ginkgo were withdrawn from the testa and expanded above ground, as is the case in most Gymnospermous seedlings. There seems, therefore, good reason to regard the cotyledons of Cycadaceae and Ginkgoaceae as true foliage leaves, which have Notes . 791 become hypogeal like those of Araucaria brasiliana , A. imbricata and A. Bidwillii. A. Fig. 29. A. Portion of the upper surface of the cotyledon of Ginkgo, showing a stoma with distinct pore. B. Portion of a section across the fused cotyledons of Cycas. The two guard- cells of the stoma are distinctly separated and their outer walls are cuticularized. Cuticular thickening at other points indicates the line of junction of the two coty- ledons. GRACE WIGGLESWORTH. Owens College, Manchester. 3 H 792 Notes. THE ‘ EPIDERMOID AL * LAYER OF CALAMITE ROOTS — The bounding layer of young calamite roots consists of cells with thick outer membranes. These are in no way specially remarkable, being cells which have ‘ the structure of a thick-walled epidermis, and appear to correspond in all respects with the epidermoidal layer described by Olivier in many recent roots' 3 . As is seen from the published figures 1 2 they are much the same size as the cells of the cortex (diameter about *o8 mm.), and do not stand out from them in any very remarkable way, except in the thickness of the external wall. In foreign specimens of older roots a periderm of nine to twelve layers has been described by M. Renault 3 , but the outermost layer does not appear to have differed from the ones below it. No such definite periderm has been described for English roots. In the above 1 Williamson and Scott, Further Observations, II, Phil. Trans., 1895, p. 694. 2 loc. cit., PI. XV, Phot. 5, PI. XVII, Figs. 7 and 8. 3 Genre Astromyelon, Ann. des Sci. Geol., 1885, vol. xvii, Fig. 2, PI. VII. Notes. 793 quoted memoir 1 the authors draw attention to a section in which the outer layer appeared two cells in thickness, and which ‘ suggested that we have here a peridermic formation * even although the cells lacked the clear definition of a well-developed periderm. The object of this note is to place on record what appears to be an undoubted peridermic formation in roots from the lower coal-measures of England, which also show a highly specialized ‘ epidermoidal layer/ The slides from which the present descriptions and sketches have been taken are S. 4014 and 4015, from the series S. 4013-7, continued in S. 3556-8, in the general collection of the geological department of the British Museum (Nat. Hist.). The root appears to have had a diameter of about 15 mm., but it is impossible to be quite accurate as the pith is not well preserved, and the stele is somewhat compressed and split by stigmarian rootlets. The preservation of the inner and middle cortex is poor, but there is sufficient evidence of continuity between these layers and the outer cortex, which is crushed against the well-preserved ‘ epidermoidal layer/ continuous round the root, see Fig. 30. The individual epidermoidal cells are very large, ranging from -175 to -2 mm. in diameter, and considerably exceeding any other tissue in the root. The outer membrane of each cell is thick, and from it fibrous fragments project into the cell-cavity, Fig. 31 ; it is not possible to ascertain the minute structure of these fibres, and I am not aware of any similar appearance in recent plants that would throw light on their nature. x 100. Fig. 31. The epidermoidal cells appear to originate as the enlarged outer layer of the periderm, see Fig. 32 A and B, and it seems probable that they took the outermost position with some irregularity, as in most cases the linear arrangement of the periderm cells has been disturbed, 1 Will, and Scott, loc. cit. , Pl. XVII, Fig. 11, and p. 694. 