Distribution: Newfoundland south to Florida, occasionally west across southern Canada to southeast British Columbia and northern Washington.
Habitat: Wet, low ground.
Flowers: July-August
Origin: Introduced
Conservation Status: Not of concern
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 cyperinus in the Consortium of Pacific Northwest Herbaria database.
WA Flora Checklist: Scirpus cyperinus checklist entry.
E-Flora BC: Scirpus cyperinus atlas page.
CalPhotos: Scirpus cyperinus photos.
USDA Plants: Scirpus cyperinus information.