22 



MOSSES AND FERNS 



CHAP. 



dichotomous, and as this is rapidly repeated, it often causes the 

 thallus to assume an orbicular outline. Some forms, however, 



B 



S P-. 



FIG. I. Marchantiales. A, B, Male plants of Fimbriaria Calif ornica. A, from above; 

 B, from below; g, antheridial receptacle; /, ventral lamellae, X4; C, Riccia glauca, 

 X6; sp, sporogonia; D, Conocephalus conicus, X4J E, Targionia hypophylla, X2; 

 ($, antheridial branch. 



e.g., Targionia (Fig. i, E), may fork comparatively seldom, 

 and the new branches are for the most part lateral. The thallus 



