ALLOSORUS. 



55 



GENUS n. 



ALLOSOEUS. Berxhardi. 



This genus is represented in Great Britain by a solitaiy 

 species. 



The fronds are herbaceous, dimorphous, bi-tripinnate, the 

 fertile fronds contracted and erect in habit; the barren fronds 

 much resembling parsley. In general appearance the Allosorus 

 bears some resemblance to the genus Pteris, but the fructification 

 is more nearly allied to Polypodium, the receptacles are puncti- 

 form, and the sori non-indusiate ; eventually confluent. The 

 revolute margin of the pinnules covers the sori. 



Veins simple, or forked from a central costa. 



