Page authors: Don Knoke, David Giblin
Juncus interior
inland rush

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

Habitat: Gravel or sand riverbanks, oxbow marshes, canals, and ditches.

Flowers: May-July

Origin: Native

Growth Duration: Perennial

Conservation Status: Not of concern

Pollination: Wind


Tufted perennial with densely branching rhizomes, the stems 1-10, 2-6 dm. tall.


Leaves 1-2, basal, the blades flat, 5-15 cm. long and 0.5-1.1 mm. broad; leaf bases sheathing, the sheaths with whitish or purplish auricles 0.2-0.4 mm. long.


Inflorescence somewhat compact, 1.5-7 cm. long, the involucral bract shorter than the inflorescence; perianth 3.3-4.4 mm. long, the 6 segments greenish, lanceolate-acuminate; stamens 6.


Capsule ellipsoid to nearly globose, 3.8-4.7 mm. long, light to dark tan.

Accepted Name:
Juncus interior Wiegand
Publication: Bulletin of the Torrey Botanical Club. 27: 516. 1900.

Synonyms & Misapplications:
Juncus interior Wiegand var. interior [KZ99]
Juncus tenuis Willd. var. arizonicus (Wiegand) F.J. Herm. [KZ99]
Juncus tenuis Willd. var. neomexicanus (Wiegand) F.J. Herm. [KZ99]
Additional Resources:

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

WA Flora Checklist: Juncus interior checklist entry

OregonFlora: Juncus interior information

E-Flora BC: Juncus interior atlas page

CalPhotos: Juncus interior photos

11 photographs:
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