23. Oxalis purpurea Linnaeus, Sp. Pl. 1: 433. 1753.
Purple wood-sorrel Purple wood-sorrel
Oxalis variabilis Jacquin
Herbs perennial, acaulous, rhizomes present, <slender, sparsely scaly>, stolons absent, bulb solitary, <1–2.5 cm>, or with clustered bulblets; bulb scales <black, thickened>, not prominently nerved. Leaves basal, <rarely absent at flowering>; petiole (1.5–)3–5 cm; leaflets 3, green to deep purple abaxially, green adaxially, broadly obovate to obtriangular or broadly rounded-rhombic, 10–20 mm, not lobed, <apex truncate to rounded or obtuse, rarely slightly emarginate, margins and> abaxial surface hairy, adaxial surface glabrous, oxalate deposits absent. Inflorescences 1-flowered; scapes 1.5–6(–8) cm, sparsely to moderately villous, <hairs eglandular>. Flowers tristylous; sepal apices without tubercles; petals yellow basally, usually purple to red, pink, salmon, or white, rarely yellow, distally, 25–35 mm. Capsules not seen.
Flowering Feb–Apr. Waste places, especially near gardens; 20–100 m; introduced; Calif.; s Africa; introduced also in Europe, Australia.
Oxalis purpurea is widely cultivated as an ornamental because of its large, solitary flowers in many color forms, borne on short scapes barely higher than the level of the leaves. Plants of O. purpurea apparently do not produce fertile fruit in California, where it is naturalized in scattered central and southern coastal counties.