794 Notes . and cells such as a in Fig. 32, A are common, where a periderm ceil below the outer layer is beginning to take on the epidermoidal characters ; this explains the lack of linear continuity between the periderm as such and the outer layer, as the enlarging cell pushes the others to one side. In Fig. 32, B the linear arrangement is not disturbed, and we also get the remains of a layer outside the present functional one. It appears, therefore, that, at least in the English specimens, when periderm formation takes place, the primary epidermoidal layer of the young root is replaced by the specialized outer layer of periderm which is irregularly reinforced from the cells beneath. M. C. STOPES. University College, London. ' Vol. XVII. No. LXV. January, 1903. Price 14s. ($3.50). Annals of Botany EDITED BY ISAAC BAYLEY BALFOUR, M.A., M.D., F.R.S. king’s BOTANIST IN SCOTLAND, PROFESSOR OF BOTANY IN THE UNIVERSITY. AND KEEPER OF THE ROYAL BOTANIC GARDEN, EDINBURGH D. H. SCOTT, M.A., Ph.D., F.R.S. HONORARY KEEPER OF THE JODRELL LABORATORY, ROYAL BOTANIC GARDENS, KEW AND WILLIAM GILSON FARLOW, M.D. PROFESSOR OF CRYPTOGAMIC BOTANY IN HARVARD UNIVERSITY, CAMBRIDGE, MASS., U.S.A. ASSISTED BY OTHER BOTANISTS Bonbon HENRY FROWDE, AMEN CORNER, E.C. CLARENDON PRESS DEPOSITORY, 116 HIGH STREET Printed by Horace Hart, at the Clarendon Press, Oxford . PAGE CONTENTS. Sargant, Miss E.— A Theory of the Origin of Monocotyledons, founded on the Structure of their Seedlings. With Plates I-VII, and ten Figures in the Text ...... i Darwin, F., and Pertz, Miss D. F. M— On the artificial Produc- tion of Rhythm in Plants. With a note on the position of maximum heliotropic stimulation. With four Figures in the Text 93 Salmon, E. S.— A Monograph of the Genus Streptopogon, Wils. With Plates VIII, IX, and X . . . . . .107 Marloth, R. — Some recent Observations on the Biology of Roridula. With a Figure in the Text 151 Sprague, T. A— On the Heteranthus Section of Cuphea (Lythraceae). With Plate XI .159 Barker, B. T. P.— The Morphology and Development of the Asco- carp in Monascus. With Plates XII and XIII . . . 167 Vines, S. H. — Proteolytic Enzymes in Plants 237 NOTES. Hill, A. W. — Notes on the Histology of the Sieve-tubes of certain Angiosperms 265 Crossland, C. — Note on the Dispersal of Mangrove Seedlings. With a Figure in the Text 267 Cavers, F. — Explosive Discharge of Antherozoids in Fegatella conica. With a Figure in the Text 270 FRITSCH, F. E. — Algological Notes. IV. Remarks on the periodical Development of the Algae in the artificial Waters at Kew . 274 Bower, F. O. — Note on abnormal Plurality of Sporangia in Lycopo- dium rigidum, Gmel. With a Figure in the Text . . , 278 NOTICE TO SUBSCRIBERS. The subscription-price of each volume is thirty shillings, payable in advance : the Parts, four in number, are supplied as they appear, post free to subscribers in the United Kingdom, and with a charge of is. 6 d. per annum for postage to subscribers residing abroad. The price of individual Parts is fixed at a higher rate. Intending subscribers should send their names, with subscription, to Henry Frowde, Oxford University Press Ware- house, Amen Corner, London, E.C. The subscription price of each volume for American subscribers is $12.00 net, payable in advance, postage 40 c. extra. Orders should be sent to Henry Frowde, Oxford University Press, American Branch, 91 and 93 Fifth Avenue, New York. As the earlier volumes of the Annals of Botany are becoming scarce, VoL I will only be sold as part of a complete set; and Parts will not as a rule be sold separately, after the publication of the volume to which they belong. A few extra copies of particular Parts at present remain on hand, for which special application