Oxalis articulata subsp. rubra
Windowbox wood-sorrel, Windowbox Wood-Sorrel
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Family: Oxalidaceae · Type: Perennial · Not Native
Oxalis articulata subsp. rubra (Windowbox wood-sorrel) is a non-native California perennial in the Oxalidaceae family, recognized by orange tubercles on sepals.
Windowbox wood-sorrel is a naturalized perennial found in coastal and southern California regions including the San Francisco Bay Area, Santa Cruz, northern Channel Islands, and Peninsular Ranges in disturbed places at elevations below 800 meters. Flowering from April to October, this plant produces white to purple-rose flowers with delicate petals and sepals featuring distinctive orange tubercles at their tips. Growing with a woody rhizome and bulb-like tubercles, it forms low-growing clusters without prominent above-ground stems. Its leaves are basal with delicate leaflets less than 2 centimeters long, arranged in a characteristic three-part pattern typical of wood-sorrel species. Small umbel-like flower clusters with up to 10 blooms emerge on peduncles longer than the leaf stems.
Identification and appearance
Key characters: 11 sympatric species; orange tubercles on sepals are diagnostic
Habitat and range
Habitat: Disturbed places
Elevation: < 800 m
California counties: San Mateo, Marin, Los Angeles, Napa, Humboldt, Mendocino, Santa Barbara, Ventura, Alameda, Stanislaus, Santa Clara, Monterey, Sacramento
Outside California: native to Brazil
Bloom period
Oxalis articulata subsp. rubra blooms Apr-Oct.
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 articulata subsp. rubra native to California?
No. Oxalis articulata subsp. rubra is not native to California (recorded as not native).
When does Oxalis articulata subsp. rubra bloom?
Oxalis articulata subsp. rubra blooms Apr-Oct.
Where in California does Oxalis articulata subsp. rubra grow?
Oxalis articulata subsp. rubra occurs in San Mateo, Marin, Los Angeles, Napa, Humboldt, Mendocino, Santa Barbara, Ventura and other counties, at elevations of < 800 m.
What plant family does Oxalis articulata subsp. rubra belong to?
Oxalis articulata subsp. rubra is in the Oxalidaceae family, genus Oxalis.
What habitat does Oxalis articulata subsp. rubra grow in?
Oxalis articulata subsp. rubra grows in Disturbed places.
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.