1909-10.] Flora of Scottish Lakes. 153 



east and we-st sides the loch is surrounded by agricultural land. The 

 bottom of the loch at the north and west sides consists of deep black mud, 

 but at the south and east sides the bottom is less muddy, and in many 

 places is formed of firm sand. From near the margin to some distance out 

 the average depth of water is from 3 to 5 feet, but as the middle is 

 approached the depth increases somewhat, never, however, exceeding 7 feet. 

 The water is non-peaty and clear, but has a stagnant appearance, which may 

 be described as dead in comparison with the sparkling water of a pellucid 

 highland loch. It is probably rich in plant food-salts, and in consequence 

 of such favourable chemical and physical conditions the whole of the 

 bottom of this loch is more or less overgrown with plants. The marginal 

 swamp vegetation (figs. 89 and 90) is chiefly composed of associations of 

 the following species : — Scirpus lacustris, Equisetum limosum and its var. 

 fluviatile, Phragmites communis, Heleocharis palustris, Carex rostrata (in 

 some places a very robust form of this plant occurs with leaves 5 feet 

 long), Hippuris vulgaris, Typha latifolia, Epilobium hirsutum, Menyanthes 

 trifoliata, Sparganium ramosum, and Phalaris arundinacea. At the south- 

 east side of the loch there is a large association of Polygonum amphibium, 

 whose leaves and flowers cover a ver}^ considerable area of the water beyond 

 the marsh (fig. 91). Outside this zone of Polygonum a wide .space is 

 o ccupied by associations of Potamogeton pusillus, P. filiformis, P. pectinatus, 

 Zannichellia palu,stris,var. brachystemon, Myriophyllum spicatum, Callitriche 

 autumnalis, etc. From the outer margin of this space Ranunculus circinatus 

 reaches the surface even from a depth of 7 feet, and continues to the 

 opposite side of the loch, but nearer the village this species thins out some- 

 what, and there. Ranunculus Baudotii becomes the dominant plant. The 

 white flowers of these two species and the floating leaves of the latter 

 entirely cover the surface of the water over a large area (fig. 92). Although 

 these two species of Ranunculus were growing together very freely in some 

 parts of the loch, no form was found that might be considered a hybrid 

 between them. 



Looking across the loch from the village to the south-east corner, the 

 spectacle presented by the surface-flowering species was unicjue. Tlie 

 expanse of white Ranunculi, followed by the gorgeous pink of the Poly- 

 gonum, backed by the dark foliage of the deciduous trees, to which a skirt- 

 ing of paler green was afforded by the marginal associations of Phragmites 

 and Typha, and illuminated by the refulgence of a cloudless sky, gave such 

 a combination of vivid colour contrasts, harmoniously pleasing to the eye, 

 as can rarely be seen in this country. 



All the plants mentioned as occurring between the a.ssociations of Poly- 



