Juncus gerardi subsp. gerardi
Mud rush, Mud Rush
Daderot (via Wikimedia Commons) · CC0
Family: Juncaceae · Type: Perennial · Not Native
Juncus gerardi subsp. gerardi (Mud rush) is a non-native California perennial in the Juncaceae family, recognized by salt marsh habitat, black-striped hooded perianth, and creeping habit.
Mud rush is a naturalized perennial found in the Contra Costa and Solano counties coastal salt marshes at elevations below 10 meters. Flowering from late spring to summer, this plant produces small black-striped flowers with hooded, incurved tips. Growing with a creeping rhizome and reaching 15 to 45 centimeters tall, it forms loose clusters of slender stems. Its generally basal leaves are flat with blunt sheath appendages measuring 0.4 to 0.7 millimeters long. The fruit is approximately ellipsoid and roughly equal in length to the perianth parts.
Identification and appearance
Key characters: 25 sympatric species; key features are salt marsh habitat, black-striped hooded perianth, and creeping habit
Habitat and range
Habitat: Coastal salt marsh
Elevation: < 10 m
California counties: Contra Costa, Solano, Alameda
Outside California: Oregon to southern British Columbia, eastern North America, Eurasia, northern Africa
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 gerardi subsp. gerardi native to California?
No. Juncus gerardi subsp. gerardi is not native to California (recorded as not native).
Where in California does Juncus gerardi subsp. gerardi grow?
Juncus gerardi subsp. gerardi occurs in Contra Costa, Solano, Alameda, at elevations of < 10 m.
What plant family does Juncus gerardi subsp. gerardi belong to?
Juncus gerardi subsp. gerardi is in the Juncaceae family, genus Juncus.
What habitat does Juncus gerardi subsp. gerardi grow in?
Juncus gerardi subsp. gerardi grows in Coastal salt marsh.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · Index of California Plant Names · CalPhotos
Last updated 2026-10-06
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.