1. Cassia fistula Linnaeus, Sp. Pl. 1: 377. 1753.
腊肠树 la chang shu
Trees, deciduous, to 15 m tall. Leaves 30-40 cm, with 3 or 4 pairs of leaflets; leaflets adaxially shiny, broadly ovate or ovate-oblong, 8-13 × 4-8 cm, leathery, both surfaces puberulent when young, glabrous when mature, base broadly cuneate, apex acute. Racemes axillary, 20-40(-60) cm, lax, pendent, many flowered; flowers 3.5-4 cm in diam. Pedicels 3-5 cm, slender. Sepals narrowly ovate, 1-1.5 cm, reflexed at anthesis. Petals golden yellow, broadly ovate, subequal, 2.5-3.5 cm, shortly clawed. Stamens 10, 3 long with curved filaments 3-4 cm, anthers ca. 5 mm, exceeding petals, 4 short with straight filaments 6-10 mm, reduced stamens with minute anthers. Ovary stalked, strigulose; stigma small. Legume pendulous, blackish brown, terete, sausage-shaped, indehiscent, 30-60 cm, 2-2.5 cm in diam. Seeds numerous, separated by papery septa, glossy brown, elliptic, flattened. 2n = 28.
Cultivated in S and SW China [native to India; cultivated throughout the tropics].
This is a common ornamental tree in the southern region. The bark contains tannin, a source of red dye. The fruit pulp and seeds are used medicinally as a laxative. The wood is hard and durable and is used for props, bridges, and farm tools.