Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to Mexico; east over most of the United States to the Atlantic Coast.

Habitat: Shallow to rather deep water.

Flowers: June-August

Origin: Native

Growth Duration: Perennial

Conservation Status: Not of concern

Pollination: Wind

Aquatic, herbaceous perennials from slender rhizomes, the stems sub-terete, sparingly branched, up to 2 m. long.

Leaves alternate, the submersed leaves with petioles 2-10 cm. long, the blades lanceolate-elliptic, 10-20 cm. long and 1-2 cm. broad, thin; floating leaves leathery, long-petiolate, elliptic, 5-12 cm long and 2-4 cm. broad; stipules 4-8 cm. long.

Flowers perfect, in densely-flowered spikes with up to 15 whorles, 2-6 cm. long; peduncles thicker than the stems; perianth of 4 clawed segments, each with an upturned, oval blade; stamens 4, fused with the claws; pistils 4, sessile.

Achenes obovoid, 3-4 mm. long, with a sharp dorsal keel and prominent lateral keels.