364 



MOSSES AND FERNS 



CHAP- 



cell. This wall is not so convex, as is usually the case in the 

 Polypodiaceae, and in this respect, as well as the form of the 

 wall cells, the antheridium resembles that of GleicJienia. In 

 the Hymenophyllaceae no cap cell is formed, but as in Osmunda 

 and GleicJienia, the upper cell is divided by walls running over 

 the apex. The divisions in the central cell and the structure 

 of the spermatozoids, so far as these have been studied, 

 correspond with those of the other Leptosporangiatae. 



A single archegonial cushion is not formed, but the 

 archegonia occur in small groups at different points upon the 



Fig. \ZQ.—Hymenophylluin (sp). Development of the antheridium, X260. A, D, From Hving 

 specimens; E, microtome section; B i, C 2, D i, optical sections; B 2, C i, D 2, surface view 

 of the same. 



margin. Goebel ^ has shown, however, that these archegonial 

 groups arise first near the growing point of the prothallial branch, 

 and that they are simply separated by the intervention of zones 

 of sterile tissue. At the point where they arise the prothallium 

 becomes more than one cell thick, and in all cases where the 

 development could be certainly followed, the archegonium 

 arose from one of the ventral cells, and never directly from a 

 marginal cell. The details of the development have not been 



^ Goebel, Ueber epiphytische Fame und Muscineen. Ann. dn Jardin botanique 

 de Bicitenzorg, vol. vii. p. 105. 



