CYCADALES 



147 



tube; but in Microcycas Caldwell (52) describes and ligures sixteen 

 to twenty sperms (figs. 174, 175), and four sperms are found occa- 

 sionally in Ceratozamia (53). It is evident that in Microcycas the 

 body cell has given rise to eight or ten spermatogenous cells, each 

 of which has produced two sperms. Cupressus Goveniana, described 



175 



Figs. 174, 175. — Microcycas calocoma: lig. 174, pollen tube showing nine sperma- 

 togenous cells, in most of which the blepharoplasts are seen; X160; %. 175, later 

 stage showing sections of 15 sperms; X450. — After Caldwell (52). 



by JuEL (39), has four to twenty sperms, all derived from the body 

 cell. The large number of sperms is doubtless a primitive character, 

 as both investigators suggest, but the cases seem somewhat different, 

 since in Microcycas the condition may have persisted from earlier 

 forms, while in Cupressus Goveniana it is more likely to be a reversion. 

 The sperms of cycads are remarkably large, in fact larger than any 



