Herbs, sometimes with scaly rhizomes, bulbs, bulbils or stolons, or woody perennials, shrubs, lianas or trees. Leaves penninerved, digitately or pinnately trifoliolate, imparipinnate or paripinnate, basal, alternate, subopposite or apically tufted. Stipules sometimes present. Petioles with basal joint, petiolules articulated. Inflorescences basal, axillary or pseudoterminal, cymose to pseudumbellate, rarely racemose, 1-many-flowered, bracteate and bracteolate. Flowers ♂♀, very rarely also ♂ specimens (Dapania), actinomorphic, 5-merous, hetero-tri-, -di-, or homostylous, sometimes cleistogamous. Pedicels articulate. Sepals imbricate, free or connate at base, sometimes with apical calli (Oxalis), persistent. Petals contort, quincuncial or cochlear, free but usually cohesive above the base (‘pseudosympetal’), clawed (sometimes minutely so), glabrous or inside sometimes with minute papillae or pilose. Filaments 10, obdiplostemonous, connate at base into an annulus, persistent, the epipetalous (shorter) sometimes with a basal gland near the insertion of the petals, or sometimes with 2 scales or dark lines on the annulus (Dapania), rarely without anthers; the episepalous (longer) with a dorsal tooth (Oxalis) ) or hunchbacked; anthers dorsifixed, versatile, 2-celled, dehiscing extrorsely by longitudinal slits. No disk. Ovary 5-celled, superior; styles 5, terminal, persistent, free, in LF¹ and MF erect, in SF patent to recurved, rarely reduced (♂ flowers); ovules 1-2-several per cell in 1-2 rows, epi- and anatropous, pendulous, superposed, bitegmic. Fruit capsular, loculicid, 5-celled, dry, rarely fleshy and indehiscent. Seeds usually with an aril; endosperm copious, fleshy, rarely absent; embryo straight. Distribution. 6(7?) genera with c. 850 spp. Of the Malesian representatives Oxalis, the largest genus, is most numerous in S. America and S. Africa and Biophytum in S. America and Madagascar; Dapania has 2 spp. in Malesia and 1 in Madagascar; Sarcotheca (11 spp.) is endemic in Malesia, while Averrhoa (2 spp.) assumedly also originated here; it is now cultivated pantropically.