VOLUME XLII NUMBER 5 
BOTANICAL ©Ga7et ee 
NOVEMBER 1906 
THE OVULE AND FEMALE GAMETOPHYTE OF DIOON. 
CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY. 
LXXXVI. 
CHARLES J. CHAMBERLAIN. 
(WITH NINE FIGURES AND PLATES XIII-XV) 
ONLY two of the nine genera of cycads have received any con- 
siderable attention from morphologists. In these two, Cycas and 
Zamia, the life history is fairly well known and many of its phases 
have been studied in great detail. In Stangeria the development 
of the sporangia has been investigated, and work on the remaining 
six genera is fragmentary. 
Through the courtesy of the Botanical Society of America’ the 
Writer was enabled to visit the Mexican tropics for the purpose of 
securing material of Dioon and Ceratozamia. The hearty coopera- 
tion of Governor Troporo A. Denesa, who is an active educator 
as well as a statesman, made it possible to collect an abundance of 
material in a very short time. Mr. ALEXANDER M. Gaw, of the 
State Bureau of Information, Xalapa, Mexico, had many collections 
of material brought into Xalapa from the field and forwarded to 
me after my return to Chicago. To both of these gentlemen I wish 
to express my sincere thanks, since the investigation would have 
been very limited without their efficient assistance. The photo- 
staphs used were made by Dr. W. J. G. Lanp. 
_The Subject will be treated under the following heads: I. 
Dioon in the field; II. Material and methods; III. The ovule; 
The female gametophyte; V. The microsporangium; VI. 
The grant was made in December 1904 by the Botanical Society, at the St. 
Louis meeting of the A. A. A. S., and was for the purpose of securing material for a 
morphological study of Dioon and Ceratozamia. 
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