2. Oxalis stricta Linnaeus, Sp. Pl. 1: 435. 1753.
直酢浆草 zhi cu jiang cao
Acetosella chinensis (Haworth ex G. Don) Kuntze; A. fontana (Bunge) Kuntze; Oxalis chinensis Haworth ex G. Don; O. corniculata var. stricta (Linnaeus) C. C. Huang & L. R. Xu; O. cymosa Small; O. diffusa Boreau; O. europaea Jordon; O. fontana Bunge; O. repens Thunberg var. stricta Hatusima; O. shinanoensis T. Itô ; Xanthoxalis cymosa (Small) Small; X. europaea (Jordan) Moldenke; X. stricta (Linnaeus) Small.
Annuals or short-lived perennials, all vegetative parts (except petioles) variably pubescent with simple and multiseptate hairs. Stems to 30 cm, usually single when young, erect, branching and finally decumbent with age but not rooting at nodes; underground stolons usually present. Stipules absent or rounded and inconspicuous. Leaves alternate or sometimes almost opposite or whorled; petiole (2-)3-8(-12) cm, pubescent with simple and at least some septate trichomes at base; leaflet blades obcordate, (0.3-)0.8-1.8(-2.5) × (0.3-)1.2-3(-3.5) cm, green, abaxially sparsely pubescent, adaxially glabrous, apex deeply emarginate. Inflorescences dichotomous cymes, sometimes umbellate, 2-5(-7)-flowered; peduncle ca. 2 × as long as petioles or longer, base with a swollen articulation; bracts linear, 1.5-2 × ca. 1 mm, glabrous or with very sparse trichomes. Pedicels (3-)5-10 mm, erect in fruit, pubescent with simple and septate hairs. Sepals linear to narrowly elliptic, 4-7 × 1-2 mm, margin ciliate. Petals pale yellow, oblong-obovate, 5-10 × 2-3 mm. Capsule cylindric, 8-15 × 2-3.5 mm, 5-sided, glabrous or pubescent with only septate trichomes. Seeds 4-10 per locule, brown to brownish red, ovoid-oblong, 1-1.5 × 0.8-1 mm, transversely ridged. Fl. and fr. Feb-Oct. 2n = 24.
Forests, ravines; 400-1500 m. Guangxi, Hebei, Henan, Hubei, Jiangxi, Jilin, Liaoning, Shanxi, Zhejiang [Japan, Korea, SE Russia; E North America, introduced in Europe].
Oxalis stricta is similar in appearance to O. corniculata, and some recorded occurrence of O. stricta in China beyond those reported here represent misidentification.