liviii. GENERA OP PEEKS : 



POLYPODIES. 



(a) Margins of the fronds revolute, indusioid, i.e., the sori 

 sp uriously-indusia te. 



96. ALLOSORUS, Bernhardi, ScTvrad. neues Journ. Bot. 

 i. pt. 2, 5, 36, t. 2, f. 6. 



Sori spuriously-indusiate, rotundate, covered by the revolute 

 sub-herbaceous margin of the pinnules, at length confluent into 

 a transverse line (parallel to the margin), often becoming effuse ; 

 the receptacles punctiform. Veins in the fertile fronds simple or 

 forked, from a central costa ; in the more divided sterile fronds 

 simple or forked in the ultimate segments ; venules free. 



Fronds dimorphous, dwarf, herbaceous, bi-tri-pinnate ; the fer- 

 tile contracted, i.e., with revolute siliculiform pinnules. Rhizome 

 short, decumbent. The only material difference between this 

 genus, as represented by the common species, A. erispus, and 

 Crypto gramma with which it was doubtfully associated by the 

 author of the latter genus, consists in its having constantly 

 punctiform instead of linear oblique receptacles. In habit and 

 aspect they are the same dwarf, elegant, much divided, with 

 dissimilar fertile fronds. Nevertheless, attaching, as we do, 

 considerable importance to the nature of the receptacle, we 

 venture to regard them as distinct. 

 Ex. : A. crispus, Sernh. I A. SteUeri, Kupr. 



? A. gracilis, Pretl. \ ? A. robustus, Eze. 



97. STRUTHIOPTERIS, Willdenow, Mag. Nat. Ber. 

 1809, 160 ; Sp. PL v. 288. 



ONOCLBA, Sernhardi, and Auct. ; OSMFNDJE sp., Linnceut. 



Sori spuriously-indusiate, rotundate, approximate, at length 

 becoming sub-confluent, covered by the revoluto-convolute atten- 

 uated (membranaceo-scariose) margin of the frond, which simu- 



