Juncus bryoides
Moss rush, Moss Rush
(c) Matt Berger, some rights reserved (CC BY) · licence
Family: Juncaceae · Type: Grass · Native
Juncus bryoides (Moss rush) is a native California grass in the Juncaceae family, recognized by . Key features: tiny size, hair-like stems, single flower per stem.
Moss rush is a California native annual found in the Sierra Nevada, Cascade Range, southern Coast Ranges, Transverse Ranges, Peninsular Ranges, and northeastern Sierra Nevada in wet meadows, washes, and granitic seeps at elevations of 600 to 3,600 meters. This diminutive plant forms dense, reddish-brown tufts with delicate hair-like stems less than 0.2 millimeters wide, growing to just 2.2 centimeters tall. Growing in compact clusters with very short stems, it produces tiny flowers with 4 to 8 shiny perianth parts that curve over the small fruit. Its leaves are basal, typically one-quarter to equal the stem length, with no sheath appendages. The plant produces minimal reproductive structures, with flowers occurring singly on stems and seeds measuring just 0.3 to 0.5 millimeters long.
Identification and appearance
Key characters: 52 sympatric species. Key features: tiny size, hair-like stems, single flower per stem
Habitat and range
Habitat: Common. Wet places, washes, meadows, granitic seeps
Elevation: 600-3600 m
California counties: Inyo, Riverside, San Diego, Fresno, Kern, Mono, Monterey, San Bernardino, Madera, Tulare, Lassen, Tuolumne, Santa Barbara, Sierra, Plumas, El Dorado
Outside California: to Oregon, Idaho, Colorado, Baja California
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 bryoides native to California?
Yes. Juncus bryoides is native to California (recorded as native).
Where in California does Juncus bryoides grow?
Juncus bryoides occurs in Inyo, Riverside, San Diego, Fresno, Kern, Mono, Monterey, San Bernardino and other counties, at elevations of 600-3600 m.
What plant family does Juncus bryoides belong to?
Juncus bryoides is in the Juncaceae family, genus Juncus.
What habitat does Juncus bryoides grow in?
Juncus bryoides grows in Common. Wet places, washes, meadows, granitic seeps.
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.