68 EVOLUTION IN THE PAST 



march on other club-mosses by producing seeds instead of 

 spores had resulted in complete failure ; and no ambitious 

 speculations in reproduction were again attempted. 



Several new genera of ferns were superseding those of 

 earher times. In the southern hemisphere and also in 

 northern Russia some hardy species with simple leaves 

 variously shaped became abundant {Glossopteris). In northern 

 Russia certain ferns by stem and leaf-stalk modifications 

 exhibited important advances in development, indicating a 

 greater division of labour {Zalesskya, Thamnopteris). Cycad- 

 fems continued numerous, but were now yielding to forms 

 not far short of being true cycads (Pterophyllum, Sphenoza- 

 mites). Meanwhile the old flower-bearing cordaites were fast 

 succumbing. 

 CONIFERS The most notable Permian growths were of true conifer 

 character. Primitive conifers — derived from plants of the 

 Cordaite type (Cordaitales) — were probably, at least in sparse 

 numbers, in Carboniferous woodlands ; but the stability of 

 the line was not weU estabhshed until late in the Permian 

 Period. Many weU-developed forms then adorned the land- 

 scapes : and although they differed in some respects from 

 living conifers, they can be brought more or less into line 

 with them. Some were closely allied to cypresses and 

 araucarias (Walchia, UUmania) ; some to spruces and 

 Sequoia firs (Voltzia, Schizolepis) ; and some to yew, and 

 gingko or maidenhair trees (Baiera, G. primigenia). These 

 various growths, however, brought no bright colours in their 

 train ; and vegetation remained of a dull, monotonous hue. 

 Nor were there as yet any birds, or even butterflies, to reheve 

 the sombrous scenes. 



This brings us to the close of what is known as the Palseozoic 

 Age. This Age with its six Periods must have lasted many 

 miUions of years ; and was probably more than thrice as 

 long as aU the time that has elapsed since its close. 



Progress, if slow, was sure. Plant-life, consisting in the 

 Cambrian probably of algae, funguses, lichens, liverworts, 

 and other humble spore-producing growths, underwent in 

 time various modifications, resulting in ferns, " horsetails," 

 and club-mosses. Then came seed-bearing cycad-ferns and 



