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



Glyceria fluitans, Br. " I., II., Ill," IV., V., VI., VII. Widely dis- 

 tributed, but seldom occurring in great abundance (ante, fig. 95). 



Glyceria aquatica, Wahlb. V., VII. Seldom seen at the lochs, but 

 occasionally it occurs in great abundance : instance Carlingwark 

 Loch, Lindores Loch, and others (figs. 54, 83, etc.). 



Alopecurus geniculatus, L., is very abundant on the sandy-muddy 

 shore of Town Loch, Dunfermline. 



Agrostis vulgaris, With., is very abundant at the same place as the 

 last mentioned, and also at Lindores Loch. Small patches or isolated 

 specimens of these two grasses, with other terrestrial species, are 

 frequently found mixed with the semi-aquatic vegetation of the 

 littoral. Frequently, too, the grass sward of a moor or meadow 

 adjoining a loch enters the water, and, contrariwise, aquatics such as 

 Littorella lacustris leave the water, and compete for terra jirina 

 against the land plants. Aquatic and terrestrial zones of vegetation 

 in such cases are undeterminable. 



EQUISETACE^. 



Equisetum limosum, L. " I., II., III.," IV., V., VI., VII. This is another 

 very abundant plant ; large associations occur at the margins of 

 lochs of all descriptions. The var. fliiviatile (X.) is sometimes found. 



Equisetum arvense, L. Occasionally found overgi'owing sandy or 

 stony shores, in which case, unless sheltered by other vegetation, it 

 is always prostrate and dwarfed. 



Equisetum palustre, L. Occasionally found amongst the marsh 

 vegetation of lowland lochs, and sometimes on sandy-muddy shores. 

 In the last habitat it is always dwarfed and frequently prostrate. 

 Sometimes this and the preceding plant otow together in a dwarfed 

 and semi-prostrate condition as at Loch Leven, in which case the 

 two species are difficult to distinguish from one another. These two 

 species of Equisetum usually occur so sparsely as to be scarcely 

 worth mentioning as constituents of a loch flora. 



MARSILEACE^. 



Pilularia globuiifera, L. VI. Rare, but occasionally very abundant, 

 at Loch Dernaglar for example (fig. 69). 



LYCOPODIACEiE. 



Isoetes lacustris, L. " I.," IV., V., VI. Very general in peaty lochs, 

 but neither so abundant nor so variable in form as in Area I. 



