General:
Perennial, aquatic herb from strong rhizomes; stems mostly unbranched, often flexuous, nearly circular in cross-section, tapered, up to 200 cm long.

Leaves:
All submersed, linear-lanceolate, thin, flat, light green fading to white, 10-20 cm long, 2-4 cm wide, with 11 to 33 veins, clasping the stem, the tips rounded or hood-shaped, the stipules 3-10 cm long, fibrous or stringy; floating leaves absent.

Flowers:
Inflorescence spikelike, the spikes 3-5 cm long, with 6 to 12 whorls of flowers, the stalks inflated.

Fruits:
Achenes, widely egg-shaped or almost globe-shaped, 4.3-5.7 mm long, 3.2-4 mm wide, the beaks prominent, widely triangular, the keels wide.

Notes:
Stem anatomical characters interlacunar bundles throughout the stem aerenchyma, subepidermal bundles absent, pseudohypodermis 1 to 3 cells 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

Flower Colour:
Green

Blooming Period:
Late Spring

Fruit/Seed characteristics:
Colour: Green
Present over the Summer

Source:  The USDA

Synonyms and Alternate Names:
Potamogeton praelongus var. angustifolius Graebn.