210 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. Gymmno- 
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. 
Fic. 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 
