1913-14.] BOTANICAL SOCIETY OF EDINBURGH 283 



longifolia, Linn.; Orchis latifolia, Linn.; Xarthecium 

 ossifragum, Huds. ; Eriophorum angustifolium, Roth : 

 Garex echinata, Mxut. : and Juncus sguarrosus, Linn., in 

 drier situations. 



A few specimens of Salix aurita, Linn., Salix cin&rea, 

 Linn., and Alnus rotundifolia, Mill., also occur here and 

 there. 



Behind the Sphagnum zone the typical moorland plants 

 occupy the drier ground. Erica Tetralix, Linn., is 

 abundant, while Pteris aquilina, Linn., covers large areas 

 of the sloping ground surrounding the pool. Amono- the 

 grasses represented are Agrostis setacea, Curt., and Sieg- 

 Ivagia decumbens, Bernh. 



The distribution of Pilularia in Britain and on the 

 Continent of Europe is referred to in the works of 

 Ascherson and Graebner (1896-98), Gliick (1911), and other 

 authors, and an examination of these records discloses the 

 fact that Pilularia is frequently associated with such 

 plants as Subularia aquatica, Linn., Lobelia Dortmanna, 

 Linn., and Isoetes lacustris, Linn. 



In Belgium, according to Massart (1910), Pilularia 

 occurs in the " district campinien " at an altitude not 

 exceeding 400 feet, while the ponds of this area also 

 yield Subularia and Lobelia. 



In Northern Germany, Graebner (1901) states that 

 Pilularia is more or less confined to the pools of the 

 heather area, and in these situations the same author rinds 

 Lobelia and Lsoetes at a low altitude. In his paper "Om 

 Vegetationem i Nagra Smalandska Sjoar," Carlson (1902) 

 recognises Pilularia as a constituent of the Lobelia and 

 Phragmites associations. Pilularia is also associated with 

 Subularia and Lobelia in several of the Irish lakes 

 (Praeger, 1909). 



In Scotland, the distribution of Pilularia is of particular 

 interest when examined from the point of view of situation 

 and associated species. It is found at low levels in the 

 southern counties, while it ascends to 1000 feet in Perth- 

 shire. In his "Survey of Scottish Lakes," West (1910) 

 describes Pilularia as being very abundant in Loch 

 Dernaglar (Wigtownshire), about 400 feet above sea-level. 

 The aquatic flora of this loch resembles that of the 



