304 NAIADACES. [Potamogeton. 
size and shape, most of them being linear or oblong rather 
than ovate. A full series may be gathered, however, show- 
ing every gradation between the form with phyllodes only 
and the plant with the typical leaves of P. natans. In the 
very swift current between the Old Weir Bridge and the 
Meeting of the Waters at Dinish Island, this form produces 
little else than phyllodes which are shorter and thicker than 
elsewhere in the Long Range ; some of the few leaves seen 
here measured 23 inches long by about } inch broad. Dr. 
Morong, Dr. Tiselius, Alfred Fryer and Arthur Bennett are 
agreed in referring P. polygonifolius var. linearis Syme to 
P. natans Linn. 
P. polygonifolius Pourr. P. oblongus Viv. 
Districts I. Il. Ill. IV. V. VI. VIL VIII. IX. 
' Native. Streams, bog pools, lakes, on wet ground, &c. 
Common. Peren. June—August. Calcifuge A. 
From sea-level, to 1,550 feet in Glas Lough on Purple 
Mountain, to 1,590 feet in Lough Googh, Reeks, and to 
2,250 feet in the Coumaknock Loughs on Brandon (2.W.S.) ; 
it ripens fruit even at the last mentioned height. : 
First record in 1875: Boswell Syme, London Bot. Exch. 
Club Report, p. 37. 
Var. CANCELLATUS Fryer. A peculiar plant growing sub- 
merged in the Long Range, Killarney, and in mountain 
streams in the south of the county, should most probably 
be referred to this variety. Mr. Arthur Bennett, to whom 
a large series was sent in 1889, seemed satisfied with the 
provisional naming “ P. polygonifolius Pourr., submerged 
form” (vide Journ. of Bot. 1890, p. 111). It differs, how- 
ever, from the ordinary submerged form of that plant, as 
Mr. Fryer points out in his Potamogetons of the British Isles, 
p. 21, in the shape and texture of the membranous leaves 
and in the rarity with which floating leaves are produced ; he 
also draws attention to the remarkable similarity of the 
Kerry plant to some forms of P. plantagineus with which he 
was formerly inclined to unite it. In Kerry P. plantagineus, 
however, is very rare indeed and appears to be confined to 
limestone areas in the extreme north, whereas this ‘‘ sub- 
merged state ” is widely scattered over the southern non- 
calcareous portion of the county, occurring in many of the 
upland streams, especially in those flowing from mountain 
lakes. Mr. Fryer gives an excellent figure of this var. in 
his Potamogetons of the British Isles, pl. 12 ; both plate and 
description exactlv matching the Kerry plant. 
