1909-10.] 
Flora of Scottish Lakes. 
155 
Except a few common marsh plants about the affluents at the west and 
north, nothing else of botanical interest was noticed here. When the 
water is low, the steep rocky or stony sides give this place the appearance 
of a flooded quarry, which indeed it is. 
Clatto Reservoir is situated about 3 miles south of Springfield, at an 
elevation of over 500 feet above sea level, in an upland district of which 
Clatto Hill is the highest point. It is a narrow sheet of water about J 
mile long, made by building a dam across the east end of the valley through 
which flows the Ceres Burn. The water is clear, and not peaty, and is 
bordered in many places by a zone of marsh, or a narrow strip of sandy- 
muddy or stony shore may intervene between the water and the grassy 
banks. Skirting a portion of both the north and south shores there are 
plantations of coniferous trees, otherwise the surrounding country is mostly 
of the agricultural type. At the east end, where the dam is, deep water 
occurs, and this part bears no plants, but at the shallow west end there is 
an extensive development of marsh. The vegetation of this marsh consists 
chiefly of the following species : — Juncus effusus, J. acutiflorus, Deschampsia 
csespitosa, Spiraea Ulmaria, Carex Goodenovii, C. rostrata, Heleocharis palus- 
tris, Sparganium ramosum, Menyanthes trifoliata, and Comarum palustre. 
These species occur in definite associations in accordance with the amount 
of water, whilst the minor plants of this formation are — Cnicus palustris, 
Stachys palustris, Ranunculus Flammula, R. hederaceus, Caltha palustris, 
Callitriche stagnalis, Montia f on tana, Hydrocotyle vulgaris, Galium palustre, 
Mentha sativa, M. aquatica, Radicula officinalis, Glyceria fluitans, and Veronica 
Beccabunga. In deeper water, beyond the associations above mentioned, a 
large area is occupied by Equisetum limosum, with which are mixed, here 
and there, small patches of Hippuris vulgaris. These advance into water 3 
or 4 feet deep, and succeeding them there are associations of Ranunculus 
aquatilis, Sparganium natans, Potamogeton natans, P. pusillus, P. obtusifolius, 
and Myriophyllum spicatum, running out into water 7 or 8 feet deep. 
The south shore has a border of marsh along a considerable portion of 
its length, chiefly composed of Juncus effusus, J. acutiflorus, Cnicus palustris, 
Deschampsia caespitosa, Spiraea Ulmaria, Carex Goodenovii, C. rostrata, and 
Heleocharis palustris, the last being the most abundant, and occupying a 
zone from 10 to 20 feet wide outside the other species. In deeper water, 
beyond the zone of Heleocharis palustris, there are patches of the submersed 
plants mentioned above, Potamogeton natans and Myriophyllum spicatum 
being the most abundant. Here and there, where the border of marsh is 
absent, the shore is frequently carpeted with Littorella lacustris, whilst 
Heleocharis acicularis is scarce. 
