FLORA OF SCOTTISH LAKES 
257 
the bank enters the water without the intervention of a shore. At 
the north and west the shore is flat, and muddy or peaty, and is 
covered with a luxuriant vegetation, whilst there is very little at the 
south shore, and none along the dam. A zone of Equisetum limosum 
extends along the greater part of the north side, intermingled with 
Littorella lacustris, which runs up the shore and forms a dense sward 
in some places. Occasionally considerable areas of exposed mud were 
covered with Juncus fluitans, which was reverting to the terrestrial 
type, J. supinus, which it somewhat resembled. Other normally 
submersed plants were assuming a terrestrial habit and forming a 
meadow-like sward upon the exposed shore, particularly Ranunculus 
aquatilis, Heleocharis acicularis, Polygonum amphibium, Potamo- 
geton polygonifolius, and P. heterophyllus. The normal aquatic 
form of the last-mentioned was very abundant at this loch. Those 
left upon the exposed mud were developing new aerial leaves, similar 
to the coriaceous floating ones, but smaller, the thin submersed leaves 
having completely withered away. At the north-west end a portion 
of the shore presented a remarkable appearance, through being 
covered with dead tussocks of Molinia caerulea, which had been 
drowned during some period when the water-level was abnormally 
high. 
A little to the east of Harperleas is Ballo Reservoir, both being 
situated on an upland plateau which forms the south flank of the 
East and West Lomond Hills. These reservoirs are surrounded by 
moor of the grass or heather type, or a superior pasture-land which 
is due to cultivation. Harperleas Reservoir is treeless, but Ballo has 
a plantation of conifers upon its south-west shore. There are also 
a few plantations in the neighbourhood of the reservoirs, which 
pleasantly relieve the sameness of the moor and add a picturesque 
charm to this pleasant, although small, stretch of upland country. 
Ballo Reservoir has a somewhat pear-shaped outline, with the 
narrow end towards the south-east. It is about a mile long by 
half a mile wide at the broadest part. In general features it much 
resembles Harperleas Reservoir, but there is less variety in the 
species of plants. At the north-west end there is an extensive peaty- 
muddy flat, covered with an association of Juncus effusus. This 
flat area extends out into the loch for some distance, and, in the dry 
season, is exposed by the falling of the water. It is covered with 
Littorella lacustris, Heleocharis acicularis, and Juncus fluitans, all of 
which assume the terrestrial habit when the water has receded. At 
the same end of the loch, })ut nearer the north side, Hydrocotyle 
vulgaris extends over a considerable area and forms a dense sward. 
Equisetum limosum forms a zone along a portion of the north shore, 
as at Harperleas Reservoir, behind which there is a strip of boggy 
17 
