1908] DORETY—CERATOZAMIA 207 
found to have a single cylinder, but peduncular strands occurred in 
the pith, an observation which was corroborated later by WORSDELL 
(16). In the work previously mentioned (6) MatTE made a careful 
study of the ovulate cone and the mature leaf, with a few observations 
on younger leaves. He found terminal teeth on some of the pinnae 
of the younger plants, and at the bases of the petioles stipules with a 
bundle in each. He says that the meriphyte of the leaves has a 
modified Q-shape in cross-section, with an anterior system, and shows 
that in this as well as in other cycad petioles the so-called fusions of 
the traces are often only approximations (accolements). 
| MATERIAL AND METHODS 
The’seedlings of Ceratozamia and Dioon spinulosum were grown 
from seeds provided by Professor CHARLES J. CHAMBERLAIN; the 
Microcycas seedlings were given to me by Professor OTIS W. CaLp- 
WELL, and later some were grown from seeds secured by Professor 
os. The Zamia seedlings were furnished by Dr. W. J. G. 
AND. 
Having in mind the danger of drawing conclusions from a few 
specimens, I have used freely the wealth of material at my disposal. 
The chief part of the investigation was made from material fixed 
Ps picro-acetic-alcohol, stained with safranin and anilin blue, and cut 
in serial sections, Figs. 21, 22, and 23 are diagrams of wax models 
Constructed from serial sections. 
GENERAL DESCRIPTION OF EMBRYO AND SEEDLING 
The seeds of Ceratozamia are about 2.5°™ long and 1.5°™ thick, 
that is, about the same size as those of Dioon edule, and intermediate 
between Dioon spinulosum on the one hand and Zamia on the other. 
Like most cycad seeds, they are flattened on two or three sides by 
the pressure of growth within the cone, and it is not unimportant 
to remember that during the whole period of embryonal development 
~—the longest known for a cycad—the seed lies upon whatever side 
it happens to fall. The single cotyledon begins to be differentiated 
= November, and early in December its appearance is like that 
represented in fig. r. Later it begins to surround the axis (fig. 2); 
4nd finally the two edges meet (fig. 3). In these early stages, the 
coleorhiza is proportionally long; but later elongation of the coty- 
