230 BOTANICAL GAZETTE [make 



plasm of the body cell, but no convincing early stages are given. 

 Caldwell's (9) material was all too far advanced to show the origin 

 of the blepharoplasts. 



It seems probable that the manner in which the spiral band is 

 formed from the blepharoplast is similar, in its main features, in all 

 the cycads. The solid blepharoplast becomes vacuolated and then 

 breaks up into a group of granules from which the ciliated band is 

 formed. Caldwell (9) describes in Microcycas a band, already dis- 

 tinct during the division of the body cell, and says that this band 

 becomes broken up into fragments upon which the beginnings of 

 cilia may be seen. His fig. 25 indicates that the band is a sec- 

 tion of the rim of the much vacuolated blepharoplast, while the 

 "fragments" in his fig. 27 are sections of the spiral band, which ha 

 already made several turns. The cilia which he figures on the inside 

 of the fragments need confirmation. 



The origin of the blepharoplast in pteridophytes has been con- 

 sidered by several investigators, all of whom agree that it first appears 

 in the cytoplasm. Some find it present even from the early sper- 

 matogenous divisions, while others find it first in the cell which is to 

 give rise to two sperm mother cells, or, occasionally, one generation 

 earlier than this. In a very detailed account of spermatogenesis - 

 Nephrodium, Yamanouchi (ii) finds that two blepharoplasts first 

 appear in the cell which is to give rise to two sperm mother cells. 

 The blepharoplast in pteridophytes simply elongates and forms the 

 band directly, there being no radiations, no vacuolation, nor break- 

 ing-up into a group of granules which subsequently give rise to a spiral 

 band. While the blepharoplasts of ferns and cycads are doubtle. 

 homologous structures, no intermediate conditions have yet been found 

 which would explain the behavior of the blepharoplasts of cycads. 



In Dioon edule, as in nearly all gymnosperms, only two sperms 

 are formed in the pollen tube. In a few instances I have noted four 

 sperms in the pollen tube of Ceratozamia mexicam. Juel (3) iom A 

 four to twenty sperms in the pollen tube of Cupressus Goweniana 



in 



,a 



nd 



naturally regarded the condition as primitive. Caldwell (9) foU ^ f 

 ""[* twenty sperms in Microcycas calocoma, and on the basE ^ 



this character claimed Microcycas to be the most primitive cyca 



sixteen or 



yet described. 



