ONE-SIDED FILMY FERN. 181 
y-Mawddach, near Llaneltyd ; it also occurs, growing 
in company with Tunbridgense, in the Vale of Fes- 
tiniog. In Cardiganshire, on rocks close to Pont 
Bren, or the Parson’s Bridge. In Brecknockshire, it 
is common among the mountains. In Glamorganshire, 
on rocks some way below the Melincourt fall, and 
also on rocks near the Scud-einon-Gam. Returning 
into England, we find this species in two western 
counties: in Devonshire, it occurs, in company with 
Tunbridgense, upon rocks and large blocks of granite 
adjoining the Plym, above Shaugh Bridge, and in much 
greater abundance at Westman’s Wood, Dartmoor; 
Wood, South Devon, In Cornwall, at Granite Tor; 
at Carn Brea, near Redruth, and in abundance at 
Rough Tor, near Camelford. In Ireland this fern is 
much more common than in England, and grows with 
a beauty and luxuriance that I have not witnessed 
elsewhere; it is more generally distributed over the 
island than Tunbridgense, and whereas Tunbridgense 
exhibits something like a preference to shade, warm 
and shelter, Unilaterale establishes itself on bleak and 
exposed rocks. I subjoin a few localities : in Donegal, 
on the Ennishowen mountains; in Londonderry ; in 
Antrim, by the Glenarve river, near Cushendall; in 
Down, in Tullamore Park and on the Mourne moun- 
tains; in Fermanagh, near Florence Court; in Gal- 
“way; in Connemara; and I have seen specimens from 
