CHARACTERS OF TRIBES AND GENEEA. 175 



anastomose, but agrees in the sporangia being seated in a 

 marginal groove. The upper of these is the largest, repre- 

 senting an indusium analogous to that of I/indscea, with 

 which it is associated in the " Species Filicum," but its 

 very different habit prevents its being associated with 

 Lindscea. It is otherwise peculiar in being the only Fern 

 in Desmobrya having transverse marginal sori, and com- 

 pound anastomosing venation. 



Sp. D. panamense, Hook (v v.)., Hook. Fit. Exot., t. 54. 



Tribe 11. PLEUROGRAMME^E (Plate 11). 



Fronds simple, 1 to 10 and 12 inches in length, entire, 

 serrate, rarely dentate or laciniated. Sori linear, transverse 

 costal, or oblong sub-linear, oblique. 



OBS. This tribe contains about thirty small, and with 

 the exception of a few, grass-like Ferns, and although the 

 character of the sori does not technically differ from 

 Gymnogramme, they nevertheless are so different in habit 

 that they do not form a natural connection with that 

 genus ; I therefore deem it best to characterise them as a 

 distinct tribe. 



83. MONOGRAHMA, SchJc. (1809). 



Vernation uniserial, sarmentum slender. Fronds simple, 

 distant, linear, graminoid, 1 to 4 inches high. Veinless. 

 Costa sporangiferous on its disk, or seated in a deep groove 

 on one or both sides, forming a continuous or interrupted 

 linear soris near the apex of the fronds, the margins of 

 which are generally more or less incurved. 



Type. Monogramma graminea, Sclik. 



