SPERMATOPHYTES 



Ovulate. The 

 ovulate strobili (fig. 

 442) are sometimes 

 very large. The 

 genus Cycas is 

 peculiar in its ovu- 

 late strobilus, in 

 that it is not a com- 

 pact strobilus, but 

 a rosette of spo- 

 rophylls resembling 

 reduced foliage 

 leaves, in which 

 ovules replace the 

 lower piimae or 

 teeth (figs. 443, 444). 

 In general, the spo- 

 rophylls vary from 

 the leaflike (pin- 

 nate) forms of Cycas 

 to peltate forms (as 

 in Zamia, fig. 441, 

 and Ceratozamid, 

 fig. 445). Between 

 these extreme forms 

 there is a complete 

 series of transitions, 

 but there is always 

 a terminal sterile region of varying form, 

 from five or six to two. 





FIG. 439. Staminate strobili of Dioon. After 

 CHAMBERLAIN. 



The ovules vary in number 



440 



FIGS. 440, 441. Stamens (microsporophylls) of Cycas circinalis (440) and Zamia 

 integrifolia (441). After RICHARD. 



