1909-10.] Flora of Scottish Lakes. 113 



level. It is 68 feet deep, and is situated in a somewhat open and wind- 

 exposed position among grass-covered mountains. Its surroundings are 

 treeless, except for the plantation about a small fishing lodge at the south- 

 west end, below Craigronald, which rises immediately from the .shore of the 

 loch. The water is very clear, and but slightly peaty. The shore is rocky, 

 with the exception of numerous baj^s of white syenitic sand. The exposed 

 littoral rocks bear a number of common Bryophytes and lichens, but to no 

 great extent, the most abundant being Hyocomium flagellare, Hedwigia 

 ciliata, Grimmia apocarpa, and Rhacomitrium aciculare. The aquatic flora 

 is very poor in species, and the semi-a(|uatic plants of the shore are also poor 

 in species and in numbers, the greater portion of the shore being almcst 

 devoid of such plants. At the north end there are associations of Phragmites 

 communis, Juncus lamprocarpus, and J. acutiflorus ; a little bay on the east 

 side has also a quantity of the first mentioned. On the north-west margin 

 there are associations of Carex rostrata and Equisetum limosum. Groups 

 of Heleocharis palustris and dwarf specimens of Ranunculus Flaminula 

 occur here and there all around the loch. Juncus alpinus and a dwarf form 

 of Heleocharis palustris (p. 8.5) grow upon the drier parts of some of the 

 sandy bays. In certain of these bays the copious sand is blown up into 

 miniature dunes capped with Calluna, etc., resembling those of a sandy 

 seashore on a small scale. The bottom is for the most part very rock}^, 

 but there are considerable areas of sand or gravel extending from the margin 

 to a depth of 8 or 10 feet. These areas are usually more or less carpeted 

 with Littorella lacustris. Lobelia Dortmanna, and Isoetes lacustris, most of 

 which are more or less overgrown with Algae, chiefly Batrachospermum 

 vagum, Ulothrix sequalis, Binuclearia tatrana, etc. (p. 96). These plants, 

 however, bear no external evidence of injury by the Algse, although Nardia 

 emarginata and Scapania undulata, both of which grow abundantly on sub- 

 mersed rocks, were much injured by the dense growth of such epiphytes 

 upon them. Fontinalis squamosa and F. antipyretica occur in abundance 

 upon the submersed rocks of the margin from the surface to 3 or 4 feet 

 deep. In many places Juncus fluitans is extremely abundant from 2 to 5 

 feet deep. In some parts, particularly at the south end. Sphagnum subse- 

 cunduip (p. 90) and Heterocladium heteropterum (p. 93), mixed with 

 Scapania undulata, w^ere abundant at the bottom from 2 to 8 feet deep, an 

 uncommon situation for such plants. They may have been brought into 

 the loch by one of the burns in time of spate, and then become adapted to 

 the submersed environment. 



I could obtain no living plants in this loch beyond a depth of about 10 

 feet, not because of the presence of vegetable detritus, nor of the opacity of 



VOL. XXX. 8 