must be made to the Editors, Clarendon Press, Oxford. NOTICE TO CONTRIBUTORS. Contributors in America should address their communications to Professor Farlow, Harvard University; and all other contributors, to the Editors, at the Clarendon Press, Oxford. Papers sent in with a view to publication must be type-written ; and the illustrative figures should be planned so as to properly fill a 4to or an 8vo plate. Attention to this will conduce to the rapid publication of the papers if accepted. Each contributor to the Annals of Botany is entitled to receive gratis twenty-five separate copies of his paper, and may purchase additional copies if he informs the Editors of his wishes in this respect when he returns corrected proofs. The price of these additional copies will depend upon the amount of text and the number of plates in the paper. ISSUED QUARTERLY. Vol. XVII. No. LXVI. March, 1903. Price 14s. ($3.50), Subscription for one year 30s. ($12.00). Annals of Botany EDITED BY ISAAC BAYLEY BALFOUR, M.A., M.D., F.R.S. KING’S BOTANIST IN SCOTLAND, PROFESSOR OF BOTANY IN THE UNIVERSITY AND KEEPER OF THE ROYAL BOTANIC GARDEN, EDINBURGH D. H. SCOTT, M.A., Ph.D., F.R.S. HONORARY KEEPER OF THE JODRELL LABORATORY, ROYAL BOTANIC GARDENS, KEW WILLIAM GILSON FARLOW, M.D. PROFESSOR OF CRYPTOGAMIC BOTANY IN HARVARD UNIVERSITY, CAMBRIDGE, MASS., U.S.A. ASSISTED BY OTHER BOTANISTS HENRY FROWDE, AMEN CORNER, E.C. CLARENDON PRESS DEPOSITORY, 116 HIGH STREET 1903 Printed by Horace Hart, at the Clarendon Press, Oxford. PAGE CONTENTS. Allen, C. E. — The Early Stages of Spindle-Formation in the Pollen- Mother-Cells of Larix. With Plates XIV and XV . Willis, J. C., and Burkill, I. H. — Flowers and Insects in Great Britain. Part II. Observations on the Natural Orders Dip- saceae, Plumbaginaceae, Compositae, Umbelliferae, and Cor- naceae, made in the Clova Mountains Miyake, K. — On the Development of the Sexual Organs and Fertiliza- tion in Picea excelsa. With Plates XVI and XVII Howard, A.— On some Diseases of the Sugar-Cane in the West Indies. With Plate XVIII ....... Hill, T. G., and Freeman, Mrs. W. G.— The Root-Structure of Dioscorea prehensilis. With Plate XIX and a Figure in the Text Arber, E. A. N.— On the Roots of Medullosa anglica. With Plate XX Thiselton-Dyer, Sir W. T.— Morphological Notes. IX. A Ka- Ianchoe Hybrid. With Plates XXI-XXIII . . 281 313 351 373 413 425 435 NOTES. Hemsley, W. B., and Rose, J. N. — Diagnoses Specierum Generis Juliania, Schlecht., Americae Tropicae 443 Hope, C. W.— Note to Article in the Annals of Botany, Vol. xvi, No. 63, September, 1902, on ‘ The “ Sadd ” of the Upper Nile-’ 446 NOTICE TO SUBSCRIBERS. The subscription-price of each volume is thirty shillings, payable in advance : the Parts, four in number, are supplied as they appear, post free to subscribers in the United Kingdom, and with a charge of ij. 6 d. per annum for postage to subscribers residing abroad. The price of individual Parts is fixed at a higher rate. Intending subscribers should send their names, with subscription, to Henry Frowde, Oxford University Press Ware- house, Amen Corner, London, E.C. The subscription price of each volume for American subscribers is $12.00 net, payable in advance, postage 40 c. extra. Orders should be sent to Henry Frowde, Oxford University Press, American Branch, 91 and 93 Fifth Avenue, New York. As the earlier volumes of the Annals of Botany are becoming scarce, Vol. I will only be sold as part of a complete set; and Parts will not as a rule, be sold separately, after the publication of the volume to which they belong. A few extra copies of particular Parts at present remain on hand, for which special application must be made to the Editors, Clarendon Press, Oxford. NOTICE TO