Page author: Kevin Armitano
Schoenoplectus americanus
Olney's three-square bulrush

Origin: Native

Conservation Status: Not of concern


Perennial herbs ranging from 0.4-2.5 m; rhizome long, 2-5 mm diameter; stems 3-10 mm diameter, sides 3, deep-concave, edges sharp, faces smooth.


Generally all basal, whorled or 3-ranked; blades number 1-3, 2-8 mm wide, 3-sided toward tip, occasionally flat, smooth, or margin minute-scabrous; sheath closed, long, not splitting; ligule glabrous.


Inflorescence head-like; inflorescence bract generally erect, 1-6 cm; spikelets ovate, not flat, many-flowered, numbering 2-20, 5-15 x 3-5 mm; flower bract spiraled, 3-4 mm, tip notch 0.1-0.4 mm, awn 0.2-0.6 mm, often sparse-scabrous; perianth bristles (2)5-6(7), somewhat straight, generally brown, reflexed-barbed or hirsute; stamens generally 3; style 1, thread-like, base not enlarged, stigmas 2-3.


Generally obovate, brown, mucronate, 1.8-2.8 x 1.3-2 mm, 2- or obscure-3-sided, smooth.

Accepted Name:
Schoenoplectus americanus (Pers.) Volkart ex Schinz & R. Keller
Publication: Fl. Schweiz ed. 2. 1: 75. 1905. 1905.

Synonyms & Misapplications:
Scirpus americanus Pers. [HC]
Scirpus olneyi A. Gray [HC]
Additional Resources:

PNW Herbaria: Specimen records of Schoenoplectus americanus in the Consortium of Pacific Northwest Herbaria database.

WA Flora Checklist: Schoenoplectus americanus checklist entry.

E-Flora BC: Schoenoplectus americanus atlas page.

CalPhotos: Schoenoplectus americanus photos.

USDA Plants: Schoenoplectus americanus information.

3 photographs:
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