322 BOTANICAL GAZETTE [NOVEMBER 
Male gametophyte; VII. Fertilization; VIII. The embryo and 
seedling. The first four are presented in the present paper; the 
remaining subjects have been investigated and the results will be 
published soon. 
I. DIOON IN THE FIELD. 
Dioon edule occurs in great abundance at Chavarrillo, about 25*" 
east of Xalapa, the capital of the State of Vera Cruz. During March 
1904 I made frequent trips through this region and, besides the 
tedious work of preparing material, was able to make a few observa- 
tions upon the plant as it occurs in the field. A second trip, devoted 
largely to field study of both Dioon and Ceratozamia, was made in 
September 1906. As the results of this trip will be published in a 
separate paper, only a brief description of the general appearance of 
Dioon is given at this time. 
Associated with Dioon are occasional specimens of a large Opuntia. 
Orchids and Tillandsias are not infrequent on the trees at the bottom 
of ravines, though neither of these plants flourish on the rocky slope 
where Dioon is at its best. In the lower portions of ravines several 
species of Selaginella are abundant. Dioon is so abundant on the 
rocky slopes that from a favorable point of view as many as a hundred 
plants may be counted. Seedlings are numerous and one always 
meets these and then small crowns before coming upon plants large 
enough to bear cones. In spite of the seedlings, it is doubtful whether 
the limited range is being extended. 
In habit Dioon resembles Cycas revoluta (fig. 1). Some call it 
the “Dolores palm;” but the natives are more likely to call it Tio 
Tamal (“Uncle Tamal”), because they use the large endosperm 
in making tamales. The largest plant measured had a trunk 
nearly 3™ in height, and plants 1-1.5™ in height are not infrequent. 
The trunk often rises obliquely, as shown in the figure, and as noted 
in taxonomic descriptions. 
The age of individuals —Even in the largest plants the leaf scars 
are perfectly distinct over the entire surface, so that it is possible to 
determine with almost absolute accuracy the total number of leaves 
which a plant has borne. Professor Luis Murrtto has estimated 
the age of individual plants by noting the number of leaves in a crown, 
the duration of the crowns (two years), and the entire number of 
