22 



CYCADALES 



[CH. 



goose's egg: the sterile distal end has the form of a spear-point 

 with an irregularly serrate edge. In C. revoluta, C. pectinata, etc., 

 the sterile part is deeply dissected and may break off (fig. 392, A) 

 from the fertile portion of the sporophyll. The megasporophylls 



Fia. 393. A. Stangeria paradoxa, part of microstrobilus. 



B, D. Encephalartos villosus, megastrobilus in surface-view and in 



section. (\ nat. size.) 



C. Ceratozamia mexicana, single megasporophyll. 



of C. Riuminiana exhibit a striking variation in form (fit?. .392, B, 

 C) ; some are 15 cm. long with several ovules, while others^ 

 reduced to 8 cm., bear only two ovules and resemble the sporo- 

 phylls of Dioon. In all other genera the megasporophylls are 



