Distribution: Occurring west of the Cascades crest in Washington, where nown only from Whatcom County; British Columbia to Washington, east across the northern half of North America to the Atlantic Coast.
Habitat: Wet, low ground.
Flowers: July-August
Origin: Native
Growth Duration: Perennial
Conservation Status: Not of concern
Pollination: Wind
Herbaceous perennial, without rhizomes, the culms 8-15 dm. tall, sub-terete.
Stems leafy, the leaves grass-like, elongate, flat, 2-6 mm. wide.
Inflorescence a compound, terminal cyme, with very numerous spikes 3-8 mm. long on short, slender peduncles; inflorescence subtended by several unequal, blackish-based, sheathless bracts, the largest of them nearly 1 dm. long; flowers subtended by blunt scales 1.5 mm. long, with fine red-brown lines on a pale or blackish-green background; perianth of 6 tawny, flexuous bristles that surpass the scales; stamens 3; style trifid.
Achenes triangular, pale, under 1 mm. long.
PNW Herbaria: Specimen records of Scirpus atrocinctus in the Consortium of Pacific Northwest Herbaria database
WA Flora Checklist: Scirpus atrocinctus checklist entry
OregonFlora: Scirpus atrocinctus information
E-Flora BC: Scirpus atrocinctus atlas page
CalPhotos: Scirpus atrocinctus photos