388 



MOSSES AND FERNS 



CHAP. 



any distinct lamina. The fertile leaves are pinnately divided. 

 In other species, e. g., S. dichotoma, the leaves are dichoto- 

 mously divided, but the fertile leaf-segments are pinnate, as they 

 are in 6^. pusilla (Diels ( i ) ). 



In Anehnia (Fig. 225) the two lower pinncX of the sporo- 

 phyll are fertile, and in most species become very Ic^ng-stalked 

 and more divided than the sterile pinnae. The leaves arise from 

 the dorsal side of the rhizome and in Lygodiuin, Prantl (5) 

 states that they form but a single row. He also says that the 



Fig. 226. — A, Apex of a young, fertile leaf-segment of Ancimia Phyllitides, X200; 



B, transverse section of young fertile leaf-segment of Scliicaca Pcnnula, Xioo; 



C, part of a similar section oi a somewhat older leaf, Xioo; sp., young sporangia; 

 in, indusium. (All figures after ..^rantl.) 



roots are always diarch, like the Polypodiace^e, but gives no 

 further details of their growth or structure. 



The Sporangimn 



The development of the sporangia has been carefully in- 

 vestigated by Prantl (5) and in origin and arrangement they 

 differ decidedly from the other Le|)tosporangiates, Imt approach 

 most nearly Osinnnda, and among the eusporangiate Ferns 



