2 BOTANICAL GAZETTE [JANUARY 
distribution, the altitude of which was not determined. Most 
of my material came from this region, largely from the hacienda of ~ 
Sefior Luis CARAZA. 
It is a pleasure to acknowledge my indebtedness to Governor 
Treoporo A. Drenesa and Mr. ALEXANDER M. Gaw. During my 
first trip to Mexico in 1904, I failed to find any Ceratozamia, except — 
a few seedlings at Chavarrillo, but after I had returned to Chicago, — 
Governor Deuesa stationed an officer near cultivated plants in the : 
park at Jalapa, and the officer questioned country people until he — 
found one who knew where the plant grew wild. The region was — 
the mountainous slope of the valley just referred to. After that, 
cones were easily secured, and for six years Mr. Gaw has sent cones — 
at all seasons, until the seriesis very complete. Besides, I have been 
able to visit the valley myself, first in September 1906, and later 
in March 1908. On the latter trip, and again in September 1910, 
I found Ceratozamia in the mountains across the Papaloapan River 
at Tuxtepec, but the plants were rather small and bore no cones. 
The plants in the valley, near Jalapa, I identified as Cerato- — 
zamia mexicana. There is considerable variation, aside from that 
which the leaves of cycads present at various stages in the growth 
of the plant, the variation appearing even in the cones, which show 
less variation than the vegetative structures. 
In habitat Ceratozamia differs decidedly from Dioon edule, 
which grows in the open, exposed to blazing sunlight, while Cerato- 
zamia is found in densely shaded places. The difference in light 
will be appreciated from the fact that a photographic plate which 
would be well exposed for Dioon in one-fifth of a second would 
require three minutes exposure for Ceratozamia. The Ceratozamia— 
associated with Dioon at Chavarrillo always appeared stunted, with 
one, two, or three leaves, except on Monte Oscuro, where it is” 
shaded by a dense growth of shrubs. Although Ceratozamia is” 
not found in wet situations, it is associated with a luxuriant vegeta- _ 
tion, while Dioon edule and the plants associated with it are xero- _ 
phytic. The habitat of Ceratozamia resembles that of Dioon 
spinulosum, but the latter plant does not occur in the Jalapa region. — 
In the Tuxtepex region Ceratozamia appears before the 
locality is reached, but I did not find the two growing together. 
