

SSS 二 一 一 > — 
SSS 

118 THE BRITISH FERNS. 
pendulous according to the conditions of growth, linear-lanceolate, 
pinnate. Pinne undivided, numerous, with one of the margins, 
usually the anterior one, bent back from the plane of the rachis, 
and usually crowded, so that when the frond is flattened they 
become overlapping on the upper part of the frond, though distinct 
and sometimes distant below. They are very rigid, with numerous 
small hair-like scales scattered over their under surface; very 
shortly stalked or sessile, lanceolate-falcate, from three-quarters of 
an inch to an inch and a quarter in length in the widest part, 
having an acute point, and an acute auricle at the base on the 
anterior side, the base on the posterior side being obliquely sloped 
or rounded off in all the upper pinnae, but often produced into 
a posterior auricle in the lowest ones, which are shorter, and 
nearly triangular in outline, sometimes even hastate. The margin 
is serrated, and the serratures are tipped by bristle-like points, with 
minute intermediate teeth. 
Venation generally indistinct. There is a pinnately branched 
costa extending to the apex of the pinna, and diverging from it, 
at the very point where it enters the pinna, is a principal branch or 
vein which extends to the apex of the auricle, which vein is pinnately- 
branched on the same plan as the midvein, but on a smaller scale. 
The rest of the veins on each side the midvein are pinnately forked, 
i.e., they are branched, but the branches are so placed that at each 
ramification the vein seems to have separated into two nearly equal 
and but slightly diverging parts. In average specimens there are 
three or four of these ramifications to each of the veins near the base 
of the pinna, then two, and finally one in those near the apex. 
The venules and veinlets are lost in the substance of the frond just 
within the margin, one being directed into each marginal tooth. In 
smaller specimens the number of ramifications in the veins is fewer. 
Fructification on the back of the frond, and usually confined to the 
upper half, though sometimes extending lower down. Sori round, 
indusiate, forming a line on each side the midvein, halfway between 
it and the margin, and also in a similar way a line on each side the 
principal vein extending into the auricle. These sori are of variable 
size, but often large and crowded, and then generally becoming con- 
fluent in age; they are attached to the anterior branch of each 

