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A TEXT-BOOK OF BOTANY 



dophytes and Spermatophytes have vascular systems, but 

 only the latter produce seeds. 



122. General characters of Gymnosperms. The Gymno- 

 sperms are one of the two groups of seed-plants, the most 

 familiar ones in temperate regions being pines, spruces, 

 hemlocks, cedars, etc., the group commonly called ever- 

 greens. It is an ancient group, for its representatives were 

 associated with the giant club-mosses and horsetails in 

 the forest vegetation of the Coal-measures. Only about 

 four hundred species exist to-day as a remnant of its former 

 display, although it still forms extensive forests. Gymno- 

 sperms are very diverse in habit. They are all woody 

 forms, but they may be gigantic trees, trailing or straggling 

 shrubs, or high-climbing vines. There are two prominent 

 living groups of Gymnosperms. 



FIG. 200. A cycad with tuberous or short thick stem. 



Cycads are tropical forms with large fern-like leaves. 

 The stem is either a columnar shaft crowned with a rosette 



