202 



MOSSES AND FERNS 



CHAP. 



very much thickened, and upon the apophysis are found 

 stomata quite similar to those found upon the sporogonium 

 of Anthoceros or the leaves of vascular plants. Haberlandt ^ 

 showed that while the form of the fully -developed stoma 

 in Funaria differs from that of most vascular plants, this 

 difference is secondary, and that in its earlier stages no 

 difference exists. This can be easily verified, and with little 

 difficulty all the different stages found. The young stoma 



B. 



1- 



0. 



Fig. gg. — A, Longitudinal sections of a nearly ripe capsule of F. Jiygrojnetrica, X 260 ; per, peristome ; 

 r, annulus ; t, thickened cells forming the margin of the theca ; B, the sporogenous cells shortly 

 before the final divisions ; i, inner ; o, outer spore-sac, X 525. 



(Fig. 1 01) has the division wall extending its whole length, 

 as is the case in stomata of the ordinary form. As the stoma 

 grows larger, however, the median wall does not grow as fast 

 as the lateral walls, and a space is left between its extremities, 

 so that the two guard cells have their cavities thrown into 

 communication, and the division wall forms a cellulose plate 

 extending from the lower to the upper surface of the stoma, 

 but with its ends quite free. The formation of the pore by 

 the splitting of the middle lamella of the division wall takes 



^ Haberlandt (4), p. 464. 



