Nord. J. Bot.

- Section of tropical taxonomy

New species of Euphorbia subgenus Tirucalli (Euphorbiaceae)

from Somalia and Oman
Susan Carter

Carter, S. 1992. New species of Euphorbia subgenus Tirucalli (Euphorbiaceae) from

Somalia and Oman. - Nord. J. Bot. 12: 675-679. Copenhagen. ISSN 0107455X.

A small shrub, Euphorbia bariensis related to E. arbuscula. a sturdy shrub. E.

pachyclada related to E. consobrina and E. nubica, and one with conspicuous bracts.
E. papilionum related to E . cameronii, are described as distinctive new endemic
species from northeast Somalia. A new' endemic. E. dhofarensis related to E. Iaricu.
is also described from the Dhofar region of Oman.

S. Carter, Royal Botanic Gardens, Kew, Richmond. Surrey TW9 3 A B , England

Species nova affinis E. arbuscufae Ba1f.f. sed habitu

Introduction fruticuloso compacto, ramis tenuioribus brevioribus
Euphorbia subgenus Tirucalli (Boiss.) S . Carter (1985) confertis, cyathiis minoribus, capsulis minoribus et bre-
is characterized by succulent cylindrical branches, small viter pedicellatis, seminibus ovoideis differt. - Fig. 1
quickly deciduous leaves, prominent leaf-scars, ex- A-E .
serted capsules and carunculate seeds. Within these pa-
rameters - at least in east and northeast Africa - are two Small shrub to 90 cm high, with compact branching;
well-defined groups of species, which have not so far branches fleshy, with a thick waxy coating; young
been formally separated. One is principally Madagas- growth tomentose, with curled orange-brown hairs
can, but closely associated with E. tirucaffiL. itself from which soon fall off. Leaves sessile, ovate, 3 x 1 .5 m m ,
the African mainland. Characteristic features are glan- fleshy, tomentose, recurved, soon deciduous; glandular
dular stipules, small scarious bracts and tightly con- stipules minute, brown. Cymes clustered 3-5 at the
gested inflorescences. It includes here the newly de- branchlet apices, subsessile, I-2-forked, the whole
scribed E. huriensis, related to the Socotran species E. cyme densely tomentose; bracts rounded, 1 x 1.5 mm.
arbuscula. The other group contains species more clasping the cyathia. Cyathia 2 x 2 mm, with cup-
closely related to the South African E. rnauritanica L . , shaped involucres; glands 5, quite separate, transversely
with pseudo-umbellate inflorescences, leafy bracts and elliptic, 0.5 x 1 m m , red; lobes 5 , rounded, 0.5 x 0.5
no stipules, but with the leaf-scars becoming callose, m m , margins ciliate. Male flowers: bracteoles spath-
very prominent and apparently glandular. Outside Ma- ulate, 1.5 m m long, apices plumose; stamens not seen.
dagascar it forms the larger group, with three new spe- Female flower: perianth obvious as a 3-lobed rim below
cies endemic in Somalia described in this paper. the tomentose ovary; styles 2 m m long, joined to almost
halfway, with recurved distinctly bifid apices. Capsule
just exserted on a thickened pedicel 2 m m long, sub-
Euphorbia bariensis S. Carter sp. nov globose, 5.5 X 5 mm, indistinctly 3-lobed, reddish
brown. Seeds ovoid, 2.8 X 1.8 mm, with pointed apex
Type: Gillett & Watson 23370, Somalia, Bari Region, 80 km
NE of Eil, 1 km from cliffs, 8"30'N, 50"17'E, 11 Jun 1981 (K flattened on the ventral side, smooth, pinkish grey;
holotype, EA, MOG isotypes). caruncle 1 m m across, yellow. - Fig. 1 A-E.

Accepted 6-2- 1992

0 NORDIC JOURNAL OF BOTANY
NORD. J. BOT. 12: 675-679

Nord. J . Bot. 12 ( 6 ) (1YY2) 675

 (991

Fig. 1. Species of Euphorbia. - A-E: E. buriensis. A: Habit, X 0.75. - B: Leaf, X 4.5. - C: Branch apex, x 4.5. - D: Cyathium
with immature fruit, x 4.5. - E: Seed, X 6.- F-I: E. puchycluda. F: Habit, X 0.75. - G : Fruiting cyathium, x 4.5. - H: Zapsule, x
4.5. - I: Seed, x 6. - A from Lavranos & Carter et al. 24740, B-C from Gillett & Watson 23500, D-E from Gillett & Watson
23370, F-I from Lavranos & Carter et al. 24719.

