CHARACTERS OF TRIBES AND GENERA. 99 



OBS. Representatives of this genus are widely spread 

 over the Eastern hemisphere, extending from New Zealand 

 and Australia to the Polynesian and Malayan islands, Japan, 

 India and South Africa, bat none as yet have been observed 

 in the Western hemisphere. 



15. NIPHIDIUM, /. Sm. 

 Polypodium sp., auct ; Hook. Sp. Fit. 



Surculum thick cgespitose. Fronds stipate, linear lanceo- 

 late 1J to 2 ft. long, attenuated, firm coriaceous, the upper 

 side smooth and glossy, the under side densely stellato- 

 tomentose. Primary veins straight oblique. Receptacles 

 compital, forming a row (of about four) of large oval sori, 

 between each pair of primary veins. 



Type. Polpodium americanum, Hook. 



OBS. The only representative of this genns is a native 

 of Ecuador and Quito, observed by Dr. Jameson and Spruce, 

 from whom Sir Wm. Hooker received specimens, and 

 I possessed a specimen of it collected by Hartweg. In 

 general appearance it resembles narrow fronds of Pleuri- 

 dium crassifolium, with which it also agrees in the sori 

 being large and in an oblique row between the primary 

 veins, but differs in the under side being densely stellated 

 tomentose, as in Nipliobolus, but from which it differs in 

 having oblique uniserial sori, which also distinguishes it 

 from Niphopsis. 



Sp. N. americana, /. Sm., Houlc. 



16. COLYSIS, Presl. (1849.) 



Polypodium sp. Gymnogramma sp. auct. and Hook. Sp. Fil. 

 Surculum short, sub-hypogeous. Fronds simple, lobed or 

 pinnatifid, generally membraneous, flaccid, 1 to 3 feet long. 



