110 HISTORY OF BEITISH FERNS. 



from the great development of the lowest pair of pinnae ; and 

 they are remarkable for the comparative length of the 

 slender stipes, which is about twice as long as the leafy 

 portion. The fronds are tripinnate in the lower part, and 

 bipinnate upwards, the pinnae spreading, and standing op- 

 posite in pairs, the lowest pair considerably larger than the 

 next above, and unequally developed, the inferior side being 

 very much larger than the superior ; this disproportion is 

 not maintained to the same extent in the upper portions of 

 the frond. The lower pinnae, on the inferior side, are first 

 divided into ovate or lanceolate pinnules, and these are 

 again cut into a second series of pinnules, of an ovate or 

 oblong form, these ultimate pinnules being coarsely and 

 irregularly notched or toothed; on the upper side, the 

 pinnules correspond with the secondary pinnules of the 

 lower side. The inferior pinnules of the next pair of pinnae 

 also correspond in size, outline, and subdivision with the 

 secondary pinnules of the lower pimi83; and above this 

 the parts become gradually smaller and less divided up to 

 the apex of the frond. 



The whole texture of the fronds is delicate and herba- 

 ceous, as in the more common species, and hence the veins 

 show very distinctly. In the ultimate pinnules the central 



