396 
STRUCTURE AND LIFE HISTORIES 
nately divided blade, with mid-rib and petiole (Fig. 292). 
The genera that bear the megasporophylls on the main 
stem resemble the ferns, and in this respect are the simplest, 
or most primitively organized, of all living seed-plants. 
354. Megasporangia. Unlike the microsporangia, the 
megasporangia of Cycas occur, not in groups, but solitary 
FIG. 292. Young megasporophyll (carpel) of Cycas revoluta, bearing 
six young ovules, destined, after fertilization, to mature into seeds. Note 
the relatively large amount of leaf-blade above the ovules, as compared 
with Cycas media (Fig. 293). (Specimen from C. C. Chamberlain.) 
on the lower part of the sporophyll, at the margin, occupy- 
ing the position of the pinnate divisions (Figs. 292-294). 
In genera bearing carpellate cones the megasporangia 
occur in pairs on the under surface of each scale (mega- 
