58 J, SMITH ON THE GENERA OF FERNS. 



Ohs. The dense stellated scales or pubescence which ac- 

 companies the soriferous portion (or the whole frond), will 

 distinguish this genus from all other Polypodiece; and which 

 it is the more necessary to observe, because on account of 

 the thick texture of the fronds, the venation is difficult to 

 be seen. In one species (N. sphcerocephalus^) the sori are 

 large, of an oval form, and arranged in one transverse row, 

 which structure might induce us to consider that species as 

 belonging to the subsequent genus Drynaria; but, after a 

 careful examination of its venation, I am induced to retain it 

 here. 



19. Cyrtophlebium, R. Br. 

 (Polypodii sp. Auth. Campyloneurum. Presl.) 



Veins forked or costseform and pinnate, the lower exterior 

 venule {of each fascicle) free and fertile, the others arcuately 

 or angularly anastomosing, producing on their exterior side 

 two or more excurrent, free, fertile veinlets. Sporangia late- 

 ral, or sometimes terminal. Sori round, naked, arranged in 

 two rows, between, and parallel with, the costaeform veins, or 

 irregular. Fronds simple, pinnatifid or pinnate, smooth, the 

 excurrent veinlets sometimes anastomosing with the next superior 

 venule, forming two rows of areoles between each two primary 

 veins, fertile veinlets sometimes very short. 



Examp. 1. C. repens;(Sw.) 2. C. Phyllitidis ; {Linn.) 

 3. C. nitidum; (A:aM^.) 4. C. decurrens ; {Radd.)—IUust. 

 . Hook. Gen.fl. ined. 



Obs. The smooth fronds and distinct sori readily distin- 

 guish this genus from the preceding. In habit, the species 

 agree with a group belonging to the subsequent genus Dry- 

 naria, but which is characterized by a more complex anas- 

 tomosing of the veins. 



20. Phlebodium, R. Br. J. Sm. 



(Polypodii sp. Auth. Pleopeltidias sp. Humb. Hook. Ple- 



opeltis. Presl. Synammiae sp. Presl.) 



Veins pinnate or variously branched ; the venules arcuately 



or angularly anastomosing, producing on their exterior side 



or angular meetings, two (rarely more) conniving or trans- 



