Distribution: Widely dsitributed on both sides of the Cascades crest in Washington; British Columbia to California, east across North America to the Atlantic Coast.

Habitat: Slow-moving rivers and streams, lakes, ponds, and backwater channels, generally at low elevations.

Flowers: June-August

Origin: Introduced from Eurasia

Growth Duration: Perennial

Conservation Status: Not of concern

Pollination: Wind

Aquatic, herbaceous perennials from slender rhizomes, the stems branching, somewhat flattened, 4-8 dm. long and 1-2 mm. broad.

: Leaves alternate, all submersed, narrowly oblong, 3-8 cm. long and 3-10 mm. broad, strongly crisped, finely serrulate on the upper margins, rounded at the tip, sessile and clasping, 3- to 5-nerved; stipules delicate, 4-8 mm. long.

Flowers perfect, in spikes 1-2 cm. long on peduncles 3-5 cm. long; perianth of 4 clawed segments, each with an upturned, oval blade; stamens 4, fused with the claws; pistils 4, sessile.

Achenes ovoid, 3 mm. long, with 3 obtuse but prominent keels, tapered into a beak 2-3 mm. long.

One hybrid, Potamogeton crispus × P. praelongus (= P. ×undulatus Wolfgang ex Schultes & Schultes f.), has been described.