4. Canavalia cathartica Thouars, J. Bot. Agric. 1: 81. 1813.
小刀豆 xiao dao dou
Canavalia ensiformis (Linnaeus) Candolle var. turgida (Graham ex A. Gray) Baker; C. microcarpa (Candolle) Piper; C. turgida Graham ex A. Gray; Lablab microcarpus Candolle.
Herbs, biennial, robust, twining. Stems and branches sparsely pubescent. Leaflets ovate, 6-10 × 4-9 cm, sparsely white pubescent on both surfaces, base broadly cuneate, truncate, or rounded, apex acute or rounded. Racemes with 1-3 flowers at each node of rachis. Calyx ca. 12 mm, pubescent, upper lip with rounded lobes, shorter than tube, lower lip with 3 teeth. Corolla pink or purplish, 2-2.5 cm; standard orbicular, ca. 2 × 2.5 cm, with 2 thickenings near base, clawed, apex emarginate; wings and keel curved, ca. 2 cm. Legumes oblong, 7-9 × 3.5-4.5 cm, turgid, apex rostrate. Seeds brownish black, elliptic, ca. 18 × 12 mm, hard and smooth; hilum 10-14 mm. Fl. and fr. Apr-Oct.
Seashores, riverbanks. Guangdong, Hainan, Taiwan [widely distributed in tropical Asia and some areas of Africa and Australia].