114 GYMNOSPERMS 



lo to 28 mm. in length and 7 to 19 mm. in width; in Ccraiozamia 

 mcxicana, from 10 to 15 mm. in length and 7 to 8 mm. in width; in 

 Zamia Jloridana, about 6 mm. long and 5 mm. wide; and in Zaiyiia 

 pygmaca, about 4 mm. long and 3 mm. wide. 



Fic. 108. — Rncephalartos villosiis: top of male cone, with sporophylls at the top 

 spreading apart and exposing tlie sporangia. The University of Chicago greenhouse. — 

 From a photograph by Si;dc.\vick. 



The micros porangia. — ITie sporangia, always on the abaxial sur- 

 face of the sporophyll, are arranged radially in sori, the number vary- 

 ing from 5 in the Cycas region of the family down to 2 or 3, with oc- 

 casional single sporangia in the Zamia end of the family (figs. 109, 

 no). 



