﻿1 6 SCOTT, Early History of Seed-bearing Plants. 



It is manifest that the existence of the class Pterido- 

 spermeae in Palaeozoic times has an important bearing 

 on the whole question of the evolution of the Phanero- 

 gamia. On the anatomical evidence alone it has been 

 held for some years by many palaeobotanists that the 

 origin of Cycadaceous Gymnosperms, at any rate, was to 

 be traced to the ferns (Scott, 'oo). Now that we know 

 that the intermediate group on which this conclusion was 

 based, included true seed-bearing plants, with seeds of 

 the same type as those of Cycadaceae, the case is so 

 much strengthened as to be no longer open to dispute. 

 The comparatively slight indications of fern-affinities 

 presented by the recent and the Mesozoic Cycadophyta 

 are accentuated to such a degree among the Palaeozoic 

 Pteridospermeae, as to establish a clear connection with 

 the fern-phylum. 



This is in itself a conclusion of much importance. 

 As all palaeontologists are aware, the Cycadophyta,. 

 though now reduced to a small group, formed, in 

 Mesozoic times, a dominant factor in the vegetation of 

 the world. They were then not only an extensive, but 

 a highly varied class of plants, embracing forms which, in 

 the complexity of their fructification, nearly approached 

 the Angiosperms themselves. In the Palaeozoic rocks 

 the remains referable to true Cycadophyta are scanty and 

 limited to the upper beds, but those of the more primitive 

 class Pteridospermeae are enormously abundant. Thus 



the strong evidence for classing Pecopteris among Marattiaceous ferns. It 

 must be remembered, however, that P. Pluckeneti is one of the Sphenopteroid 

 species, and probably not a typical member of the genus. It was placed in 

 a separate genus, Dicksoniites, by Sterzel, on account of the character of the 

 "sori" (male fructifications?) which, however, are still imperfectly known 

 (Sterzel, '83). 



M. Grand 'Eury is publishing an account of his discovery in the 

 Comptes Rendus of the French Academy of Sciences. 



Note, added April 14th, 1905. 



