ONYCHIUM. 61 



GENUS II. 



ONYCHIUM. Kaulfuss. 



The genus Onychium is small, and although Fee in his 

 "Genres de la Famille des Polypodiacees" enumerates the fol- 

 lowing, still only one, namely 0. lucidum, appears to be culti- 

 vated in Great Britain. 



Onychium 



lucidum, 



Hooker. 



tt 



capense, 



Kaulfuss. 



(t 



Japonicum, 



KUNZE. 



a 



auratum, 



Kaulfuss. (Pteris chrysosperma, 

 Hooker.) 



t( 



carvifolium, 



Fee. (Lomaria? Wallich. 



it 



melanolepis, 



Kunze. (Allosorus cuspidatus, 

 Jaubert and Spach.) 



a 



chserophyllum, 



Fee. (Allosorus, Martens and 

 Galleotti.) 



a 



chinense, 



Gaud. 



(t 



robustum, Fee. (Allosurus, Kunze.) 



Fronds deltoid, elongate, acuminate, decompound; veins 

 simple, direct, free on their apices, combined by a transverse 

 sporangiferous receptacle, which is formed in the axis of a 

 linear and slightly intramarginal indusium. Indusium plane, 

 the free margins of each conniving over the midrib, and 

 splitting open along the centre, as. it were by a longitudinal 

 suture. Sori short, linear, continuous, eventually becoming 

 confluent, and covering the whole disc between the two 

 indusia. Rhizoma creeping. 



Formerly Onychium was considered by some authorities a 

 Pteris, and by others a Lomaria, but the distinct habit and 

 dissimilar structure of the fertile fronds have induced botanists 

 to form a genus Onychium. This genus is distinguished from 

 Pteris by the fertile segments being so narrow that the two 



