FLORA OF SCOTTISH LAKES 
203 
always almost or quite destitute of plants ; whilst trees are entirely 
absent. The plants that flourish at one or another of these lochs are 
as follows : — Littorella lacustris, Lobelia Dortmanna, Isoetes lacustris^ 
Fontinalis antipyretica, Chara fragilis, var. delicatula, Nitella opaca, 
Juncus fluitans, Callitriche hamulata, Potamogeton natans, P. poly- 
gonifolius, P. lucens, Myriophyllum alterniflorum, Utricularia inter- 
media, Sparganium minimum, Glyceria fluitans, Menyanthes trifoliata, 
Comarum palustre, Equisetum limosum, Heleocharis palustris, Carex 
rostrata, C. Goodenovii, C. aquatilis, C. binervis, C. dioica, Eriophorum 
vaginatum, E. polystachion, Triglochin palustre, Juncus effusus, J. 
articulatus, Caltha palustris, Ranunculus Flammula, Hydrocotyle 
vulgaris. Sphagnum acutifolium, S. cuspidatum, var. plumosum, 
Hypnum stramineum, H. trifarium, Rhacomitrium aciculare, Scapania 
undulata, Nardia compressa, Batrachospermum moniliforme, Zygnema 
Vaucherii, etc. 
Crossing Glen Moriston, through which flows a splendid river, a 
desolate mountain region is entered, remarkable for the great number 
of its lochs. With the exception of dwarf birch or mountain ash 
on the islands of a few of them, their shores are treeless and frequently 
entirely devoid of vegetation, excepting on the western side. Their 
waters are without exception peaty, often extremely so. Occasion- 
ally Betula nana is found spreading over a rocky shore. This plant is 
very abundant on the moors of the district, and is often of considerable 
size, the largest specimens having stems as thick as one's wrist ; they 
are, however, always prostrate. The lochs of this extensive region, 
containing about 100 square miles of mountain and moor, are 
characterised by a general paucity not only in variety, but frequently 
also in quantity, of phanerogamic plants. It often happens that the 
plants, particularly those of the littoral zone, are very much dwarfed. 
A small terrestrial form of Sparganium minimum grows at the margin 
of some of these lochs. Dwarf forms of Castalia speciosa and 
Menyanthes trifoliata, sometimes growing on exposed peaty mud, are 
frequently met with. The most abundant marsh plants are Carex 
rostrata, C. filiformis, C. Goodenovii, and Equisetum limosum. 
These sometimes cover very considerable areas of marshy ground, 
but, unless there is some exceptional condition present, such associa- 
tions never occur on the eastern shores. At I^och sC Mheig, which 
is sheltered from westerly winds by hills, the marginal vegetation is 
encroaching upon the water in crescent formation on all sides of the 
loch. This is due to the wind-sheltered position, to the shallow and 
regular, basin-like inclination of the bottom, and to the detrital 
matter brought into the loch by a burn. In this particular case the 
conditions are exceptional for favouring marsh development on the 
eastern side ; the plants concerned are chiefly Carex rostrata and 
