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.
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