FLORA OF ARROCHAR MOUNTAINS. 113 
Inveruglas, where the bushes grow to a height of about four feet, 
and form a dense growth several acres in extent, to the exclusion 
of other plants. 
BETULA ALBA, L. 
Very common all over the lower parts of the hills, except in 
Glen Croe, which is mostly treeless. The birch becomes dominant, 
and forms an almost pure woodland at altitudes above the limit 
of the oak-woods. It is an eminently social species, single, 
isolated trees being rarely found at any great distance from the 
rest. The birch-woods attain their highest altitude on Ben 
Vorlich, the upper limit being 1,500 feet. 
ALNUS GLUTINOSA, Gertn. 
Very abundant on the banks of Loch Lomond, and common in 
the woods elsewhere. Groves of alder occur here and there on 
the hillsides, notably on Crois above Coiregrogain. These, how- 
ever, are nowhere of great extent. The species attains an altitude 
of 1,000 feet on Ben Vorlich. 
Carpinus Betrutus, L. 
A tree of this species was noted on the banks of the Glen Loin 
burn. 
CoryLus AVELLANA, L. 
Common in the woods, at low elevations, chiefly associated 
with oak and alder. Ascends to 600 feet on Ben Vorlich. 
Quercus Roesovr, L. 
The dominant tree in the natural woods on Loch Lomond side. 
Although mostly in the form of “scrub,” there are occasional fine 
specimens of oaks to be seen in the district. This tree does not 
ascend to high altitudes on these hills, the upper limit being about 
1,000 feet. 
CASTANEA SATIVA, Mill. 
A few specimens occur on the banks of the Glen Loin burn 
above the bridge at Arrochar—evidently introduced. 
FAGuS SYLVATICA, L. 
Common in the Loch Lomond woods, and on the hillside 
behind Arrochar. Not on the mountains. 
H 
