刀豆 dao dou

Dolichos gladiatus Jacquin, Collectanea 2: 276. 1788; Canavalia ensiformis (Linnaeus) Candolle var. gladiata (Jac­quin) Kuntze; C. gladiolata Sauer.

Herbs, climbing, several meters tall. Leaflets ovate, 8-20 × 8-12 cm, sparsely whitish or brown pubescent on both sur­faces, base rounded or cuneate, apex acuminate. Racemes 10-20-flowered; peduncles 20-25 cm. Flowers 2 or 3 clustered at each node. Calyx 15-16 mm, slightly pubescent, upper lip rounded, lower lip with 3 acute teeth. Corolla white or pink, 3-3.5 cm; petals clawed and auriculate; standard broadly elliptic, 3-3.5 × ca. 2.5 cm, emarginate; wings and keel ob­long, incurved, smaller than standard. Legumes linear-oblong, slightly curved, 20-35 × 3.5-6 cm, thickly leathery, each valve with extra rib ca. 5 mm from sutural rib. Seeds reddish brown, elliptic-oblong, ca. 3.5 × 2 cm; hilum ca. 1.5 cm. Fl. Jul-Sep, fr. Oct.

Widely cultivated in areas S of the Chang Jiang [domesticated in Asia; widely cultivated in the tropics].

Originally cultivated in E Asia and now widely cultivated in the tropics, this plant is not known out of cultivation, except as an escape.

The legumes and seeds are edible. It is also grown as a green ma­nure and forage.