676 Nord. J . Bot. 12 ( 6 ) (1992)

Distribution and habitat. E. bariensis favours rocky seen. Cymes congested at the branchlet apices in 3-
limestone slopes of northeast Somalia, with sparse low branched umbels surrounding a central bisexual cyath-
Commiphora and mixed scrub at altitudes of 11G1340 ium, with rays 2-6 mm long; bracts ovate, sessile, 4 x
m. The extreme northeast corner of Somalia is known 3.5 mm. Cyathia 4.5 x 7-8 mm, with cup-shaped in-
for a number of endemic species having a direct link volucres; glands 4, o r 5 4 on the central cyathium,
with the flora of Socotra. E. bariensis provides another spreading, separate, 2.5 x 3 mm; lobes 5 , 1 x 1.5 mm,
example, with a limited distribution in Bari Region, and deeply notched, margin ciliate. Male flowers: bracteoles
its nearest relative being E. arbuscula Balf.f., an en- many, 3.5 mm long, deeply laciniate, with plumose
demic of Socotra. This latter species has closest affin- apices; pedicels 4 mm long; filaments 1.5 mm long.
ities with a group which has proliferated in Madagascar Female flower: ovary glabrous; styles 2.5 mm long,
and is closely related t o E . tirucalli L., the only species joined at the base, then spreading with shortly bifid
hitherto known to be indigenous on the African main- rugulose apices. Capsule just exserted on a slightly re-
land north of Zimbabwe and Mozambique. curved pedicel 6 mm long, very obtusely 3-lobed to
subglobose, 7 X 9 mm, tinged with red. Seeds ovoid, 3
Remarks. E . arbuscula forms a large shrub o r small tree x 2.75 mm, shallowly tuberculate, pale brown; caruncle
2-4 m high, with thick fleshy branches. Its cyathia are 1.5 mm across. - Fig. 1 F-I.
about 4 mm in diameter, producing distinctly 3-lobed
capsules to 1 cm in diameter, well exserted from the Distribution and habitat. E. pachyclada occurs on rocky
involucre on erect pedicels about 1 cm long. The variety limestone slopes with very sparse scrub vegetation, at
montana Ba1f.f. appears to produce slightly smaller cap- altitudes of 1W1100 m. This sturdy shrub appears to be
sules about 8 mm in diameter on pedicels 5 mm long, endemic to the rugged limestone mountains in the ex-
and with ovoid instead of subglobose seeds. E. barien- treme northeast of Somalia. As well as specimens from
sis, in contrast, is a small compactly branched shrub the two localities cited here, it has also been recorded
3 C 9 0 cm high, with thinly fleshy branches. Its cyathia from the top of the escarpment 8 km west of Bargal
are only half the size, but are similarly produced in tight (Carter, photo only).
clusters at the branchlet apices, and are also densely
tomentose. Capsules, however, are considerably Remarks. The species is clearly a member of a distinct
smaller and are only just exserted from the involucres. group occurring in Africa and the Arabian Peninsula,
Seeds most closely match those of E . arbuscula var. characterized by cylindrical succulent green branches
montana, but again, are smaller. from which the leaves are quickly deciduous leaving
Male flowers of the new species have not been seen. callose scars, and by simple pseudo-umbellate cymes.
It is quite possible that, like E. arbuscula and also E. Its inflorescence is compact, with very short rays and
tirucalli, cyathia on each plant have a tendency towards small cyathia, similar to those of E. consobrina, de-
the development of either male or female flowers, al- scribed from the Red Sea Hills of Sudan. Its erect
though E. tirucalli, at least, is not completely dioecious. compact habit forming a small shrub, is also similar, but
its branches are very much thicker. Its capsules also
Collections other than type. Somalia. Bari Region: Galgallo, 64 differ in being larger and very obtusely 3-lobed to al-
kni SW of Bosaso, 10 Jan 1973, Bally & Melville 15843 (K); most subglobose, rather than distinctly 3-lobed.
Ah1 Mescat Mts, 10"SS'N, 49"26'E, 18 Jun 1981, Gillet &
Watson 23500 (EA, K); 9 km W of Bargal, I1"17'N, 51"01'E, Another close relative, E. nubica described from Eri-
17 Nov 1986, Lavranos & Carter et al. 24740 (K, MOG). trea, usually has a more straggling o r subscandent habit,
forming a considerably larger shrub, at least as the
species is understood in Somalia (in Eritrea it appears to
Euphorbia pachyclada S. Carter sp. nov. possibly lack the subscandent habit). Branches of the
Type: Lavranos & Carter et al. 24719, Somalia, Bari Region,
new species, and especially the much shorter ultimate
Tug Yibirti, 38 km S of Bargal, 11"01'N, 51"0S'E,15 Nov 1986 branchlets bearing the more compact cymes, are thicker
(K holotype, EA isotype). in comparison. Cyme-branches are also very much shor-
ter, but the cyathia, capsules and seeds are comparable
Species nova affinis E. consobrinae N. E. Br. sed ramis in size, shape and surface sculpturing.
multo crassioribus, bracteis involucrorum caducis, cap-
sulis subglobosis majoribus, et affinis E . nubicae N . E. Colkcfion orher than type. Somalia. Sanaag Region: Galgallo,
64 km SSW of Bosaso, 10 Jan 1973, Bally & Melville 15845
Br. sed habitu breviore, ramulis erectis crassioribus,
(K).
cymis compactis, pedunculis cyathiorum multo breviori-
bus distinguitur. - Fig. 1 F-I.

