GENUS IX. 
ASPLENIUM, Linnaeus. 
SPLEENWORT. 
GEN. CHAR Sort linear oblong or elongate, straight, 
attached along the inner side of the venules. Indusium 
entire or somewhat jagged, opening along its inner side, 
or that nearest the mid-vein. Veins free ; mid-vein some- 
times wanting; venules simple or forked. 
This genus contains two groups, in one of which the 
pinnules or ultimate divisions have a distinct mid-vein, 
branching into simple or forked venules, along the inner 
side of which the sori are produced. In the other group 
there is no mid-vein, but the veins entering at the base of 
the divisions become more or less repeatedly furcate ; the 
soriferous venules being fertile along their anterior or inner 
side. These differences have led to the separation of the 
latter group, for which Mr. Newman proposes the name 
of Amesium. Asplenium septentrionale, the typical 
species of this Amesian section, had, however, been long 
previously separated by Link, under the name of 
Acropteris. The distinctions of these groups, so obvious 
in the few species natives of Britain, are altogether lost 
among exotic species. 
The name has been latinized from the Greek asplenon 
that derived from a, priv., and splen, the spleen a 
