Equisetum hyemale subsp. affine
Common scouring rush, Common Scouring Rush
hebdromadaires on Flickr (via Wikimedia Commons) · CC BY-SA
Family: Equisetaceae · Type: Herb · Native
Equisetum hyemale subsp. affine (Common scouring rush) is a native California herb in the Equisetaceae family, recognized by double dark bands on sheaths and scabrous texture.
Common scouring rush is a California native perennial found in coastal, northern, central, and southern California regions including the North Coast, Klamath Ranges, Sacramento Valley, Central Western California, and desert areas, occurring in streams, moist sandy, and gravelly areas at elevations below 2,500 meters. Unlike many horsetails, this species lacks branches and grows as a single, distinctively textured green stem reaching 60 to 210 centimeters tall. Its stems are scabrous (rough-textured) with pronounced sheaths 7 to 17 millimeters long, featuring two distinctive dark bands at the base and tip, and bearing 22 to 50 small teeth that generally fall away. The plant has a distinctive cylindrical, jointed structure typical of horsetails, with each segment featuring a characteristic ring-like appearance and a dark-banded sheath. Reproducing through spores rather than flowers, this ancient plant species produces green, spherical spores in cone-like structures with pointed tips.
Identification and appearance
Key characters: 5 sympatric species; distinguished by double dark bands on sheaths and scabrous texture
Habitat and range
Habitat: Streams, moist, sandy, gravelly areas
Elevation: < 2500 m
California counties: Ventura, Sonoma, Los Angeles, Riverside, San Bernardino, Imperial, Sacramento, El Dorado, San Diego, Santa Cruz, Humboldt, San Luis Obispo, Santa Barbara, Fresno, Shasta, San Francisco, Kern, Monterey, Alameda, Tulare, Mendocino, Mariposa, Plumas, Siskiyou, Trinity, Lassen, Yuba, Marin, Inyo, Santa Clara, Sierra, Lake, Contra Costa, Placer, Del Norte, Tuolumne, Mono, Butte, Nevada, San Mateo, Modoc, Merced, Alpine, Tehama, Glenn, Napa, Stanislaus, Amador, Orange, Yolo, San Joaquin, Solano
Outside California: North America, Mexico, Guatemala
How to tell it apart
vs Foeniculum: Equisetum has scale-like leaves in whorls; Fennel has feathery, thread-like leaf divisions.; vs Hippuris: Equisetum has fused scale-like leaves at joints; Hippuris has separate linear leaves in whorls.; vs Juncus: Equisetum stems have distinct joints with leaf whorls; Juncus stems are smooth without joints.; vs Elegia: Equisetum stems are rough and hollow with whorled scales; Elegia has smooth stems with overlapping leaf sheaths.; vs Pinus: Equisetum is an herbaceous plant with jointed stems; Pine is a woody tree with needle clusters.
Frequently asked questions
Is Equisetum hyemale subsp. affine native to California?
Yes. Equisetum hyemale subsp. affine is native to California (recorded as native).
Where in California does Equisetum hyemale subsp. affine grow?
Equisetum hyemale subsp. affine occurs in Ventura, Sonoma, Los Angeles, Riverside, San Bernardino, Imperial, Sacramento, El Dorado and other counties, at elevations of < 2500 m.
What plant family does Equisetum hyemale subsp. affine belong to?
Equisetum hyemale subsp. affine is in the Equisetaceae family, genus Equisetum.
What habitat does Equisetum hyemale subsp. affine grow in?
Equisetum hyemale subsp. affine grows in Streams, moist, sandy, gravelly areas.
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.