Juncus exiguus
Klamath or weak rush, Weak Rush
Family: Juncaceae · Type: Perennial · Native
Juncus exiguus (Klamath or weak rush) is a native California perennial in the Juncaceae family, recognized by montane habitat, smooth stems, and distinctive sheath coloration.
Klamath rush is a California native perennial found in the Klamath Ranges, northern Coast Ranges, Cascade Ranges, and Sierra Nevada Mountains in montane wet meadows, springs, and shores at elevations of 700 to 2,300 meters. While flowering details are not specified, the plant has dark brown stems up to 71 centimeters tall with narrow ridges and solid pith. Growing with slender stems less than 1.6 millimeters wide, it features dark brown to red-brown leaf sheaths that are shiny below and gradually converge at narrow, symmetrical summits. Its leaves have thin margins often minutely blackened and slightly rolled at the tips, with overlapping sheaths extending halfway from the base. The fruit is small, about 1.6 to 1.9 millimeters long, with three internal chambers and truncated ends.
Identification and appearance
Key characters: 53 sympatric species; key features are montane habitat, smooth stems, and distinctive sheath coloration
Habitat and range
Habitat: Montane, wet meadows, springs, shores
Elevation: 700-2300 m
California counties: Shasta, Fresno, Glenn, Mariposa, Tehama, Trinity, Kern, Sierra, Placer, Amador, El Dorado, Butte, Sutter, Yuba, Nevada, Plumas, Humboldt, Tulare, Tuolumne, Del Norte, Siskiyou, Madera, Mendocino
Outside California: Oregon
How to tell it apart
vs Schoenoplectus: Juncus has leaf blades present; Schoenoplectus is leafless with only bladeless sheaths at base.; vs Carex: Juncus has round or flattened stems; Carex has triangular stems you can feel.; vs Luzula: Run finger along leaf edge - smooth = Juncus, hairy = Luzula.; vs Elegia: Juncus has small individual flowers; Elegia has showy papery bracts and branching structure.; vs Cyperus: Juncus has round stems and capsules; Cyperus has triangular stems and lens-shaped achenes.
Frequently asked questions
Is Juncus exiguus native to California?
Yes. Juncus exiguus is native to California (recorded as native).
Where in California does Juncus exiguus grow?
Juncus exiguus occurs in Shasta, Fresno, Glenn, Mariposa, Tehama, Trinity, Kern, Sierra and other counties, at elevations of 700-2300 m.
What plant family does Juncus exiguus belong to?
Juncus exiguus is in the Juncaceae family, genus Juncus.
What habitat does Juncus exiguus grow in?
Juncus exiguus grows in Montane, wet meadows, springs, shores.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · Index of California Plant Names · CalPhotos
Last updated 2026-09-30
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.