Glabrous shrub 1-1.5 m high, with erect compact Euphorbia papilionum S. Carter sp. nov.
branching; branches succulent, yellowish green, 1-1.5 Type: Thulin & Warfa 6098, Somalia, Bari Region, Al Miskat
cm thick, sparsely covered with callose brown leaf- Mts, between Toh and Bahaya, 1I018-24'N, 49"49-50'E, 26
scars, ultimate branchlets 3-10 mm long. Leaves not Nov 1986 (K holotype, UPS isotype).

Nord. J. Bot. 12 ( 6 ) (19Y2) 677

Fig. 2. Species of Euphorbia. - A-B: E. papilionurn - A:Habit, X 0.75. - B: Cyathium, with bracts, X 4.5. - C-F: E. dhofarensis.
C: Habit, x 0.75. - D: Cyathium, x 4.5. - E: Capsule, X 4.5. - F: Seed, X 4.5. - A-B from Thulin & Warfa 6098, C-F from Miller
7245.

678 Nord. J . Bot. 12 ( 6 ) (1992)

Species nova affinis E . cameronii N. E. Br. sed habitu seminibus rugosis demum cinereo-brunneis distinguitur.
breviore. axillis et cicatricibus foliorum sine glandulis, - Fig. 2 C-F.
bracteis cyathiorum minoribus xanthochromis non al-
bis, cyathiis minoribus, glandulis involucrorum 4 lunatis Glabrous much-branched succulent shrub to 50 cm
differt. - Fig. 2 A-B. high; branches fleshy, cylindrical, 5-10 mm thick, pale
glaucous green, leafless on the specimens seen but with
Compact densely branched shrub 0.5-1 m high; very prominent spirally arranged leaf-scars. Leaves lan-
branches succulent, green, ca. 5 mm thick, marked with ceolate, ca. 5 X 2 mm (only a few seen); stipules mod-
callose leaf-scars. Leaves sessile, ovate-lanceolate, 8-12 ified as large (0.5 mm in diam.) persistent blackish
x 3 4 mm, quickly deciduous; stipules absent. Cymes in knob-like glands on either side of the leaf-scar. Cymes
terminal 2-3-branched umbels, with rays ca. 5 mm long, terminal and axillary, I-several times forked at the
or reduced to a solitary subsessile cyathium; bracts branch apices; bracts ovate, 3 X 1.5 mm, margin cili-
ovate. 8 x 7 mm, yellow, conspicuous, apparently per- olate. Cyathia ca. 2.5 x 4 mm with funnel-shaped in-
sistent. Cyathia 3 x 6.5 mm, with cup-shaped invo- volucres, reddish on the outside; glands 5 , transversely
lucres; glands 4, 2 x 2.5 mm, rather irregularly cres- elliptic, ca. 1 x 2 mm, green becoming red, separate;
cent-shaped, spreading, yellow; lobes 5, rounded, 1.3 x lobes 5, transversely oblong, 0.8 x 1.2 mm, margin
1 . S mm, margin denticulate, ciliate. Male flowers: brac- toothed, ciliolate. Male flowers: bracteoles ligulate,
teoles 2.5 m m long, deeply laciniate, apex plumose; deeply divided, pubescent; pedicels 2.5 mm long; fil-
pedicels 3 mm long; filaments 1 mm long. Female aments 0.8 m m long. Female flower: ovary glabrous;
flower: ovary glabrous, 3-lobed, pedicellate; styles 5 styles 2.5 mm long, joined for I m m with distinctly bifid,
mm long, joined for 2 mm, then spreading, with dis- spreading, thickened and flattened apices. Capsule on a
tinctly bifid apices. Capsule and seeds not seen. -Fig. 2 thickened pedicel 1 mm long, subglobose, ca. 7 X 7
A-B. mm, green becoming red. Seeds conical with truncate
base, obscurely 4-angled, 4 X 3 mm, surface rugose.
