304 



GYMNOSPERMS 



is densely packed with protoplasm, and stains deeply, appearing as 

 in figs. 308 and 309 yl. In fig. 309 B, the megaspore has aborted, and 

 is probably represented by the black streak between the two groups 



of enlarged cells. Whether one 

 or more of these enlarged cells, 

 which, normally, would have 

 been merely nutritive cells, 

 might develop into a functional 

 gametophyte was not deter- 

 mined. It would be worth 

 while for someone, in contact 

 with this western conifer, to 

 work out its entire life-history. 

 The reduction division in mi- 

 crosporogenesis in angiosperms 

 has been studied, described, 

 and philosophized about, until 





Fig. 30Q. — Finns contorla: A, megaspore 

 mother-cell developing normally, with 

 Sfwngy tissue around it; li, in this case, the 

 mother-cell has aborted and the surrounding 

 tissue is developing strongly, looking like a 

 group of mother-cells; Xsoo. 



Fig. 310. — Finns laricio: mega- 

 spore mother-cell as it appears in the 

 Chicago region, about June i. Tiic 

 spongy tissue has the normal appear- 

 ance. — From Coulter and Ch.vm- 

 BKRLAIN, Morphology of Gymno- 

 sperms^^ (University of Chicago 

 Press) . 



