决明 jue ming

Cassia tora Linnaeus, Sp. Pl. 1: 376. 1753.

Herbs, suffrutescent, annual, erect, 1-2 m tall. Leaves 4-8 cm; stipules caducous, linear, 10-15 mm; petiole without glands; rachis with a club-shaped gland between leaflets; petio­lules 1.5-2 mm; leaflets 3 pairs, obovate or obovate-oblong, 2-6 × 1.5-2.5 cm, membranous, abaxially pubescent, adaxially sparsely pubescent, base cuneate to rounded and oblique, apex rounded, cuspidate. Racemes axillary, short, 1- or 2(or 3)-flow­ered; peduncles 6-10 mm; bracts linear, acute. Pedicels 1-1.5 cm. Sepals ovate or ovate-oblong, 5-8 mm, membranous, out­side pubescent. Petals yellow, unequal, obovate, lower 2 slightly longer, 12-15 × 5-7 mm, shortly clawed. Fertile sta­mens 7, nearly equal, filaments 1.5-2 mm, anthers opening by apical pores, ca. 4 mm, 3 larger, 4 smaller, staminodes absent. Ovary sessile, densely white pubescent; style glabrous. Legume terete, subtetragonous, slender, 10-15 × 0.3-0.5 cm, both ends acuminate, valves membranous. Seeds 20-30, glossy, rhom­boid, ca. 5 × 3 mm, with an areole. 2n = 26*, 28*, 56*.

Mountain slopes, wastelands, riverbank sand. Widespread to S of the Chang Jiang [native to tropical America; widely cultivated in the tropics and subtropics].

The seeds known as "jue ming zi" (决明子) are used medicinally as a diuretic and purgative.

In addition, X. Y. Zhu et al. (Legumes China, 32. 2007) recorded Senna obtusifolia (Linnaeus) H. S. Irwin & Barneby as widely culti­vated in China (as S. tora var. obtusifolia (Linnaeus) X. Y. Zhu).