n r A 



jd4 



MOSSES AND FERNS 



CHAP. 



develop no mesophyll, and die as soon as the spores are 

 scattered. 



T/ie Roots 



The roots of the mature sporophyte differ very markedly 

 from those of the other Leptosporangiatai, and have been the 

 subject of numerous investigations, but there still is a good 

 deal of diversity of opinion as to their exact method of growth. 

 Bower -^ states that in 0. I'egalis there may be a single apical 



Fig. 182. — A, Longitudinal section through the root apex of O. cinnavzoi7iea ; t, young tracheids, 

 X2co; B, cross-section of root apex of 0. Claytoniana, X200. 



cell, such as exists in the first root of 0. Claytoniana and O. 

 cinnamomea, but that it never shows the regular segmentation 

 of the typical leptosporangiate root, and it may be replaced by 

 two or three similar initials. In Todea barbara he found four 

 similar initials, and in no case a single one, although Van 

 Tieghem and Douliot ^ ascribe to this species a single three- 

 sided apical cell.^ 



Osviunda cinnamomea (Fig. 182, A) shows a single very 



^ Bower (11), pp. 310, 314. " Van Tieghem and Douliot (5), p. 378. 



^ Lachmann (i) asserts, however, that he found a group of initials such as Bower 

 describes. 



