Page authors: Don Knoke, David Giblin
Scirpus cyperinus
cotton-grass bulrush

Distribution: Ocurring chiefly west of the Cascades crest in Washington; southwestern British Columbia to California, east to Idaho and Montana; native from central North America to the Atlantic Coast.

Habitat: Wet areas and riparian zones at low elevations.

Flowers: July-August

Origin: Introduced from eastern North America

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.

Accepted Name:
Scirpus cyperinus (L.) Kunth
Publication: Enum. Pl. 2: 170. 1837. 1837.

Synonyms & Misapplications:
Eriophorum cyperinum L.
Scirpus cyperinus (L.) Kunth var. andrewsii (Fernald) Fernald
Scirpus cyperinus (L.) Kunth var. pelius Fernald
Scirpus rubricosus Fernald
Additional Resources:

PNW Herbaria: Specimen records of Scirpus cyperinus in the Consortium of Pacific Northwest Herbaria database

WA Flora Checklist: Scirpus cyperinus checklist entry

OregonFlora: Scirpus cyperinus information

E-Flora BC: Scirpus cyperinus atlas page

CalPhotos: Scirpus cyperinus photos

25 photographs:
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