CYCADALES 



lOI 



ovules get large, some of the hairs are lost, and the ripe seeds have a 

 soft orange-red color. 



In the various species of Cycas there can be traced a gradual re- 

 duction in the size of the sporophyll, a reduction of the leaflets until 

 the sporophyll has merely a serrate margin, and a reduction in the 

 number of ovules to a single pair, the number characteristic of all 

 the other genera (figs. 96 and 97). 



Fig. 93. — Dioon edule: two male plants at the left and a female plant at the right. 

 Chavarrillo, Mexico (September, 1906). The taller plants, to the top of the leaves, are 

 about 7 feet high. — From Chamberlain, Elements of Plant Science"^ (McGraw-Hill 

 Book Co.). 



In Dioon edule the sporophylls have lost even the serration, but 

 are broad and loosely compacted into a cone (fig. 98). The final 

 stage, with much reduced sporophylls and very compact cone, is well 

 illustrated by Zamia (fig. 99). 



The various genera show various reductions from the leafy char- 

 acter to a peltate sporophyll bearing scarcely any resemblance to a 

 leaf (fig. 100). In Macrozamia the rachis of the sporophyll remains 

 as a more or less prolonged, tapering spine, especially in the upper 

 part of the cone. In Ceratozamia and Encephalarlos the terminal 



