410 BOTANICAL GAZETTE [DECEMBER 
sporophyll of D. spinulosum is thick, fleshy, and rounded or obtuse 
at the apex, contrasting again with the long tapering sporophylls of 
D. edule and D. Purpusii. The contour of the exposed portion of 
the sporophylls and the close imbrication is seen in fig. 4, especially 
near the apex of the cone. 
The seeds are white and perfectly smooth, but may become 
slightly yellowish when mature; their length varies from 4 to 5.5°™ 
and the diameter from 2.5 to 3.5°™. Some of the ovules have the’ 
Fic. 5—Dioon spinulosum; dorsal Fic. 6.—Dioon spinulosum; ovulate 
view of an ordinary sporophyll, the ovule sporophyll, from the cone shown in fig. 4, 
on the left showing the false stalk; from with five ovules, three of which can be seen 
a cone received from Tuxtepec, Apri on the left side, but only a portion of one of 
1907. X#. the two on the right side is visible. X ?. 
false stalk, characteristic of the genus, but it is not as frequent as in 
D. edule (fig. 5). In one cone, with only abortive ovules, there were 
frequently more than two ovules on a sporophyll, in some cases aS 
many as five or six (fig. 6). Cycas, the most ancient genus of the 
family, regularly produces more than two ovules on a sporophyll, 
and in Dioon the production of more than two ovules is doubtless a 
recurrence of the ancient habit. In rare cases, I have noted as many 
as four ovules on the sporophylls of Zamia floridana and Ceratozamia 
mexicana. 
