SPERMATOGENESIS IN DIOON EDULE 1 



CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 125 



Charles J. Chamberlain 



* 



(with plates xv-xviii and three figures) 



In March, 1904, and again in September, 1906, the writer visited 

 Mexico for the purpose of studying the Mexican cycads and collecting 

 material for morphological work. The field study was greatly facili- 

 tated by the active cooperation of Governor Teodoro A. Dehesa, 

 whose active interest in education has done so much to raise the 

 educational standard of the State of Vera Cruz. I am also deeply 

 indebted to Mr. Alexander M. Gaw, of the State Bureau of Infor- 

 mation, Xalapa, Mexico. Mr. Gaw not only supervised the col- 

 lection of material and forwarded it to me, but on several occasions 

 visited localities where D loon edule grows and sent me valuable field 

 notes with the collections. The material was collected at Chavar- 

 rillo, Mexico, the locality which furnished material for my account 

 of the ovule and female gametophyte of Dioon edule. 



THE STAMINATE CONE 



In March 



ovulate 



September have reached their mature size, but the stamina 

 from which they were pollinated have disintegrated. Both th< 

 a nd the staminate cones which are to appear a few months later are 

 ^ hidden in buds which cannot be distinguished from leaf buds. 



Until they reach a length of about io cm the staminate cones are 

 completely hidden by large bud scales which are fleshy and very 

 ■*& so that the whole structure looks like a moderate-sized ovulate 

 C0Q e. The surface of the cone at this time is densely covered with 

 w Wtish hairs, which become darker when the cone emerges from the 



Protecting 



In Se Ptember the staminate 



pollen. 



firm 



Ame 



"31 



[Botanical Gazette, vol. 47 



