488 



MOSSES AND FERNS 



CHAP. 



somewhat older stages (Fig. 254, A) the nuclei were more nearly 

 globular in outline, and were more numerous at the apex of 



per. 









B, 



Fig. ^SA-Selaghiella Kraussiana (A. Br.). A, Section of the upper part of a macrospore still within 

 the sporangium, shortly before the first cell-formation, XS25 ; B, a somewhat earlier stage, show- 

 ing the very thin protoplasmic layer lining the wall, with the free nuclei {n), X525 ; C, transverse 

 section through the apex of the macrospore, showing the first cell-formation, X 570. 



the spore, where the protoplasmic layer lining the wall was 

 also noticeably thicker. Shortly after this the first cell division 



