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



antly to a height of 3 feet, with very large inflorescences. With these, 

 Radicula palustris, Myosotis palustris, Polygonum Hydropiper, P. Persicaria, 

 P. amphibium, Phalaris arundinacea (fig. 71), Mentha aquatica, Juncus 

 acutiflorus, Caltha palustris, and Ranunculus Flammula are the chief plants 

 of the margin. Elatine hexandra grows exposed upon the shore, also in 

 the water to a deptli of 2 feet. Myriophyllum alterniflorum abounds to a 

 depth of 6 or 7 feet ; M. spicatum is abundant from 4 to 7 feet deep. Chara 

 fragilis, var. delicatula, occurs sparingly from the margin to a depth of 6 feet. 

 The following species of Potamogeton are all abundant, especially at the 

 north-west end : — P. crispus, a beautiful form, with broad leaves, havnig a 

 wide red midrib ; the same form is also found in other lochs of this neigh- 

 bourhood ; P. Zizii, P. perfoliatus, P. prajlongus, P. obtusifolius, P. pusillus, 

 and a very large form of P. lucens. Callitriche autumnalis and Ranunculus 

 peltatus occur sparingly. Bryophytes are scarce. 



Black Loch, as already explained, adjoins the last mentioned. It is 

 about 1;\ miles long, and has a maximum breadth of ^ mile, but it 

 narrows considerably towards the north-west end. The surroundings are 

 similar to those of White Loch, but the water, which has a maximum depth 

 of 50 feet, is brown and peaty ; and although plankton organisms abound, 

 the bottom can be seen to a depth of 8 feet when looking over the side of a 

 boat. The shore is similar to that of White Loch, but the littoral flora is 

 more varied. Usually water from 7 to 10 feet deep, or even deeper, occurs 

 within a few feet of the shore. To a depth of about 7 feet a few of the 

 usual submersed plants may be gathered, but they are by no means abun- 

 dant as the bottom is generally stony. At greater depths than 7 feet no 

 living plants can be found, but an abundance of dead vegetable remains, as 

 at other shallow peaty lochs with no current to scour them. Cladophora 

 glomerata covers stones abundantly from 2 to 7 feet deep. Fontinalis anti- 

 pyretica occurs sparingly in similar positions. Myriophyllum alterniflorum 

 grows from the margin to 7 feet deep, but is not very abundant. Littorella 

 lacustris is found in places about the shores, but appears to be neither 

 general nor plentiful, nor does it enter the water beyond a depth of a few 

 inches, probably because of the constancy of the water level. Nymphaea 

 lutea is abundant, and Potamogeton Zizii is scarce. No other submersed 

 plants were observed in the main bod}^ of the loch. At the north-west end 

 there is a somewhat circular basin, connected with the loch by a narrow 

 channel. This is almost surrounded, excepting on the south-west side, by 

 a narrow border of Phragmites communis, Typha latifolia, and Scirpus 

 lacustris, whilst the surface is largely overgrown with Nymphaea lutea. 

 On the south-west side of this basin there are small associations of marsh 



