194 BOTANICAL GAZETTE [MARCH 
angial origin of the sorus. In the former, while the sporangia of 
a sorus are usually quite distinct, occasionally they are free for only 
about half their length (jig. 17); while in the latter this half-synangial 
character is more common (jigs. 15-20). 
One cone of Zamia floridana showed great variation in the number 
of sporangia on a sporophyll. The usual sporophyll (fig. 21, a) bore 
twelve on each flank, arranged in six pairs. Usually each flank 
had the same number of pairs, but this was not always the case. The 
number of sporangia ranged from two to forty-eight; and instead of 
being confined to the flanks, in several cases there were groups of 
sporangia on the middle region or even all the way across the sporo- 
phyll, approaching the condition in Ceratozamia (figs. 21, 6, ¢). 
The number was likely to be less upon the sporophylls near the tip 
of the strobilus and upon those at the base. One sporophyll is shown 
in fig. 21, d, which suggests the megasporophyll in the position and 
number of sporangia; and it may be interesting to note that an ovulate 
cone furnished several sporophylls with two sporangia on each flank. 
DEVELOPMENT OF SPORANGIA 
Two papers by WArminc (6, 7) give the earliest information con- 
cerning the development of the microsporangium of cycads, the species 
investigated being Ceratozamia mexicana and Cycas circinalis. 
Later, TREUB (8) investigated Zamia -muricata and LANG (16) 
Stangeria paradoxa, both giving an account of the sporangium from 
its. early stages to its maturity, but neither obtained stages earlier 
than a several-celled sporogenous tissue. 
A tangential section through the strobilus of Zamia floridana gives. 
the best view of the origin of the sporangia (fig. 14); about three 
showing upon each lobe of the sporophyll in such a section, the 
youngest near the margin. The cells in the region where the spo- 
rangia arise stain more deeply than the rest of the tissue, and this mer- 
istematic condition extends below the sporangia for some distance. 
The epidermis here divides only anticlinally. In such a section as. 
fig. 14, certain cells may be distinguished by their larger size, more 
deeply staining contents, and larger nuclei in which the chromatin. 
is more prominent. This is the region which will give rise to the 
sporangia. In such meristematic groups a single hypodermal cell 
with large nucleus and deeply staining chromatin can be distinguished, 
4 
‘eae 
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