[ 1822 ]
POTAMOGETON natans.
Broacl-leaved Pond-weed.
TETRANDRIA Tetragynia.
G en. Char. Cal. none. Petals A. Style none. Seeds 4 .
S pec. Char. Upper leaves oblong-ovate, on footstalks,
floating ; lower linear. Flower stalks cylindrical.
S y n . Potamogeton natans. Linn. Sp. PL 1 8 2 . Sm.
FI. B rit. 193. Huds. 74-. With. 211. H ull. 39 .
Relh. 63. S ik h . 6 4 . Abbot. 37- FI. Dan. 1 .1025.
P . rotundifolium. Ila ii Syn. 148.
C o m m o n in pools and slow rivers, covering the surface of
the water all summer with broad floating leaves, and decorating
it in July with innumerable pale upright spikes of
flowers, raised 2 or 3 inches above its level.
The roots are long, perennial, creeping in the mud. Stems
much branched, several feet in length, round, leafy. «Lower
leaves far beneath the surface, membranous, linear and very
narrow: upper ones numerous, all floating on the top, 2
inches or more in length, coriaceous, oval-oblong, many-
, ribbed, on long stalks. Stipulas large, lanceolate, concave,
acute. Flower-stalks solitary, axillary, (with a bractea like
the stipulas,) thick, nearly cylindrical, being merely contracted
just under the spike; and not swelling upwards before
that contraction, as in P . heterophyllum, t. 1235. Flowers
dull green, with copious whitish pollen.
This is the largest British Pond-weed, and the most commonly
noticed. It can be confounded with none but heterophyllum,,
which we have already explained to be sufficiently
distinct.