Juncus uncialis
Inch-high rush
(c) Kyle Elshoff, some rights reserved (CC BY) · licence
Family: Juncaceae · Type: Grass · Native
Juncus uncialis (Inch-high rush) is a native California grass in the Juncaceae family, recognized by tiny size, single flower per stem, and truncated bract diagnostic.
Inch-high rush is a California native annual found in northern California Interior, Cascade Range Foothills, central Sierra Nevada Foothill, Central Valley, southern Coast Ranges, and southern California coastal areas in vernal pool margins and other drying places at elevations of 45 to 1,700 meters. Extremely small, this rush grows to just 0.3 to 3.5 centimeters tall with pale stems less than half a millimeter wide. Dense and tufted, the plant produces tiny flowers with 4 to 6 perianth parts, typically with sepals slightly larger than petals. Its basal leaves are short, measuring less than three-quarters the height of the stem, with no sheath appendages. The fruit is ovoid or elliptic, roughly the same length as the perianth, containing 2 to 4 chambers.
Identification and appearance
Key characters: 52 sympatric species; tiny size, single flower per stem, and truncated bract diagnostic
Habitat and range
Habitat: Uncommon. Vernal pool margins, other drying places
Elevation: 45-1700 m
California counties: Lake, Madera, Shasta, Tehama, Solano, Butte, Fresno, Sacramento, Merced, Sutter, Placer, Yuba, Lassen, Stanislaus, San Luis Obispo, Tuolumne, Calaveras, Mariposa, Santa Barbara, Monterey, San Diego, Plumas, Yolo
Outside California: to Washington, Nevada
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 uncialis native to California?
Yes. Juncus uncialis is native to California (recorded as native).
Where in California does Juncus uncialis grow?
Juncus uncialis occurs in Lake, Madera, Shasta, Tehama, Solano, Butte, Fresno, Sacramento and other counties, at elevations of 45-1700 m.
What plant family does Juncus uncialis belong to?
Juncus uncialis is in the Juncaceae family, genus Juncus.
What habitat does Juncus uncialis grow in?
Juncus uncialis grows in Uncommon. Vernal pool margins, other drying places.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · Index of California Plant Names · CalPhotos
Last updated 2026-10-07
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.