Reinvestigation of the coniferophyte morphospecies Buriadia heterophylla Seward and Sahni, with reinterpretation of vegetative diversity and putative seed attachments

Abstract

The Gondwana coniferophyte Buriadia heterophylla Seward and Sahni is reinvestigated from newly discovered material in eastern India, from previously described specimens of Buriadia florinii Maithy, and from specimens of B. heterophylla and Birsinghia florinii Pant, Nautiyal and Chaturvedi that previously were described as having attached seeds. Vegetative morphology and cuticular features for all of these Permian specimens from India conform to unimodal ranges of variation, and are reinterpreted as a single species. Horned seeds are commonly associated with the vegetative remains at most localities, but re-examination of specimens previously described as having attached seeds reveals that no seeds are preserved in organic connection to shoots. All of the specimens of vegetative remains are recognized as belonging to a single morphospecies, B. heterophylla Seward and Sahni that consists of compressed leafy shoots displaying distinct cuticular features as well as larger stems with some wood anatomy. The reproductive structures of B. heterophylla are unknown.