Pteridospermales

Abstract

The discovery of this group of gymnosperms from the Palaeozoic is one of the notable achievements of the palaeobotanists, and of enormous importance to phylogeny. It includes fern-like assemblage of seed plants which first appeared in the Upper Devonian. It extended to the Mesozoic through the Carboniferous and Permian (Fig. 1.1) and became extinct millions of years ago. Originally, they were presumed to be ferns and the name age of ferns given to the Carboniferous period was largely due to this misconception. Williamson (1887) first recognized, in the carboniferous flora, plants combining in their anatomical structures the characters of both ferns and cycads. Keeping this in view, H. Potónié (1899) named this group Cycadofilices to indicate its composite character. It was later discovered that most of these fern-like leaves were associated with true seed structures. Because of their similarities to the pteridophytes on the one hand, and spermatophytes on the other, the name Pteridospermae was proposed by Oliver and Scott (1904). It also included Cycadofilices (plants containing seeds).