XV.—On Protopitys (Göppert): with a Description of a Fertile Specimen Protopitys scotica sp. nov. From the Calciferous Sandstone Series of Dunbartonshire.

Abstract

SynopsisA Fertile shoot of Protopitys scotica sp. nov. from the Calciferous Sandstone Series of Dunbartonshire provides the first available information about the reproductive structures of Protopitys which most authors have hitherto regarded as probably a Pteridosperm. The evidence, however, suggests that it is a plant with pteridophytic reproduction. The range in size of the spores suggests too that heterospory with two sizes of spores, megaspores and microspores, was in course of evolution. It is proposed that a new group, the Protopityales, be established to include Protopitys.