Juncus leiospermus var. leiospermus
Red bluff dwarf rush
Photo: parent species Juncus leiospermus · (c) Trevor Van Loon, some rights reserved (CC BY) · licence
Family: Juncaceae · Type: Grass · Native
Conservation status: CNPS 1B.1
Juncus leiospermus var. leiospermus (Red bluff dwarf rush) is a native California grass in the Juncaceae family, recognized by extremely small annual with specific vernal pool habitat.
Red bluff dwarf rush is a rare (CNPS 1B.1) California native annual found in northern California regions including northern Sierra Nevada foothills, Cascade Range, northern Sacramento Valley, and Modoc Plateau in vernal pool margins and wet chaparral woodlands at elevations of 280 to 500 meters. Flowering during spring months, this plant produces small greenish-brown flowers clustered in groups of 2 to 7 per stem. Growing with slender, delicate stems typically less than 15 centimeters tall, it forms compact clusters in seasonal wet habitats. Its narrow leaves are inconspicuous and closely clustered near the base of the plant. This diminutive rush thrives in ephemeral wetland environments, quickly completing its life cycle during the brief wet season.
Identification and appearance
Key characters: 50 sympatric species; extremely small annual with specific vernal pool habitat
Habitat and range
Habitat: Vernal pool margins, wet places in chaparral, woodland
Elevation: 280-500 m
California counties: Butte, Shasta, Tehama
Conservation status
CNPS 1B.1
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 leiospermus var. leiospermus native to California?
Yes. Juncus leiospermus var. leiospermus is native to California (recorded as native).
Where in California does Juncus leiospermus var. leiospermus grow?
Juncus leiospermus var. leiospermus occurs in Butte, Shasta, Tehama, at elevations of 280-500 m.
What plant family does Juncus leiospermus var. leiospermus belong to?
Juncus leiospermus var. leiospermus is in the Juncaceae family, genus Juncus.
Is Juncus leiospermus var. leiospermus rare or endangered?
Juncus leiospermus var. leiospermus carries California Rare Plant Rank 1B.1, state rank S2.
What habitat does Juncus leiospermus var. leiospermus grow in?
Juncus leiospermus var. leiospermus grows in Vernal pool margins, wet places in chaparral, woodland.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · CNPS Rare Plant Inventory · Index of California Plant Names · CalPhotos · CDFW CNDDB
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.