238 



SYSTEMATIC BOTANY. 



of the Silurian continued into this age, but they were 

 accompanied with a multitude of vascular cryptogams, 

 and even some Phsenogaras ( Gymnosperms). - For the 

 first time there was a true forest vegetation ; and the 

 great size and number of the plants thus early fore- 

 shadowed the remarkable development which took place in 

 the next age. The groups then existing were as follows : 

 I. The Equisetinise were represented by 

 Calamiies and Asterophyllites (Fig. 343). The 

 Calamites had long, slender, tapering, and 

 jointed stems, sometimes two feet in diameter, 

 and thirty feet high. The sur- 

 face was finely striated, or fluted, 

 and at all the joints were situated 

 whorls of scale-like or thread-like 

 leaves. They were, except as re- 

 gards size, like our living Equi- 

 seta, which grow generally less 

 than three feet high and no 

 thicker than the finger. The 

 Asterophyllites were herbaceous, flexible species, with leaves 

 arranged in whorls at the joints, as the name indicates. 



2. The Ferns were represented by such genera as 

 Cyclopieris and Newopteris. In these the leaflets or pinnae 

 have no midrib. 



3. The Lycopods were Psilophyton, already introduced 

 in the Upper Silurian, Lepidodendron and Sigillaria. The 

 Lepidodendra were gigantic plants, the surface of whose 

 trunks and branches were regularly marked in rhomboidal 

 patterns, or quincuncially, representing the leaf arrange- 

 ment (Fig. 345) ; the branches were clothed with squamous, 



Fig. 343. Asterophyllites latifoliaiTy^wom^in Ag&), 



