四棱豆属 si leng dou shu

Authors: Delin Wu & Mats Thulin

Botor Adanson.

Herbs, climbing or prostrate, rarely erect, with tubers. Leaves pinnately 3-foliolate; stipules produced below point of insertion; leaflets stipellate. Flowers solitary or in axillary racemes with swollen nodes. Bracts small, very caducous; bracteoles larger, mem­branous, persistent for a time. Calyx 5-toothed, 2 upper teeth connate into entire or bifid lip. Corolla lilac or violet, exserted from calyx; standard suborbicular, appendaged with basal auricles; wings obliquely obovate; keel incurved at apex, obtuse. Vexillary sta­men free at base, connate with tube in middle; anthers uniform, 5 basifixed alternating with 5 dorsifixed. Ovary shortly stipitate; ovules 3-21; style incurved; stigma globose, densely penicillate-villous. Legumes oblong, 4-winged lengthwise, septate between seeds. Seeds ovate or oblong-elliptic, with or without aril.

About 10 species: distributed in tropical regions of the Old World; one species (introduced) in China.

Lower Taxon

• Psophocarpus tetragonolobus (Linnaeus) Candolle