CHARACTERS OF TRIBES AND GENERA. 99 



Obs. — Representatives of tliis 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, but none as yet have been observed 

 in the Western hemisphere. 



15. NlPHIDIUJI, /. Sm. 

 Polypodium sp., cmct ; Rooh. Sp. Fil. 



Surculmn thick Ciiespitose. Fronds stipate, linear lanceo- 

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

 side smooth and g-lossy, 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 genus is a native 

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

 from whom Sir Wni. Hooker received specimens, and 

 I possessed a specinnen of it collected by Hartwog. 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 Ni'plioholus, but from which it differs in 

 having oblique uniserial sori, which also distinguishes it 

 from Niphopsis. 



Sp. N. americana, /. Sm., Hook. 



16. CoLTSis, Presl. (1849.) 



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



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

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



