THE STORY TOLD BY FOSSIL PLANTS 



called the age of 

 gymnosperms 

 (plants with naked 

 seeds, such as the 

 pines), but it may 

 perhaps be more 

 properly called the 

 age of cycads (Figs. 

 8 and 9), for its 

 rocks contain cycad- 

 like plants in great 

 abundance and 

 variety. 



The known Juras- 

 sic floras, whether 

 of swamp or upland, 

 consisted primarily 

 of ferns, cycads, and 

 conifers. The ferns 

 were all forms of 

 moderate size. 

 None of the cycad- 

 like forms that are 

 so characteristic of 

 that age of the 

 earth's history were 

 tall; probably none 

 were as tall as an 

 old cycad of to-day. 

 Rising above the 

 general low level of 

 these cycads were 

 the various conifers, 



Fig. 5. — Restoration of Protolepidoden- 

 dron, an upper Devonian ancestor of the 

 subsequently differentiated forms of Lepi- 

 dodendron and Sigillaria, the arborescent 

 Palaeozoic club mosses. (After Berry.) 



a, Lepidodendron-Iike leaf sears; b, Sigillaria- 

 like leaf sears; c, leaf, about natural size. 



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