Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east to Montana and Colorado; Minnesota to Maine, south to Virginia in eastern United States.

Habitat: Quiet water, mostly in lakes.

Flowers: August - September

Origin: Native

Growth Duration: Perennial

Conservation Status: Not of concern

Pollination: Wind

Aquatic, herbaceous perennials from slender rhizomes, the stems terete, stout, branching, 1-4 dm. long.

Leaves alternate, submersed, linear-lanceolate, up to 12 cm. long, mostly 3-4 mm. broad, acute, finely serrulate, with a broad mid-nerve and 20-35 very fine lateral nerves, stiffly 2-ranked and crowded on the stem; stipules fused to the leaf bases for 10-15 mm., the free portion longer, white.

Stem freely-branching in the inflorescence, with many peduncles 3-5 cm. long; flowers perfect, in spikes 7-20 mm. long on the peduncles; perianth of 4 clawed segments, each with an upturned, oval blade; stamens 4, fused with the claws; pistils 4, sessile.

Achenes obovoid, 3.5-4 mm. long, with a sharp dorsal keel and rounded lateral keels, and without a beak.