THE ANCIENT FERNS 



of larger and smaller ones is shown, natural size, in Fig. 264, and the larger ones can be 

 seen to be branched. Some sections through fertile regions are shown in Fig. 266, and the 





*^A ^ 



0. lusifanicum n- c. I 28 



Ophio^lossum \/ulgdtum n = c. dS6 



Fig. 263. Explanatory diagrams to Fig. 262. x 1500. 



soft undifferentiated central tissue can easily be seen. As in Psilotum, the prothallus lives 

 saprophytically with the aid of an endophytic fungus, and in most details my own obser- 

 vations merely confirm the very excellent general description given by Bruchmann in 



265 



