1909-iO.] 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 .stonj^ 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 f 

 mile long, inade 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 eff"usus, 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 fontana, 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 liniosum, 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 

 a([uatilis, 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 eff"usus, J. acutiflorus, Cnicus palustris, 

 Deschampsia ciespito.sa, Spira3a 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 ^Mj-riophyllum 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. 



