1. Stylosanthes guianensis (Aublet) Swartz, Kongl. Vetensk. Acad. Nya Handl. 10: 301. 1789.
圭亚那笔花豆 gui ya na bi hua dou
Trifolium guianense Aublet, Hist. Pl. Guiane 2: 776. 1775; Stylosanthes gracilis Kunth.
Herbs or shrublets, 60-100 cm tall, erect or rarely climbing. Stems glabrous or sparsely pubescent. Stipules sheathing, 0.4-2.5 cm. Leaves 3-foliolate; petiole short; petio-lules ca. 1 mm; leaflet blades ovate, elliptic, or lanceolate, 0.5-3(-4.5) × 0.2-1(-2) cm, glabrous, sparsely villous, or setose, base cuneate, margin sometimes sinuate, apex acute to cuspi-date. Inflorescences 1-1.5 cm, with 2-40 clustered flowers, each flower without a rudimentary axis; primary bracts 1-2.2 cm, densely long spreading setose; secondary bracts 2.5-5.5 × ca. 0.8 mm. Bracteoles 2-4.5 mm. Hypanthium 4-8 mm. Calyx tube ellipsoid to oblong, 3-5 × 1-1.5 mm. Corolla orangish yellow, with red slender striations; standard 4-8 × 3-5 mm. Legume ovoid, 2-3 × ca. 1.8 mm, glabrous or near apex pubes-cent, with 1 article, beak 0.1-0.5 mm and inflexed. Seeds grayish brown, oblate-ellipsoid, ca. 2.2 × 1.5 mm. 2n = 20.
Cultivated and naturalized in Guangdong and Taiwan [native range from Mexico to N Argentina].
This species is grown for fodder and green fertilizer and is naturalized in additional areas of SE Asia.