Pteridosperms from the Lower Carboniferous of South Urals, Russia.

Rich pteridosperm collection from the Visean (Mississippian, Lower Carboniferous) of the South Urals, Russia, was studied. A brief review of previous plant findings from the Lower Carboniferous of the region is considered. Two genera and six species including a new species Adiantites tevelevii sp. nov. are described. A new species is determined on the basis of pinna morphology. Detailed features of pinnule venation of studied genera are discussed. Hook-like recurved structures are distinguished on the medullosalean rachides. Paleoecological groups of studied pteridosperms are suggested. [ABSTRACT FROM AUTHOR]