128 Proceedings of the Royal Society of Edinburgh. [Sess. 
clothed with coniferous wood, and there is also a small plantation of the 
same kind on the south side. The loch is therefore wind-sheltered to a 
considerable extent although open to the south-west (fig. 46). The water of 
this loch was low owing to drought at the time of my visit, and the margin 
being gently inclined, a considerable area normally under water was 
consequently exposed. In many places such exposed portions consisted of 
bare peat or mud, but at other parts where the plants, normally submerged, 
readily adapt themselves to terrestrial circumstances — for instance, Littorella 
lacustris, Polygonium amphibium, etc. — the exposed mud was thickly covered 
by them (fig. 47). Here, as in other instances that I have frequently 
observed, sheep were grazing upon the exposed Littorella. The shepherds 
do not approve of this kind of food for their sheep, having an empirical 
belief that “ this grass ” is liable to cause liver-fluke in the animals. When 
one calls to mind the life-history of Distomum hepaticum, it seems quite likely 
that it would very readily occur in the encysted stage upon exposed 
Littorella, and would thus freely gain access to the bile-ducts of sheep that 
had fed upon that plant. Alisma ranunculoides was abundant; many 
specimens of it were flowering at a depth of 3 feet below the surface 
(p. 81); it was also flowering freely in the normal terrestrial condition 
around the margins. The following plants were more or less abundant : — 
Littorella lacustris, Lobelia Dortmanna, Isoetes lacustris, Myriophyllum 
alterniflorum, Apium inundatum, Nitella opaca, Chara fragilis, var. delicatula, 
Juncus fluitans, Ranunculus heterophyllus, Sparganium natans, Utricularia 
vulgaris, Castalia speciosa, Nymphsea lutea, Potamogeton polygonifolius, P. 
natans, Fontinalis antipyretica, Menyanthes trifoliata, Polygonum amphib- 
ium, Comarum palustre, Alisma ranunculoides, Carex rostrata, Carex flava, 
Heleocharis palustris, Peplis Portula, Montia fontana, the last two in both 
aquatic and terrestrial forms ; Polygonum Hydropiper, Myosotis palustris, 
Juncus conglomeratus, J. acutiflorus, J. effusus, Ranunculus Flammula, Mentha 
sativa, Hydrocotyle vulgaris, Caltha palustris, Senecio aquaticus, Galium 
palustre, Carum verticillatum, Spiraea Ulmaria, Scutellaria galericulata, 
Phalaris arundinacea, and Plantago lanceolata. Hypnum fluitans, H. 
scorpioides, H. cuspidatum, and Fontinalis antipyretica were abundant in the 
water or in wet places, whilst Grimmia apocarpa and Hypnum cupressiforme 
covered the rocks on the east shore ; otherwise Bryophytes were scarce. 
Loch Roan is a small, somewhat triangular sheet of water, 2 miles 
north of Crossmichael. The west, north, and east margins are clothed 
with wood, chiefly coniferous, to the water’s edge, whilst the south shore 
abuts upon meadow-land. Where the shores are gravelly or sandy there 
is little vegetation, but where boggy the usual marsh plants occur (fig. 48). 
