FLORA OF SCOTTISH LAKES 
241 
Mochrum Loch is half a mile south of the last-mentioned, but is 
much larger, being about one and a half miles long by nearly one- 
third of a mile broad. The north and north-east sides are wooded, 
chiefly with coniferous trees. There are numerous islands scattered 
over the loch ; these also are wooded, and give a pleasing feature to 
the otherwise bare scenery. There is very little shore to this loch, 
merely a narrow strip of rocks or stones intervening between the 
water and the moor or wood ; neither are there any sandy bays, but 
occasionally there is a stretch of peaty shore. The outline is very 
irregular. The loch is very shallow, the average depth being only 
7 feet, and the bottom is frequently rocky. Excepting where rocky, 
the bottom is covered with plants. The water is clear, scarcely peaty, 
and the bottom can be seen through 7 feet of water even in dull 
weather. It is difficult to account for the very slight peatiness of the 
water of this and neighbouring lochs. As they are situated in the 
midst of a spongy peat moor, one would expect to find the water quite 
peaty. As no burn of considerable size enters either this or Castle 
Loch adjoining, presumably they are fed chiefly by springs which 
may, of course, have no connection with the water of the moor. It is 
probable, however, that some constituent, such as an alkali, of the under- 
lying rock may neutralise the peat extract, thus rendering the water 
clear ; the presence of certain calciphilous plants, e.g. Eupatorium 
Cannabinum, suggests lime also. 
A large number of plants are recorded from this loch in the 
original paper ; some of these are species that are not usuallv found 
in lochs on peat moors, and their presence here is no doubt due to 
the neutralisation of the acid humus in the water. The maro-inal 
flora is rather scanty, as there are no large associations of dominant 
marsh plants. The Bryophytes of the shore, with the exception of 
Hypnum cupressiforme which covers rocks, and Sphagnum sp. in 
peaty places, are not abundant. 
Castle Loch is half a mile west of the last-mentioned, which it 
much resembles. There are a few trees at the north end and on one of 
the islands, which also has upon it the remains of a small castle. The 
surrounding country is bare, open moor. This loch is studded with 
numerous rocky islands, the largest being occupied by cormorants 
hundreds of which breed there. The shores are rocky, and the bottom 
is rocky nearly everywhere. The water is clear like that of Mochrum 
Loch, and the average depth is 6J feet. I carefully examined the 
bottom of this loch, as well as the stormy nature of the w^eather would 
allow, but could obtain no plants from the water, save Fontinalis 
antipyretica and F. squamosa, which are abundant on the rocks. 
The bottom appears to be quite destitute of plants, save the two 
species just enumerated. This is remarkable, especiallv when the 
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