CONTRIBUTORS. Contributors in America should address their communications to Professor Farlow, Harvard University; and all other contributors, to the Editors, at the Clarendon Press, Oxford. Papers sent in with a view to publication must be type-written ; and the illustrative figures should be planned so as to properly fill a 4to or an 8vo plate. Attention to this will conduce to the rapid publication of the papers if accepted. Each contributor to the Annals of Botany is entitled to receive gratis twenty-five separate copies of his paper, and may purchase additional copies if he informs the Editors of his wishes in this respect when he returns corrected proofs. The price of these additional copies will depend upon the amount of text and the number of plates in the paper. Vol. XVII. No. LXVII. June, 1903. Price 14s. Annals of Botany EDITED BY ISAAC BAYLEY BALFOUR, M.A., M.D., F.R.S. king’s BOTANIST IN SCOTLAND, PROFESSOR OF BOTANY IN THE UNIVERSITY AND KEEPER OF THE ROYAL BOTANIC GARDEN, EDINBURGH D. H. SCOTT, M.A., Ph.D., F.R.S. HONORARY KEEPER OF THE JODRELL LABORATORY, ROYAL BOTANIC GARDENS, KEW AND WILLIAM GILSON FARLOW, M.D. PROPESSOR OF CRYPTOGAMIC BOTANY IN HARVARD UNIVERSITY, CAMBRIDGE, MASS., U.S.A. HENRY FROWDE, AMEN <^iAiviLiwwiN PRESS DEPOSITORY, 116 HIGH STREET 1903 Printed by Horace Hart, at the Clarendon Press, Oxford. PAGE CONTENTS. Oliver, F. W.— The Ovules of the older Gymnosperms. With Plate XXIV and a Figure in the Text . . . . .451 Davis, B. M.— The Origin of the Archegonium. With two Figures in the Text 477 Tansley, A. G., and Chick, Miss E. — On the Structure of Schizaea malaccana. With Plates XXV and XXVI and a Figure in the Text 493 Boodle, L. A. — Comparative Anatomy of the Hymenophyllaceae, Schizaeaceae and Gleicheniaceae. IV. Further Observations on Schizaea. With three Figures in the Text . . . .511 Willis, J. C., and Burkill, I. H.— Flowers and Insects in Great Britain. Part III. Observations on the most Specialized Flowers of the Clova Mountains 539 Dale, Miss E. — Observations on Gymnoascaceae. With Plates XXVII and XXVIII . . 571 Vines, S. H. — Proteolytic Enzymes in Plants (II) . . . 597 NOTES. Pearson, H. H. W.— The Double Pitchers of Dischidia Shelfordii, sp. nov 617 Bower, F. O.— Studies in the Morphology of Spore-producing Members. No. V. General Comparisons, and Conclusion . 618 Oliver, F. W., and Scott, D. H. — On Lagenostoma Lomaxi, the Seed of Lyginodendron 625 NOTICE TO SUBSCRIBERS. The subscription-price of each volume is thirty shillings, payable in advance : the Parts, four in number, are supplied as they appear, post free to subscribers in the United Kingdom, and with a charge of is. 6d. per annum for postage to subscribers residing abroad. The price of individual Parts is fixed at a higher rate. Intending subscribers should send their names, with subscription, to Henry Frowde, Oxford University Press Ware- house, Amen Corner, London, E.C. As the earlier volumes of the Annals of Botany are becoming scarce, Vol. I will only be sold as part of a complete set; and Parts will not as a rule be sold separately, after the publication of the volume to which they belong. A few extra copies of particular Parts at present remain on hand, for which special application must be made to the Editors, Clarendon Press, Oxford. NOTICE TO CONTRIBUTORS. Contributors in America should address their communications to Professor Farlow, Harvard University; and all other contributors, to the Editors, at the Clarendon Press, Oxford. Papers sent in with a view to publication must be type-written ; and the illustrative figures should be planned so as to properly fill a 4 to or an 8vo plate. Attention to this will conduce to the rapid publication of the papers if accepted. Each contributor to the