52 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



EXPLANATION OF PLATE IV. 



Nitophyllum harveyanum. 



Fig. 13. Slender form, tetrasporic, showing habit. One-half natural size. 

 Fig. 14. Robust form, showing linear sori and flabellalely expanded habit. 

 One-half natural size. 



Nitophyllum ruprechtianum. 



Fig. 15. Prostrate frond of the stout membranous type. One-half natural 

 size. 



Nitophyllum fryeanum. 



Fig. 16. Prostrate frond of the delicate membranous type, showing rhizoids 

 as minute processes on surface. One-half natural size. 



Nitophyllum andersonianum. 



Fig. 17. Prostrate frond, of the freely branching type, with portions of the 

 bases of erect fronds. One-half natural size. 



