244 THE FKESH-WATER LOCHS OF SCOTLAND 
Plankton organisms are the cause of this turbidity, more especially 
the diatom Melosira granulata. There is neither affluent nor effluent 
to this loch, save a shallow boat canal connecting it with the adjoin- 
ing Black Loch, the water of which is dark and peaty (presumably 
these facts guided the nomenclator of the lochs). The water is there- 
fore more or less stagnant, a condition favouring the increase of 
certain plankton organisms. A feature of both this and the Black 
Loch is the narrow border of Heleocharis palustris that prevails nearly 
everywhere, growing luxuriantly to a height of 3 feet, with very 
large inflorescences. Elatine hexandra grows exposed upon the shore, 
also in the water to a depth of 2 feet. Myriophyllum alterniflorum 
and M. spicatum both grow abundantly in this loch, which is 
rather unusual. Amongst several species of Potamogeton a very 
large form of P. lucens should be mentioned, and a beautiful form of 
P. crispus with broad leaves which have a wide red midrib ; the latter 
is found in other lochs of this neighbourhood. Bryophytes are 
scarce. 
Black Loch adjoins the last-mentioned. It is over a mile long, 
but is narrow, particularly at the north-west end. The surroundings 
are similar to those of the White Loch, but the water is brown and 
peaty, and, although plankton organisms abound, the bottom can be 
seen through S feet of water when looking ov^er the side of a boat. 
The shore is similar to that of the White Loch, but the flora is more 
varied. Usually water from 7 to 10 feet deep occurs within a few 
feet of the shore. To a depth of about 7 feet a few of the usual 
plants may be found, but they are by no means abundant, as the 
bottom is generally stony. At greater depths than 7 feet I obtained 
no living plants, but an abundance of dead vegetable remains, 
as at other shallow peaty lochs with no current to scour them. 
At the north-west end there is a circular basin connected with the 
loch by a narrow channel. This is almost surrounded, excepting on 
the south-west side, by a narrow border of Phragmites communis^ 
Typha latifolia, and Scirpus lacustris ; whilst the surface is largely 
overgrown with Nymphsea lutea. At the south-east end of the loch 
there is a marsh with the usual common plants. Bryophytes are 
everywhere scarce. 
Cults Loch is half a mile east of the last-mentioned. It is a 
small circular loch, wdth non-peaty water, surrounded by meadow- 
land. At the north-west and south-east sides there are small bogs ; 
at other places a narrow zone of marsh chiefly occupied by Juncus 
eff'usus intervenes between the water and the pasture. There is little 
of botanical interest here, beyond a number of common plants. 
Loch Magillie is about a mile south-west of the White Loch. 
It is a small oval loch with clear water which is not peaty, and with 
