1909] CHAMBERLAIN—DIOON SPINULOSUM 407 
to that of Encephalartos. The leaves of seedlings have comparatively 
few leaflets, the first leaf sometimes having less than a dozen on each 
side. It is interesting to note that in seedlings the leaves have no 
reduced leaflets, even the lowest being as perfectly formed as those 
in the middle of the leaf. The leaflets of seedlings have fewer spines 
than those of older plants, there being only 2-6 on each margin. The 
midrib is not so large as in D. edule and the leaves are much thinner. 
A few leaflets of a leaf of medium size are shown in fig. 2. 
Remembering that the natives had reported cones growing below 
the crowns, one would naturally think of the condition in Bennettitales. 
Fic. 2.—Portion of leaf of Dioon spinulosum from a specimen at Tlacotalpam; 
X4; the cone shown in fig. 4 came from the same plant. 
A glance at jig. 3 will show that the cone does hang down below the 
crown. An examination of the apex of the stem shows, however, 
that the cone is borne in the center of the crown as in D. edule, but 
that a considerable elongation of the peduncle, together with the great 
weight of the cone, causes the cone to bend over, slip between the 
leaves, and thus hang below the crown. Consequently no seeds are 
found in the nest of the crown as is so commonly the case in D. edule, 
where the germination of seeds in this position often gives rise to 
the appearance of branching. In D. spinulosum branching is rare. 
Seedlings are found for a considerable distance around the large 
ovulate plants. The natives say that at maturity the cone bursts 
with a loud noise, scattering the seeds, or coyoles, the plant being 
called coyolillo. 
