Ill 



THE JUXCIIRMANNIALES 



87 



the formation of a second apical cell in one of the ycnnij^-est 

 segments. This apical cell is formed by a cnrvcd wall, which 

 strikes the onter wall of the segment (Fig. 37, C). Thus 

 two apical cells arise close together, and as segments are cut 

 off from each, they are forced farther and farther a])art, and 

 serve as the growing point of two shoots, which may continue 



A 



B 



Fig. 39. — Anetira pinnatifida. A, Part of a thallus with two antheridial brancliLS. 

 slightly magnified; B, an archegonial branch, X40; C, cells from the margin of 

 the archegonial branch showing the oil bodies (o), X300. 



to grow equally, when the thallus shows a marked forking 

 {M. furcata), or one of the branches grows more strongly than 

 the other, which is thus forced to one side and appears like a 

 lateral branch (Aneura pinnatifida, Fig. 41, B). 



In certain species of Pallavicinia and Syniphyogyna, and 

 especially in Hyuienophyton (Fig. 38, B), the gametophyte 

 shows a differentiation into a prostrate rhizome-like sterj, 



