
















6 THE BRITISH FERNS. 
fringed indusia, on which Roth seems partly to have relied, is too 
trivial for the purpose of generic definition. The remaining character, 
that of the curved arcuate or horse-shoe-shaped sori, is entirely 
foreign to Asplenium, and indicates, as we have already stated, a 
tendency towards Lastrea. Itis on this ground that we definitively 
adopt the genus, excluding, however, the straight-fruited free-veined 
Allantodias which should, in our opinion, be retained in Asplenium. 
The effect of this, though reducing Athyrium considerably, is not to 
restrict it entirely to the forms of Filix-femina, for a considerable 
number of distinct species, from various countries, have a similar 
fructification. 
The species of Athyrium are analogous in habit with those forms 
of the Polypodiee and .Aspidiee, in which the stem assumes the 
form of a short erect or decumbent caudex, which habit is repre- 
sented among the British Ferns by the Polypodium alpestre and the 
Lastrea Filie-mas. There is, indeed, great similarity in habit be- 
tween the Lady Fern, which is to be regarded as the type of 
Athyrium and the Polypodium alpestre ; indeed the latter, as we 
have already pointed out (ante, vol. i. 78), has sometimes a cer- 
tain amount of resemblance to Athyrium even in the fructification, 
which has led to its being constituted by Mr. Newman into a 
distinct genus, called Pseudathyrium. 
The .species of Athyrium have not hitherto been divided into 
sectional groups. "They are found distributed over the whole of 
both hemispheres; and are generally of elegant aspect, our own 
native species fairly claiming precedence in this respeet over all 
other British Ferns. Among the Indian species are some extremely 
beautiful plants, especially Athyrium pectinatum and Athyrium 
Hookerianum, both of which are remarkable for the finely toothed 
segments of their fronds, which in the former, inhabiting Nepal, 
Simla, etc., are lance-shaped in outline, and in the latter found by 
Dr. Hooker in Sikkim, are deltoid or broadly triangular. 
The name of the genus was derived by Roth from the Greek 
athyros, opened, or having an open entrance, alluding to the re- 
pressed indusium. 

