81 



Indusium quite continuous, sori linear, conti- 

 nuous, occupying a slender filiform receptacle in 

 the axis of the indusium. Veins free, rarely 

 those of the last division but one or more are 

 less connected by arching veins at the very 

 base. 



I. Stipes tufted, indusium single. 



(a) Integrifoliae. Lower pinnae linear, un- 

 divided. 



i. P. longifolia. 



(b) Furcatae. Lower pinnae forked or 

 slightly pinnate. 



(*) Pinnae of the sterile frond consider- 

 ably broader than the fertile and 

 distinctly toothed. 



1. Sterile frond about the size of the 



fertile. Lower pinnae cleft down 

 into two or three pinnules. 



2. P. cretica. 



2. Sterile frond much smaller than 



the fertile and more compound. 

 Lower pinnae simple, forked, trifid 

 or compound. 



3. P. ensiformis. 



