4. Oxalis corymbosa Candolle, Prodr. 1: 696. 1824.
红花酢浆草 hong hua cu jiang cao
Oxalis debilis Kunth var. corymbosa (Candolle) Lourtieg; O. martiana Zuccarini.
Perennials, (6-)10-25(-40) cm tall, stemless, pubescent. Subterranean bulb 1.5-3 cm; scales loose, papery, 3-veined; sessile bulbils 3-6 mm, numerous. Leaves basal; petiole 5-30 cm, with long sparse to moderately dense spreading white trichomes; leaflet blades obcordate, 1-4.5 × 1.5-6 cm, both surfaces covered with trichomes, adaxial surface punctate with dark calli especially near margin, apex deeply emarginate. Inflorescences corymbose cymes, irregularly branched, 8-15-flowered; peduncle 10-40 cm or longer; bracts lanceolate, membranous. Pedicels, bracts, and sepals pubescent. Pedicel 0.5-2.5 cm. Sepals lanceolate, 4-7 mm, apex with 2 reddish brown calli. Petals purplish pink with darker veins, obcordate, 1.5-2 cm. Ovary pubescent. Capsule rarely formed. Fl. Mar-Dec.
Cultivated and also escaped as a common weed of cultivated grounds and open habitats; near sea level to 2300 m. Naturalized in Anhui, Fujian, Gansu (cultivated), Guangdong, Guangxi, Guizhou, Hainan, Hebei (cultivated), Henan (cultivated), Hubei (cultivated), Hunan, Jiangsu, Jiangxi, Shandong (cultivated), Shanxi (cultivated), Sichuan, Taiwan, Xinjiang (cultivated), Yunnan, Zhejiang [native to tropical South America, cultivated as an ornamental and naturalized in warm temperate areas in many parts of the world].
Some rounded-leaved forms of Oxalis latifolia Humboldt, Bonpland & Kunth can be confused with O. corymbosa and are most clearly distinguished by the bulb scales with 5-11 veins. Both species are recorded as introduced weeds in other Asian countries. The superficially similar O. articulata Savigny is cultivated in China but is readily recognized by its woody tuberous rhizome. Specimens of O. articulata without basal parts can be distinguished by the lack of spreading hairs on the petioles and peduncles.