Studies in the Indian Middle Gondwana Flora: 1. On Dicroidium from the South Rewa Gondwana Basin

Abstract

The structure of the epidermal cells of three species of Dicroidium, viz. D. odontopteroides (Morr.), D. sp. cf. D. feistmanteli (Johnston) and D. hughesi (Feist.) is for the first time described from the Triassic (Mid. Gondwana) rocks of the South Rewa Gondwana basin. Of these, D. sp. cf. D. feistmanteli is a new record. The epidermal structure, as far as known, favours the view that the two genera Dicroidium and Thinnfeldia are distinguishable. The epidermal structure of D. hughesi now conclusively proves that the generic name Danaeopsis originally used by Feistmantel for these fronds is unwarranted. The evidence as a whole strongly suggests that like the other Gondwanaland components, the Triasso-Rhaetic Gondwanas of India contain what should be recognized as a Dicroidium flora. It is further suggested that this flora, with Dicroidium as its characteristic genus, constitutes the Indian Midlle Gondwana flora.