Distribution and habitat. E. papilionum is known only reddish buff becoming dark greyish brown, whitish and
from the one location, where it occurs on stony lime- roughened at the ventrally flattened apex. - Fig. 2 C-F.
stone slopes at an altitude of 1300 m.
Distribution and habitat. E. dhofarensis appears to be
Remarks. A diagnostic feature of E. cameronii is the endemic to the Dhofar region of Oman, where it occurs
row of tiny glands which develop in the leaf-axil and are in stony wadis around the lower slopes of the mountains
prominent around the upper edge of the leaf-scar. at altitudes between 50 and 650 m.
These glands are absent in this related new species. The
large involucral bracts of E. cumeronii are white, but Remarks. This new species forms a smaller shrub than is
those of E. pupilionurn are much smaller and bright usual with its relative E. lurica, with apical branching
yellow, together with the apical leaves surrounding the more spreading and less strictly erect. At least from the
cymes. The cyathia of this new species are also smaller, evidence of dried specimens, its branches appear to be
with four instead of five distinctive crescent-shaped yel- thicker. Leaf-scars are also more prominent and closer
low glands. Styles, however, are very similar, joined in together, and the glandular stipules especially are con-
an obvious column at the base, with spreading bifid siderably more conspicuous. Other significant differ-
apices. Capsules have not been seen, but the ovary is ences are found in its fruit. Its capsules are entirely red
distinctly 3-lobed. The significant characters of the yel- at maturity, instead of buff-coloured with purplish lines
low bracts, crescent-shaped glands and long styles, along the sutures, a feature characteristic of E. larica.
leave no doubt as to its specific status. When the type Finally, its seeds are quite distinct, with a rugose surface
collection was made, shrubs were in full bloom and which is pale reddish buff becoming dark greyish
covered in butterflies (Junonia limnoria limnoria brown, instead of smooth and black.
(Klug)), an unusual pollinator for Euphorbia, from
which the specific epithet was derived. Collections other rhan type. Oman. 25 km S of Thamrait on
Salalah road. 15 Sep 1984, Miller 6058 (E, K); just N of Jabal
Qara, 29 Jut 1985, Miller 7162 (E, K); Al Ayun. 17"17'N,
53"52'N, 8 Oct 1977. Radcliffe-Smith 5412 (K).
Euphorbia dhofarensis S. Carter sp. nov. Acknowledgements - Grateful thanks are due to A. Radcliffe-
Type: Miller 7245, Oman, E of Mirbat, wadi NE of Jaffa, 4 Smith for checking the Latin diagnoses. and to Margaret Tebbs
Aug 1985 ( K holotype, E isotype). for the illustrations.

Species nova affinis E. luricae Boiss. sed ramis crassiori-

bus non strictis, cicatricibus foliorum et glandulis stip-
ularibus valde prominentibus, capsulis omnino rubris,
Reference
Carter. S. 1985. New species and taxonomic changes in Eu-
phorbia from East and Northeast tropical Africa and a new
species from Oman. - Kew Bull. 40: 809-825.
43 Nord J Bot. I? ( 6 )(1992) 679