Flora of Scottish Lakes. 
153 
1909-10.] 
east and west 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 very considerable area of the water beyond 
the marsh (fig. 91). Outside this zone of Polygonum a wide space is 
occupied by associations of Potamogeton pusillus, P. filiformis, P. pectinatus, 
Zannichellia palustris, 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 unique. The 
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 associations of Poly- 
