REl'RODUCTIVE ORGANS 



457 



sp.ph.S 



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

 phylis (sp. ph. S). 



B, transverse section of the same, showing the microsporangia (mi. 

 spg) borne on the sporophylls. 



c, distal end of female cone of Zamia, 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 pro.ximally by megasporangia {nig. spg). 



(After Sachs.) 



integument is in close contact with the nucellus, but is i)er- 

 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, 



