122 FLORA OF ARROCHAR MOUNTAINS. 
NARDUS STRICTA, L. 
One of the most abundant moorland grasses, and dominant over 
a large part of the hillsides, forming the characteristic “ nardus- 
moor.” It ascends to over 2,000 feet, but the exact limits of 
altitude have not been ascertained. 
HYMENOPHYLLUM TUNBRIDGENSE, Sm. 
In the ‘Clydesdale Flora” this species is mentioned as 
occurring on the ‘‘ banks of Loch Lomond at Luss and Tarbet.” 
As I do not know the exact locality of the stations referred to, I 
am unable to say whether the latter comes within the boundary of 
the district under consideration. 
HYMENOPHYLLUM WILSONI, Hook. 
Shady rocks and roots of trees, very common. This fern is 
plentiful in the wooded parts of the banks of mountain streams. 
Ascending to 2,500 feet on Ben Arthur. 
PTERIS AQUILINA, L. 
Dominant over large areas on the hillsides in dry, open 
situations ; also frequent in the woods. The bracken is a conspic- 
uous feature on the hills up to about 1,000 feet, shortly above 
which altitude it stops rather abruptly, the resulting change in the 
aspect of the vegetation being quite a striking one. As was 
pointed out by Watson long ago, this altitudinal limit of the 
bracken may be said to mark the boundary between the lowland 
and the alpine flora. The limit, so far as the Arrochar mountains 
are concerned, may be said to be about 1,200 feet, which is found 
to be fairly constant by comparison at different points in the 
district. Here and there, however, it extends, in depressions on 
the hillsides, to a higher elevation, the highest point noted being 
1,600 feet on Ben Narnain. 
CRYPTOGRAMME CRISPA, Br. 
Alpine.—Very abundant on Ben Narnain, from 2,600 feet to 
the summit. Also found on Ben Ime, at an altitude of 3,200 feet. 
Not reported from the other hills. 
BLECHNUM BOREALE, Sw. 
Common in woods and amongst rocks throughout the district. 
Ascends to 3,300 feet on Ben Ime. 
