CHAEACTERS OP TRIBES AND GENERA. 227 



into a few species. In the " Species Filicum " six 

 species only are enumerated ; but having had the oppor- 

 tunity of examining not less than eight species in a living 

 state, has led me to increase the number to about a dozen- 



Sp. N. undulata (Sw.) (v v.). 



OBS. Sir Wm. Hooker unites this with N. tuberosa, but 

 viewing living plants proves them to be very distinct. The 

 fronds of the present species dying down annually, whereas 

 in N. tuberosa they are permanent. 



N. pectinata (Willd.) (v v.) ; N. pendula (Radd.) ; N. 

 exaltata (Sw.) (v v.) ; N. cordifolia (Linn.) ; N. tuberosa 

 (.Bory.)(vv.); N.volubilis(/.m.) ; N.ensifolia (Sw.) (vv.); 

 N. hirsutula (Sw.) (v v.) ; N. biserrata (Sw.) (v v.) ; N. 

 splendens (Willd.) ; N. davallioides (Sw.) (v v.) ; N. abrupta 

 (/. Sm.) (Leptopleura ahrupta, Presl.). 



OBS. This species is a native of Bourbon and is probably 

 not distinct from the preceding one which is a very elegant 

 species, a native of India and Java ; it differs from other 

 species of the genus in the upper pinnse being contracted, 

 which are sinuously lobed, each lacinae and lobe bearing a 

 sorus, furnished with a nearly orbicular indusium, the free 

 exterior margin of which connives with the margin of the 

 lobe, which becomes partially reflexed, and thus forming as 

 it were a bilabiate cyst, analogous to the tribe Dicksonice, 

 which circumstance led Presl to characterise it as a distinct 

 genus under the name of Leptopleura. 



119. ISOLOMA, /. Sm. (1841). 



Lindscea, Hook. Sp. Fil. 



Vernation fasciculate, erect, stoloniferous. Fronds linear, 

 1 to 2 feet long, pinnate ; pinnae oblong, elliptical or lan- 

 ceolate, falcate, coriaceous, the base truncate and sub-auri- 

 culate ; petiole short, articulate with the rachis. Veins 



