1010 Proceedings of Eoyal Society of Edinburgh. [sess. 
is very peaty, presents little of botanical interest. Originally 
there existed on the site a small tarn and extensive peat diggings. 
The dam is at the north end. 
Lochan Dubh, at Dunlichty, is a small peaty pool entirely 
surrounded with coniferous forest; near the margin the sandy 
bottom is entirely covered with a dense tangled mass of Hypnum 
fluitans, var. Arnellii, Sphagnum cuspidatum, var. plumosum, 
Nardia emarginata, and Zygogonium ericetorum, purple var. At 
other places Littorella lacustris, Myriophyllum alterniflorum, and 
Menyanthes trifoliata occupy considerable areas, while the shores, 
on the western side especially, have colonies of Carex rostrata, 
C. aquatilis, and Juncus effusus. In the rear of the latter a large 
tract, but slightly elevated above the surface of the loch, is 
occupied by a pure formation of Erica tetralix, the depressions 
filled with Sphagnum subsecundum, var. viride (fig. 75). 
Loch a Chlachain is 683 feet above sea level. The surrounding 
country is extremely wild and rocky. The water is clear, owing 
to the fact that the peat area drained by it is comparatively small. 
This loch drains Loch Duntelchaig, which in turn drains Loch Ceo 
Ghlas. The whole catchment area of these lochs consists greatly 
of bare rock, covered in many places with enormous patches of 
Arctostaphylos Uva-Ursi. Heather and peat is often restricted to 
interstices between the bare boulders, consequently the water of 
these lakes is unusually clear, but doubtless very poor in plant 
food-salts. The rocky nature of this area, together with the 
spreading habit of Arctostaphylos Uva-Ursi, are illustrated by 
fig. 76. The rock-bound shore is not conducive to a littoral flora; 
plants are consequently scarce, excepting at the west end, where 
the shore is flat owing to detrital matter brought into the lake 
by the inflowing stream. This portion is covered with vegetation, 
Equisetum limosum, Phragmites communis, Carex rostrata, C. 
aquatilis, Eriophorum polystachion, and E. vaginatum occupying 
considerable areas. The other plants of this loch are Littorella 
lacustris, Lobelia Dortmanna, Isoetes lacustris, Potamogeton lucens, 
P. natans, Sparganium natans, Juncus fluitans, Callitriche 
hamulata, ISTitella opaca, Chara fragilis, var., Myriophyllum 
alterniflorum, Juncus effusus, J. articulatus, and a few of the 
usual and common shore plants scattered here and there. 
