Distribution: 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
Conservation Status: Not of concern
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.