Ancient Plants / Being a Simple Account of the past Vegetation of the Earth and of the Recent Important Discoveries Made in This Realm of Nature

by Marie Carmichael Stopes

That the Pteridosperms in themselves combined many of the most important features of both Ferns and Gymnosperms is illustrated in the account of them given above, which may be summarized as follows:—

Salient Characters of the Pteridosperms
G=Gymnospermic F=Fernlike

F Primary structure of root.

G Secondary thickening of root.

F In Heterangium and Medullosa the

F solid centripetal primary wood of stele.

G Pits on tracheæ of primary wood.

G Secondary thickening of stem.

G Double leaf trace.

F Fernlike stele in petiole.