Potamogeton.| NAIADACE A. 307 
P. nitens Weber. 
Districts — — — IV. V. VI ~ ~— ~ 
Native. Lakes and running water. Very rare but locall 
abundant. Peren. June—August. 
IV. Abundant in the upper portion of the River Laune 
from its exit near the Lower Lake, Killarney, to near tidal 
influence: R.W.S. 1890, &c., and in 1904.—V. In a large 
lake between Castlegregory and the sea, plentifully 
(Moore) Journ. of Bot., 1864, p. 326—still there in 1907; 
and—VI. In several places in the Lower Lake, Killarney, as 
in the old mine-holes on Ross Island, along the Cahernane 
shore, in Castlelough Bay, along the Muckross shore, &c. : 
R.W.S. 1888, and in 1909. Abundant in the River Laune 
from its exit near the lake to near tidal influence, 1889-1909 : 
RWS. 
First record in 1864: Moore, Journ. of Bot., p. 326. 
In Kerry this species includes a number of very dissimilar 
forms. The still-water plant from the Lower Lake, 
Killarney, differs, however, but slightly from that gathered 
in Castlegregory Lake, the Killarney plant approaching 
nearer to type nitens than that from Castlegregory, which 
is usually the var. curvirotius Hartm. The River Laune, 
on the other hand, is a regular storehouse of puzzling forms, 
which differ very widely in appearance. 
Mr. Fryer who examined a large series of these forms, 
both fresh and dried, had no hesitation in placing them 
under nitens as an aggregate, and as he regards P. nitens 
Weber as a series of hybrids—P. graminifolius x perfoliatus, 
P. heterophyllus x perfolatus and P. Zizit x perfoliatus, 
his views receive additional confirmation from these Laune 
plants, in the well known tendency to variation in hybrids, 
as well as from the presence in the river of P. graminifolius 
and P. perfoliatus in great abundance. It may be noted 
also that while these hybrid forms flower freely there, they 
very rarely ripen fruit. One very interesting form which 
grows abundantly in the upper portion of the river near the 
lake, shows the influence of P. perfoliatus, amongst which it 
grows, in a marked degree ; it has the short stout flowering 
spikes of this plant, while the leaves on some of the specimens 
examined measured 3 inches long by 14 inches broad. It 
was formerly named P. nitens Weber var. LATIFOLIUS T's., 
by Mr. Ar. Bennett, while Mr. Fryer referred it to P. nitens 
forma PRELONGIFOLIA Tis. ; it has finally found a resting 
place as P. nitens var, Maximus Ar. Benn.—vide Journ. of 
Bot. 1907, p. 173. 
