Page authors: Don Knoke, David Giblin
Juncus acuminatus
knotty leaf rush, sharp-fruited rush, tapered rush

Distribution: Occurring chiefly west of the Cascades crest in Washington; British Columbia to California, east across much of North America to the Atlantic Coast.

Habitat: Ditches, lake margins, meadows and other wet places.

Flowers: May-August

Origin: Native

Growth Duration: Perennial

Conservation Status: Not of concern

Pollination: Wind


Tufted perennial without rhizomes, the stems 4-8 dm. tall.


Leaves alternate, semi-terete, hollow, with prominent partitions; leaf bases sheathing, the margins of the sheaths free at the tip, forming rounded auricles.


Inflorescence terminal, 5-12 cm. long, longer than the involucral bract, with 5-20 heads, the heads 5-8 mm. broad and 10- to 20-flowered; perianth tawny or greenish-brown, 3-3.5 mm. long, the 6 segments subequal, lanceolate-acuminate; stamens 3; style 1 mm. long.


Capsule equal to the perianth, narrowly ovoid, 3-angled, tapered to the tip.

Accepted Name:
Juncus acuminatus Michx.
Publication: Flora Boreali-Americana. 1: 192. 1803.

Synonyms & Misapplications:
Juncus acuminatus Michx. var. legitimus Engelm.
Juncus pallescens E. Mey. ex Buchenau
Juncus pondii A.W. Wood
Additional Resources:

PNW Herbaria: Specimen records of Juncus acuminatus in the Consortium of Pacific Northwest Herbaria database.

WA Flora Checklist: Juncus acuminatus checklist entry.

OregonFlora: Juncus acuminatus information.

E-Flora BC: Juncus acuminatus atlas page.

CalPhotos: Juncus acuminatus photos.

USDA Plants: Juncus acuminatus information.

27 photographs:
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