184 THE FRESH-WATEH LOCHS OF SCOTLAND 
Equisetum arvense, Z., and E. palustre, L., are occasionally found 
overgrowing sandy or stony shores, in which case, unless 
sheltered by other vegetation, they are always prostrate and 
dwarfed, and sometimes form a sward. 
MARSILEACE.E 
Pilularia globulifera, L., VI. Rare, but occasionally very abundant 
— at Loch Dernaglar, for example. 
LYCOPODIACE.E 
Isoetes lacustris, L., I., IV., V., VL Very general in the peaty hill 
lochs, but neither so abundant nor so variable in form in the 
southern Areas as in Area 1. It usually forms a bottom 
carpet at depths of from 2 to 20 feet. In some lochs of the 
Ness Area these specimens are about 4 or 5 inches long, with 
stout, erect leaves, forming stiff little plants. In other places, 
apparently under similar conditions but with darker peaty 
water, the leaves are 18 inches long, weak and recurved. 
CHARACEiE 
Messrs H. and J. Groves most kindly gave me the benefit of their 
unrivalled knowledge of these plants, and identified a number 
of difficult forms. On the whole, the Characeas are less 
abundant in Areas IV.-VI. than in Areas I.-III. ; they are 
also abundant in VII. 
Nitella opaca, Ag.^ I., IV., V., VI. , VII. Generally distributed in 
peaty lochs. In Area I. it occurs at a greater depth, namely 
30 feet, than any other plant, save Fontinalis antipyretica. 
In Areas IV.-VII. I have never dredged it from a greater 
depth than about 16 feet, nor, indeed, have I found any of the 
higher plants at a much greater depth in these Areas. Reasons 
for this will be given on subsequent pages. Slender forms, 
approaching var. attenuata, H. J. C, occur in Loch Ness, 
and others of that Area. 
Nitella translucens, Ag., I., VI. Rare; only observed at Loch 
Meiklie in 8-10 feet of water, and at similar depths in the 
Mochrum district. A very large form in a barren state, 
extremely like translucens, was referred by Messrs Groves to 
N. flexilis, or N. opaca. It was abundant in Loch Ken and 
Woodhall Loch, at 6-8 feet deep. 
Chara aspera, Willd.^ II., III., V., VII. Frequently abundant in 
lowland non-peaty lochs, or in lochs, that receive the drainage 
of villages. Sometimes it is incrusted with lime. In some 
lochs this plant occurs in prodigious quantity. In Loch 
