XXIV.—On the Structure and Affinities of Diplolabis römeri (Solms)

Abstract

Probably the commonest type of foliage among the impressions of Carboniferous plants is one which simulates that of our living ferns. These palæozoic fronds were originally believed to belong to the true ferns, but recently some of them have been taken from this group and included in the Pteridospermeæ. There remain, however, a large number of fronds the true affinities of which are yet doubtful. Thus, though there are still a considerable number of species which belong to the ferns, the number of doubtful examples and of those now definitely known to be pteridospermous far exceeds the number of those attributed to the Filices. Indeed, we cannot now consider the latter group to have been dominant during the Carboniferous epoch.