Oxalis pilosa
Hairy wood sorrel
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Family: Oxalidaceae · Type: Perennial · Native
Oxalis pilosa (Hairy wood sorrel) is a native California perennial in the Oxalidaceae family, recognized by dense spreading hairs diagnostic among natives.
Hairy wood sorrel is a California native perennial found in coastal regions including northern Coast Ranges, northern Sierra Nevada foothills, central western California, southern California coastal areas, western Transverse Ranges, and Peninsular Ranges at elevations below 1,800 meters. Flowering from February to September, this plant produces bright yellow flowers approximately 8 to 12 millimeters long with delicate, spreading petals. Growing with slender stems up to 40 centimeters tall that can root at the nodes, it has a somewhat woody taproot and dense spreading hairs covering the stems. Its leaves feature small leaflets less than 1.5 centimeters long, covered in appressed hairs and typically arranged in a delicate trifoliate pattern. The fruit is 12 to 18 millimeters long, covered with simple, short, multicellular hairs that spread outward.
Identification and appearance
Key characters: 11 sympatric species; dense spreading hairs diagnostic among natives
Habitat and range
Habitat: Coastal grassland, scrub, chaparral
Elevation: < 1800 m
California counties: Santa Barbara, Ventura, Marin, Napa, San Luis Obispo, Santa Cruz, San Diego, Riverside, San Francisco, Santa Clara, Sacramento, Los Angeles, Sonoma, Alameda, Humboldt, San Mateo, Monterey
Outside California: to British Columbia, Mexico
Bloom period
Oxalis pilosa blooms Feb-Sep.
How to tell it apart
vs Trifolium: Oxalis has heart-notched leaflet tips; clover has oval or elongate leaflet tips without notches.; vs Medicago: Oxalis leaflets fold at night and have notched tips; medick leaflets don't fold and have toothed edges.; vs Marsilea: Oxalis is a land plant with flowers; water clover is aquatic with spore-bearing structures.; vs Pelargonium: Oxalis is soft-stemmed with 3 leaflets; geranium is woody-based with palmately lobed leaves.; vs Bowlesia: Oxalis has clover-like leaves with 3 leaflets; Bowlesia has kidney-shaped undivided leaves.
Frequently asked questions
Is Oxalis pilosa native to California?
Yes. Oxalis pilosa is native to California (recorded as native).
When does Oxalis pilosa bloom?
Oxalis pilosa blooms Feb-Sep.
Where in California does Oxalis pilosa grow?
Oxalis pilosa occurs in Santa Barbara, Ventura, Marin, Napa, San Luis Obispo, Santa Cruz, San Diego, Riverside and other counties, at elevations of < 1800 m.
What plant family does Oxalis pilosa belong to?
Oxalis pilosa is in the Oxalidaceae family, genus Oxalis.
What habitat does Oxalis pilosa grow in?
Oxalis pilosa grows in Coastal grassland, scrub, chaparral.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · Index of California Plant Names · CalPhotos
Last updated 2026-09-30
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.