84 
Proceedings of the .Royal Society of Edinburgh, [Sess. 
found in non-peaty lowland areas. The typical P. poiygonifolius 
is frequently met with in peaty areas, and often in mountainous 
districts, whilst the two are sometimes seen growing together in all 
kinds of situations. 
Potamogeton poiygonifolius, Pourr. “ I.,” IV., V., VI., VII. The typical 
form is certainly less abundant in non-peaty lochs than the form 
approaching P. natans in size and texture of leaf, etc. 
Potamogeton poiygonifolius, Pourr., var. pseudo-fluitans, Syme. IV. 
Abundant in Loch Recar and others in the same district, as well as 
in the streams. None fertile ( i.e . in September). A very distinct 
variety with elongated, rather pellucid leaves that are beautifully 
netted near the midrib. 
Potamogeton rufescens, Schrad. ( = P. alpinus, Bcdb.). V., VI., VII. 
Sometimes abundant, but not a very common species. The variety 
spathulifolius, Fischer, occurs in Black Loch (p. 168). 
Potamogeton heterophyllus, Schreb. “ III.,” V., VII. In lowland lakes, 
but not a very common plant in these Areas. The var. terrestris, 
Schlecht., occurs at Loch Leven. 
Potamogeton lucens, L. “ I., II.,” IV., V., VI., VII. Frequently 
abundant, and variable in form. The very large forms usually 
occur in non-peaty lochs. 
Potamogeton Zizii, Koch ( = P. angustifolius, Bercht. and Presl.). IV., 
VI., VII. Sometimes very abundant, especially in Area VII. 
Potamogeton crispus, L. “ I.,” V., VI., VII. Not a very common species, 
nor often in abundance, excepting in Area VII. At White Loch, 
Castle-Kennedy, and in other lochs near it, a beautiful form occurs, 
having wide, bright red midribs to the leaves. The var. serratus 
(. Huds .), which has greener, flatter leaves than the type, sometimes 
occurs. 
Potamogeton perfoliatus, L. “ I., II.,” IV., V., VI., VII. Frequent, and 
sometimes abundant. 
Potamogeton prselongus, Wulf. “ I.,” IV., V., VI., VII. A deep-water 
species (6-20 feet). Rather frequent, but seldom very abundant. 
Potamogeton Friesii, Rupr. V. Only in Carling wark Loch, where it 
is very plentiful. 
Potamogeton pusillus, L. “ I., II.,” IV., V., VI., VII. Frequent. The 
narrow-leaved form — var. tenuissimus, Mert. and Koch — occurs 
occasionally in rather deeper water than the type. 
Potamogeton obtusifolius, Mert. and Koch. II., V., VI., VII. Some- 
times abundant. At Barlockhart Loch a dwarf bushy form 6-8 
