446 



SPERMATOPHYTES (SEED PLANTS) 



Cycads 



Of the Gymiiospcrms now in existence, the Cycads bear most 

 resemblance to the Ferns. In leaf and stem characters, some of 

 them could easily be mistaken for Ferns {Fig. 396). There are 

 nearly one hundred species of Cycads. They are tropical plants 

 but are grown nearly everywhere in greenhouses. One of the 



Fig. 396. — A Cycad, showing the finely divided leaves and the short thick 

 trunk with its rough covering of leaf bases. After J. M. Coulter. 



forms (Cycas revoluta) common in cultivation is often labeled 

 " Sago Palm " because its leaves resemble those of some of the 

 Palms. 



Sporophyte. — The sporophyte has a tuberous or columnar 

 stem at the top of which are borne the large, much branched, 

 fern-like leaves. The stems are covered by the leaf-bases which 

 remain after the leaves fall. In some Cycads, where the stem is 

 subterranean, the plant is small, but in others with columnar 

 stems, the plant may reach a height of 50 feet or more. 



Strobili. — The strobili are borne near the apex of the stem of 

 which they are really branches, and are of two kinds — staminate 

 and ovulate. The staminate strobili are simply microstrobili, 

 that is, strobili in which only microsporophylls and microspo- 



