376 



MOSSES AND FERNS 



CHAP. 



The Sexual Organs 



Bower (8) has investigated the structure of the anther- 

 idium in Trichomanes, and Goebel (lo) in both Trichomanes 

 and Hymenophyllum. My own study of their development 

 has been confined to an undetermined species of Hymenophyl- 

 lum from the Hawaiian Islands, but the results of my observa- 

 tions agree entirely with those of other observers. The anther- 

 idia arise mainly upon the margin of the prothallium, or upon 

 the ends of the filamentous ones. After the mother cell is cut 



Fig. 217. — Hymenophyllum (sp). Development of the antheridium, X260. A, D, 

 From living specimens; E, microtome section; B i, C 2, D i, optical sections; 

 B 2, C I, D 2, surface view of the same. 



off, there is usually formed another transverse wall, by which 

 a short pedicel is produced. A funnel-shaped wall does not 

 ever seem to be formed, but the next division walls are more 

 like those in Osmund a, and extend only part way round the 

 circumference of the mother cell. After a varying number of 

 basal cells are thus formed, a dome-shaped wall arises, separat- 

 ing the central cell. This wall is not so convex, as is usually 

 tlie case in the Polypodiace?e, and in this respect, as well as the 

 form of the wall cells, the antheridium resembles that of Gleich- 



