3. Oxalis Linnaeus, Sp. Pl. 1: 433. 1753.
酢浆草属 cu jiang cao shu
Herbs, annual or perennial, usually with tubers, bulbs, or rhizomes. Stems erect, creeping, or absent (rosette). Stipules usually absent or very small. Leaves radical or alternate, 3-foliolate (Chinese taxa). Inflorescences solitary, cymose, or umbellate; peduncle long, with 2 small bracts at apex, bracts appearing to be mid peduncle in solitary-flowered species. Sepals distinct, imbricate. Petals yellow, red, pink, or white, convolute, sometimes basally slightly connate. Stamens all fertile; filaments basally connate or distinct. Ovary locules with 1 to several ovules. Capsule loculicidally dehiscent. Seeds with an outer fleshy coat which bursts elastically.
About 700 species: tropics and subtropics of both hemispheres but extending into temperate regions; eight species (two introduced) in China.
Oxalis bowiei Aiton ex G. Don, which is native to South Africa, is cultivated as an ornamental in China and is often persistent as a greenhouse weed.
Oxalis bulbifera X. S. Shen & H. Sun was described from a single collection in Anhui (Tiantangzhai), Shen Xian-sheng 20088 (holotype, KUN). The type specimen could not be traced in KUN, and no further material was available on contacting the authors. Although described as having affinities with Oxalis acetosella, it differs in several peculiar characteristics: the flowers are solitary or in pairs and the aerial stem is well developed. Even more unusual is the development at the leafless stem apex of "bracts" with bulbils in the axils. These are probably more accurately termed stipules, but the bulbils are a mystery. It is impossible to interpret this very unusual finding without recourse to herbarium material, and as such it is not included in the main account.
