REPRODUCTIVE ORGANS 



457 



FlG. 122. A, male cone of Zamia, showing the hexagonal sporo- 

 phylls (sp. ph. <J ). 



B, transverse section of the same, showing the microsporangia (;;//. 

 spg) borne on the sporophylls. 



c, distal end of female cone of Zauna, showing the sporophylls (sp. 

 ph. 9 ). 



D, transverse section of the same, showing the megasporangia (mg. 

 spg) borne on the sporophylls. 



E, a single female sporophyll (sp. ph. 9 ) of Cycas, the pointed lobes 

 of the distal portion replaced proximally by megasporangia (mg. spg). 



(After Sachs.) 



integument is in close contact with the nucellus, but is per- 

 forated distally by an aperture, the micropyle (mpy\ through 

 which a small area of the nucellus is exposed. 



Each megasporangium contains only a single megaspore, 



