SPERMATOPHYTES 
195 
Ovulate. The 
ovulate strobili (fig. 
442) are sometimes 
very large. The 
genus Cycas is 
peculiar in its ovu- 
late strobilus, in 
that it is not a com- 
pact strobilus, but 
a rosette of spo- 
rophylls resembling 
reduced foliage 
leaves, in which 
ovules replace the 
lower pinnae or 
teeth (figs. 443, 444). 
In general, the spo- 
rophylls vary from 
the leaflike (pin- 
nate) forms of Cycas 
to peltate forms (as 
in Zamia, fig. 441, 
and Ceratozamia, 
fig. 445). Between 
these extreme forms 
there is a complete 
series of transitions, 
but there is always 
a terminal sterile region of varying form. The ovules vary in number 
from five or six to two. 
FIG. 439. Staminate strobili of Dioon. After 
CHAMBERLAIN. 
440 
FlGS. 440, 441. Stamens (microsporophylls) of Cycas circinalis (440) and Zamia 
integrifolia (441). After RICHARD. 
