











































2 THE BRITISH FERNS. 
be little doubt that it was the examination of the plants in this state 
which led some botanists to refer the Lady Fern to the Aspidiee, 
with which, the prevalence of linear sori, however, shows it to be 
widely at variance. ` | 
As originally constituted by Roth, the genus Athyrium appears to 
have been mainly founded on the short ovate sori, as distinguished 
from the more decidedly linear fructifications of Asplenium, and on 
the indusium being semilunate, fringed, lax, and at length repressed. 
Besides the forms of Lady Fern, Roth himself included only Asple- 
nium fontanum and Halleri, two names for one species, which he 
probably referred to his new genus on account of its very short sori. 
Presl also, in characterising this genus, relied chiefly on the usually 
curved, rarely straight, short oblong sori, and on the presence of a 
convex or inflated indusium, and he includes in it the Allantodie 
of Brown, as also does Professor Fée. This latter appears to be the 
general view as to the limits of the group, whether adopted as a 
distinct genus or a section of Asplenium, the species of Alantodia 
with free veins, Asplenium umbrosum for example, being usually 
associated with the Lady Fern. 
To us it appears that Athyrium proper, of which the Lady Fern 
is the type, is abundantly distinguished from Asplenium; but, with 
one exception, the characters above alluded to, are not those which 
we think should be relied on for its diserimination. In the shortness 
of the sori, there is nothing sufficiently fixed and definite to serve 
as a character distinguishing the group from Asplenium itself, in 
which the greatest variety as to the length of the sorus occurs ; 
and accordingly we do not concur in the separation from Asplenium, 
of the free-veined species of Allantodia and their removal to Athy- 
rium. The fringed margin of the indusium again, is altogether too 
trivial a character; nor is the vaulted or convex nature of the 
indusium a character of sufficient value or .constaney to have so 
much importance assigned to it. It is in the semi-lunate or curved 
form of the sorus, to which various pteridologists have referred, 
that the most important characteristic of structure is indicated, 
though not very fully expressed. The constant production of these 
curved sori is, in our opinion, the great distinctive character of the 
genus Athyrium. ` 