Annals of Botany is entitled to receive gratis twenty-five separate copies of his paper, and may purchase additional copies if he informs the Editors of his wishes in this respect when he returns corrected proofs. The price of these additional copies will depend upon the amount of text and the number of plates in the paper. kfff- ' ■ ' Yol. XVII. No. LX VIII. September, 1903. Price 14s. Annals of Botany EDITED BY ISAAC BAYLEY BALFOUR, M.A., M.D., F.R.S. king’s BOTANIST in SCOTLAND, PROFESSOR OF BOTANY IN THE UNIVERSITY. AND KEEPER OF THE ROYAL BOTANIC GARDEN, EDINBURGH D. H. SCOTT, M.A., Ph.D, F.R.S. HONORARY KEEPER OF THE JODRELL LABORATORY, ROYAL BOTANIC GARDENS, KEW WILLIAM GILSON FARLOW, M.D. PROFESSOR OF CRYP.TOGAMIC BOTANY IN HARVARD UNIVERSITY, CAMBRIDGE, MASS., U.S.A-. ASSISTED BY OTHER BOTANISTS Uondott HENRY FROWDE, AMEN CORNER, E.C. CLARENDON PRESS DEPOSITORY, 116 HIGH STREET 1903 Printed by Horace Hart, at Ike Clarendon Press, Oxford . CONTENTS. PAGE Fritsch, F. E. — Further Observations on the Phytoplankton of the River Thames . .631 Two Fungi, parasitic on species of Tolypothrix (Resticularia nodosa, Dang, and R. Boodlei, n. sp.). With Plate XXIX .649 Campbell, D. H.— Studies on the Araceae. The Embryo-sac and Embryo of Aglaonema and Spathicarpa. With Plates XXX, XXXI, and XXXII . . ....... 665 Gwynne-Vaughan, D. T. — Observations on the Anatomy of Soleno- stelic Ferns. Part II. With Plates XXXIII, XXXIV, and XXXV ..... 689 Hemsley, W. Botting— On the Genus Corynocarpus, Forst. With Descriptions of two new Species. With Plate XXXVI, and two Figures in the Text . 743 SCOTT, Rina.— On the Movements of the Flowers of Sparmannia africana, and their Demonstration by means of the Kinemato- graph. With Plates XXXVII, XXXVIII, and XXXIX. . 761 Thiselton-Dyer, Sir W. T.— Morphological Notes. X. A Proli- ferous Pinus Cone. With Plate XL 779 NOTES. Wigglesworth, Miss G— The Cotyledons of Ginkgo biloba and Cycas revoluta. With a Figure in the Text .... 789 Stopes, Miss M. C. — The ‘ Epidermoidal ’ layer of Calamite roots. With three Figures in the Text. . . , . . 792 NOTICE TO SUBSCRIBERS. The subscription-price of each volume is thirty shillings, payable in advance : the Parts, four in number, are supplied as they appear, post free to subscribers in the United Kingdom, and with a charge of is. 6d. per annum for postage to subscribers residing abroad. The price of individual Parts is fixed at a higher rate. Intending subscribers should send their names, with subscription, to Henry Frowde, Oxford University Press Ware- house, Amen Corner, London, E.C. As the earlier volumes of the Annals of Botany are becoming scarce, Vol. I will only be sold as part of a complete set; and Parts will not as a rule be sold separately, after the publication of the volume to which they belong. A few extra copies of particular Parts at present remain on hand, for which special application must be made to the Editors, Clarendon Press, Oxford. NOTICE TO CONTRIBUTORS. Contributors in America should address their communications to Professor Farlow, Harvard University; and all other contributors, to the Editors, at, the Clarendon Press, Oxford. Papers sent in with a view to publication must be type-written \ and the illustrative figures should be planned so as to properly fill a 4I0 or an 8vo plate. Attention to this will conduce to the rapid publication of the papers if accepted. Each contributor to the Annals of Botany is entitled to receive gratis twenty-five separate copies of his paper, and may purchase additional copies if he informs the Editors of his wishes in this respect when' he returns corrected proofs. The price of these additional copies will depend upon the amount of text and the number of plates in the paper.