Distribution: Widely distributed on both sides of the Cascades crest in Washington; British Columbia to California, east in Canada and northern United States to New England.
Habitat: Wet ground, ditches, shorelines, streambanks, and other riparian areas from low to moderate elevations in the mountains
Conservation Status: Not of concern
Coarse, herbaceous perennials from stout, creeping rhizomes, the stems arising singly or a few together, 6-15 dm. tall, obscurely three-sided.
Stems leafy, the leaf blades flat, grass-like, 8-15 mm. wide and up to several dm. long, the sheaths tinted with reddish-purple.
Inflorescence a compound, terminal cyme, with very numerous spikelets 4-6 mm. long, sessile in small clusters on peduncles; inflorescence subtended by several unequal, leaf-like, sheathless bracts, the largest of these 1-3 dm. long; flowers subtended by translucent, greenish-black scales about 1.5 mm. long; perianth of 4-6 slender bristles, shorter than the scale; stamens 3; style bifid.
Achenes lenticular, pale, 1.0-1.2 mm. long.