Juncus effusus
Soft or lamp rush, Soft Or Lamp Rush
(c) Douglas Goldman, some rights reserved (CC BY-SA) · licence
Family: Juncaceae · Type: Grass · Native
Juncus effusus (Soft or lamp rush) is a native California grass in the Juncaceae family.
Soft rush is a California native perennial found in various bioregions in wet meadows, marshes, and streambanks at low to moderate elevations. Flowering from May to September, this rush produces small pale brown flowers in dense clusters with numerous individual blooms. Growing with stout rhizomes and smooth, shiny stems 60 to 155 centimeters tall, it forms dense tufted clusters in wetland environments. Its stems are notably cylindrical and leafless, with a distinctive smooth and glossy upper surface that rises vertically from a thick base 2 to 5 millimeters wide. The tiny seeds have a minute appendage and are approximately 0.5 millimeters long, contributing to the plant's delicate reproductive strategy.
Identification and appearance
Key characters: 0 sympatric species; geographically isolated
Habitat and range
California counties: San Francisco, Fresno, Monterey, Placer, San Bernardino, Sonoma, Los Angeles, Riverside, Santa Barbara, Sacramento, Kern, San Joaquin, San Diego, El Dorado, Nevada, Calaveras, Trinity, Marin, Santa Cruz, Kings, Contra Costa, Lake, Mendocino, Tuolumne, San Luis Obispo, Humboldt, San Benito, Butte, San Mateo, Amador, Mariposa, Santa Clara, Napa, Alameda, Yuba, Ventura
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 effusus native to California?
Yes. Juncus effusus is native to California (recorded as native).
Where in California does Juncus effusus grow?
Juncus effusus occurs in San Francisco, Fresno, Monterey, Placer, San Bernardino, Sonoma, Los Angeles, Riverside and other counties.
What plant family does Juncus effusus belong to?
Juncus effusus is in the Juncaceae family, genus Juncus.
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.