酸豆 suan dou

Trees, 10-15(-25) m tall. Trunk 30-50(-90) cm d.b.h. Bark dark ashy, irregularly longitudinally splitting. Leaflets ob­long, small, 1.3-2.8 cm × 5-9 mm, glabrous, base obliquely rounded, apex rounded or emarginate. Flowers few, yellowish tinged with purplish red stripes; peduncles and pedicels yel­lowish green puberulent; bracteoles 2, ca. 1 cm, enclosing flow­er bud before anthesis. Calyx tube ca. 7 mm; lobes lanceolate-oblong, ca. 1.2 cm, reflexed after anthesis. Petals obovate, sub­equal to calyx lobes, margin repand, curled. Stamens 1.2-1.5 cm, pubescent near base, free parts of filaments ca. 7 mm; an­thers elliptic, ca. 2.5 mm. Ovary slightly incurved, terete, ca. 8 mm, hairy. Legume brownish, straight or arcuate, terete-oblong, turgid, 5-14 cm, often irregularly constricted. Seeds 3-14, brownish, shiny. Fl. May-Aug, fr. Dec-May. 2n = 24, 26, 28*.

Cultivated. Fujian, Guangdong, Guangxi, ?Hainan, Yunnan (Jinsha Jiang valley) [native to Africa; widely cultivated in the tropics].

The pulp of the fruit and the seed oil are edible. The fruit can be used medicinally for relieving fever and constipation and as an antiscor­butic. The hard, heavy wood is used for building houses and making farm tools and furniture. The trunk is robust, with wind-resistant strength, and is suitable for planting on seashores.