General:
Perennial, aquatic herb from strong rhizomes; stems up to 200 cm long, usually branched.

Leaves:
Submersed leaves elliptical to widely lanceolate, thin, flat, intense yellow-green, 8-20 cm long, 2-5 cm wide, with 7 to 19 veins, the tips sharp-pointed, tapering into long stalks at the bases, the stalks less than 2 cm long, the stipules 2.5-8 cm long; floating leaves often absent, if present elliptical, 5-20 cm long, 2-7 cm wide, leathery, long-stalked, the tips pointed, tapering at the bases.

Flowers:
Inflorescence spikelike, the spikes with 8 to 15 whorls of flowers, the stalks thick, inflated.

Fruits:
Achenes, widely egg-shaped or almost globe-shaped, 2.5-3.6 mm long, 2.1-3 mm wide, the beaks widely triangular, the keels wide.

Notes:
Stem anatomical characters Interlacunar bundles strongly developed in 1 circle, often with few additional bundles in neighbouring circles, subepidermal bundles usually absent, pseudohypodermis absent or 1 cell thick, endodermis of U-cells.

Source:  The Illustrated Flora of British Columbia

If more than one illustration is available for a species (e.g., separate illustrations were provided for two subspecies) then links to the separate images will be provided below. Note that individual subspecies or varietal illustrations are not always available.

Illustration Source:  The Illustrated Flora of British Columbia

Synonyms and Alternate Names:
Potamogeton angustifolius Bercht. & C. Presl
Potamogeton heterophyllus Schreb.
Potamogeton lucens auct. non L.