Classification of the Gondwanas:
The classification of Indian Gondwanas is a matter of controversy.
G. de Cotton (1917) and Fox (1931) divided the Gondwana system into two major
divisions. Lower Gondwana (Lower Permian to Lower Triassic) and Upper
Gondwana (M. Triassic to L. Cretaceous) which are characterised by Clossopteris
and Ptilophyllum floras, respectively.
Feistmantel (1876) and Vredenburg (1910) proposed a three-fold classification of
Gondwana: Lower, Middle and Upper Gondwanas which are correspondingly
equivalent to the Permian, Triassic and Jurassic. All the localities containing
Lower Gondwana fossils, but bearing the lithological characteristics of the Upper
Gondwanas such as Panchet, Pachmari, Parsona, Maleri etc. are retained in the
Middle Gondwana.
The Middle Gondwana is characterised by Dicroidium flora, present in between
the Glossopteris and Ptilophyllum floras. Subsequently, most of the
palaebotanists supported the three-fold division of Gondwana.
The sub-divisions of Gondwana system are further divided into various series and
stages. There is no controversy regarding the division of Gondwana up to series.
However, the controversy arises at the level of stages and horizons. The flora of
Gondwana is arranged with reference to the time scale which begins with the
Talchir and extends up to the Bansa, Pariwar and Bhuj Formations.
Lower Gondwana:
This division shows predominance of the Glossopteris flora, during Permian
period, in which the Talchir, Karkarbari, Barakar, Barren measures Raniganj,
Motur, Hingir and Bijori Formations are included. Some elements of this division
continues till the Middle Triassic.
1. Pteridophytes:
(i) Equisetales : Schizoneura, Phyllotheca, Stellotheca.
(ii) Sphenophyllales: Sphenophyllum, Rani- ganjia, Trizygia.
(iii) Lycopodiales : Cydodendron.
(iv) Filicales : Gondwanidium, Pecopteris, Sphenopteris, Angiopteridium, etc.
2. Gymnosperms:
(i) Glossopteridales : Gangamopteris, Glossopteris, Rubidgea, Rhabdotaenia,
Vertebraria, Scutum, Ottokaria, Glosso- theca, etc.
(ii) Cycadales: Pseudoctenis, Taeniopteris.
(iii) Cordaitales : Noeggerathiopsis, Eury- phyllum, Cardiocarpus, Samaropsis.
(iv) Ginkgoales : Psygmophyllum, Ginkgo- phyton.
(v) Coniferales : Buriadia, Barakaria, Dadoxylon, Araucareoxylon, Agathoxylon,
Damudoxylon etc.
Middle Gondwana:
This is characterised by the accession of Dicroidium and declining of Glossopteris
flora (mixed flora) at the beginning of Triassic which extends up to the Upper
Triassic with dominance of Dicroidium flora. In this division, Panchet, Kamthi,
Pachmari, Maleri, Parsora, Bagra, Tiki, etc. Formations have been included.
Pteridophytes:
(i) Equisetales : Schizoneura.
(ii) Calamitales : Neo-Calamites.
(iii) Filicales : Pecopteris, Sphenopteris, Marianopteris Cladophlebis.
2. Gymnosperms:
(i) Glossopteridales : Glossopteris, Macro- taeniopteris, Vertebraria,
Dictyopteridium.
(ii) Corystospermales : Dicroidium.
(iii) Cycadales: Pseudoctenis, Taeniopteris.
(iv) Cycadeoidales : Pterophyllum, Zamites, Podozamites.
(v) Cordaitales : Neoggerathiopsis, Cardio- carpus, Samaropsis.
(vi) Coniferales : Araucarites.
Mid Gondwana flora
Upper Gondwana
This is characterised by the arrival of Ptilophyllum flora till the end of Gondwana
era, ranging from Jurassic to Lower Cretaceous, in which Dubrajpur, Rajmahal,
Kota, Jabalpur, Gangapur, Shivganga, Bhuj, Pariwar, etc., Formations are
conveniently included.
There is overlapping of the three distinct floras where the elements of the dying
flora crawl for some time amongst the evolving flora, thus, showing the floral
continuity throughout the Gondwana period. So, there is a gradual decline of one
flora with the simultaneous evolution of the other, both in number of individuals
and species. Even in a single flora, there is specific delimitation where certain
species characterise the smaller units of bigger sub-divisions.
Lower Gondwana flora
Flora of upper Gondwana;
1. Pteridophytes:
(i) Lycopodiales : Lycopodites.
(ii) Isoetates : Isoetites.
(iii) Equisetales: Equisetites.
(iv) Filicales : Phlebopteris, Marattiopsis, Gleichenites, Sphenopteris, Osmundites,
Cladophlebis, Cyclopteris.
2. Gymnosperms:
(i) Corystospermales: Dicroidium, Pachypteris, Cycadopteris.
(ii) Cycadales : Niissonia, Taeniopteris, Macrotaeniopteris, Pseudoctenis.
(iii) Cycadeoidales : Pterophyllum, Ptilo- phyllum, Bucklandia Weltrichia,
Zamites, Podozamites, Otozamites, Williamsonia, Cycadeoidea, Anomo- zamites,
Sahnioxylon.
(iv) Caytoniales : Sagenopteris, Caytonia, Caytonanthus.
(v) Pentoxylales : Nipaniophyllum, Carnoconites, Pentoxylon.
(vi) Cordaitales : Neoggerathiopsis, Cardio- carpus, Samaropsis.
(vii) Coniferales : Dadoxylon, Stachyotaxus, Elatochadus, Nipaniostrobus,
Sitholeya, Indophyllum, Pagiophyllum, Brachyo- phyllum, Araucarites.
(viii) Ginkgoales : Baiera, Ginkgoites.
(ix) Taxales : Taxaceoxylon, Torreyites, Taxites.
Upper Gondwana Flora
