

232 BOTANICAL GAZETTE [makh 



regarded as an objection by those who lay great stress upon the 

 importance of a rigid sequence of cell divisions. 



sperms 



from 



formed 



within mother cells or not. Webber 



mother 



become ciliated. Caldwell (9) 



Microcy 



L 6 



noncommittal. Miyake (6) 



make a definite 



body cell i 



Cycas. I have examined Zamia and find that the sperms are organ- 

 ized within definite sperm mother cells, and have found the same 

 situation in Ceratozamia. This condition is probably general in 

 cycads. 



In bryophytes the final division of the spermatogenous cells results 

 in conspicuous pairs of sperm mother cells, or perhaps, as has been 

 claimed, two sperms are formed in a single mother cell. In pterido- 

 phytes the pairs are not so conspicuous, but the feature is just as defi- 

 nitely present. In nearly all gymnosperms the spermatogenous 

 tissue has become reduced to a single pair of spermatogenous cells, 

 which in some cases, as in Juniperus, bear a striking resemblance to 

 the sperm mother cells of cycads. In Juniperus, however, no vestige 



of a blepharoplast has been reported, and it is assumed that the 



In forms like Pinus, there 



is merely a nuclear division within the body cell, giving rise to two 

 sperm nuclei, no sperm mother cells being formed. In Pinus there 

 are structures which may be vestiges of blepharoplasts. It would be 



sperms 



form 



Juniperus or Thuja would show n( 

 blepharoplasts within mother cells. 



of 



sperms 



cycads to identify the genera bv this character alone. A comparative 

 study wffl be made later, but a few features will be mentioned here. 

 In Cycas the spiral makes five and a half to six turns, the direction 

 being from right to left, as viewed from above. In Zamia, accortW* 

 to WeBBER (2), there are five to six turns, always from left to rig • 



