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 j)eat 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 polj^gonifolius, 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. eflusus. 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 Brj^ophj^tes 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). 



