136 HYilEXOPHYLLUM WILSOXI. 
HYMENOPHY'LLUM WILSO'NI. 
THIS owes its specific name to being first distinguished 
from Hymenophyllum Tunbridgense by Mr. W. Wilson. 
It is called H. unilaterdle by some botanists, in allusion 
to the lobes of the leaflets being on one side. We 
believe it to be the variety of H. Tunbridgense described 
by Bolton as having its " fructification on naked fruit- 
stalks," and which he found on rocks under Dolbadern 
Castle, near the lake of Llanberris, and on the rock 
called Foal-foot, on Ingleborough, in Yorkshire. 
Root thread-like, brown, slightly scaly, creeping, and 
producing a few fibrous rootlets. Fronds from one to 
three inches high ; stalk stiff, smooth, round, winged at 
the top. Leaflets clothe two-thirds of the stalk, dark 
green, alternate, bent-back, lobes curved downwards, 
and spreading horizontally rather than vertically as 
they do in H. Tunbridgense; lobes oblong-oval, sharply 
toothed, and on the upper side of the leaflet only. 
Fructification is placed as in H. Tunbridgense, but 
unlike that is stalked ; its outer case (involucre) is 
egg-shaped, with swollen convex valves meeting at 
their edges. The fructification curves forward in a 
direction opposite to that in which the lobes of the leaf- 
lets are curved. 
In England it has been found near the waterfall 
above Ambleside ; at Black Bocks of Great End, in the 
Scawfell Range, and at Scale Force near Buttermere ; 
and at Greenfield near Saddleworth, and near Silverdale. 
