154 Proceedings of the Royal Society of Edinburgh. [Sess. 



gonuin and Ranunculus are also abundant at otlier parts of the loch. 

 Zannichellia palustris, var. brachystemon, occurs in extraordinary quantity 

 on the deep black mud at the west side, whilst Myriophylluin spicatum is 

 so plentiful in some places, particularly on the east side, that the surface of 

 the water appears crimson with its flowers. Callitriche autumnalis occurs 

 chiefly in small patches a yard or less across, but in a few places considerable 

 areas of the sandy bottom are covered with it. Lemna trisulca is extremely 

 abundant in shallow water, especially at the north side near the village. 

 Large masses of Cladophora flavescens and Enteromorpha intestinalis were 

 floating about in many places ; indeed, I have only seen such a prodigious 

 quantity of the last mentioned at one other place in Scotland, namely, at 

 Duddingston Loch, near Edinburgh. In some places a species of Nostoc was 

 abundant, floating in masses amongst the vegetation of the margin. A 

 single specimen of Hippuris vulgaris was gathered here, having the nodes 

 in the form of a continuous spiral from base to apex. Considering the 

 shallowness of the loch and the other apjDarently favourable conditions, it 

 seems astonishing that the reeds which grow so luxuriantly at the margin, 

 particularly Scirpus lacustris, Phragmites communis, and Equisetum limosum, 

 have not overgrown it almost completely. 



Besides those already mentioned, the following plants were plentiful at 

 this loch : — Chara aspera and its var. capillata, Potamogeton crispus, P. 

 perfoliatus, P. obtusifolius, Lemna minor, Caltha palustris. Slum angusti- 

 folium, Comarum palustre, Epilobium tetragonum, Mimulus Langsdorffii, 

 Myosotis palustris, Veronica scutellata, Mentha aquatica, M. sativa, 

 Equisetum arvense, E. palustre. Ranunculus Flammula, Juncus acutiflorus 

 and J. eflusus. There are a few common bog mosses, but such are not 

 abundant, as favourable situations are scarce. 



Halton Reservoir is a small, irregularly sliaped sheet of water situated 

 about 2 miles north of Largo. It has been formed by the widening of 

 the natural gorge of the Halton Burn and by the construction of a dam at 

 the lower end. At the time of my visit the water had fallen about 12 

 feet below the full water level, leaving upon the exposed mud the remains 

 of a number of aquatic plants. Some of these were growing in terrestrial 

 form upon the mud, e.g. Myriophyllum spicatum, Polygonum amphibium. 

 Ranunculus peltatus, Potamogeton natans, Callitriche stagnalis, etc. In 

 some places the mud was thickly covered with dead remains of Chara 

 fragilis, which is extremely abundant there. A large quantity of the same 

 species was still flourishing in the water, which under conditions of normal 

 water level would be at a depth of about 14 feet. Gnaphalium uliginosum 

 is very abundant, and forms a sward upon the sides near the full water level. 



