Triglochin. | NAIADACEA. 303 
NAIADACESX. 
TRIGLOCHIN Linn. 
T. palustre Linn. Arrow-grass (genus). 
Districts I. II. IU. IV. V. VI. VIL. VIII. Ix. 
Native. Marshes and wet pastures, &c. Rather common. 
Peren. June—August. 
From sea-level, to 1,350 feet near the Priestsleap road 
(R.W.S.). 
First record in 1890: Stewart, Proc. R.I.A. 
T. maritimum Linn. 
Districts I. II. I. — V. — VIL VII. Ix. 
Native. Salt marshes and muddy sea-shores. Common 
and locally abundant. Peren. June—August. 
First record in 1890: Stewart, Proc. RIA. 
POTAMOGETON Linn. 
P. natans Linn. Pondweed (genus). 
Districts I. II. III. IV. V. VI. VII. VIII. IX. 
Native. Lakes, ponds, ditches, streams, &c. Common. 
Peren. June—August. 
From sea-level, to 1,100 feet in Lough Callee, Hag’s Glen, 
Reeks, to 1,280 feet in Lough Barrot east of Connor Hill 
(Hart.), and to 1,450 feet in Lough Ferta, Teermoyle 
Mountain, Glenbeigh (R.W.S.). 
First record in 1882: Hart, Proc. R.I.A. 
In the Long Range, Killarney, P. natans occurs in a very 
puzzling form which was referred by Boswell Syme to 
P. polygonifolius var. linearis (vide London Bot. Exch. Club 
Report, 1875, p. 37). This plant was first gathered in the 
above locality by Mr. A. G. More ; it grows there in great 
abundance in water several feet in depth, and is kept by 
the current which is fairly swift in places, almost constantly 
submerged. The broad floating leaves of P. natans are 
consequently seldom produced and the flowering spikes even 
more rarely, while the whole plant is much drawn out and 
branched, the lower phyllodes, sometimes attaining 15 or 16 
inches in length with the diameter of a coarse thread. _ When 
present, the floating leaves vary in number on different 
plants from one to many ; they also differ greatly in their 
