9. Crotalaria trichotoma Bojer, Ann. Sci. Nat., Bot., sér. 2. 4: 265. 1835.
光萼猪屎豆 guang e zhu shi dou
Crotalaria usaramoensis E. G. Baker; C. zanzibarica Bentham.
Herbs or shrublets, to 2 m tall. Branches terete, ribbed, pubescent. Stipules subulate, ca. 1 mm. Leaves 3-foliolate; petiole 3-5 cm; petiolules ca. 2 mm; leaflet blades narrowly elliptic, 6-10 × 1-2(-3) cm, abaxially pubescent, adaxially glabrous, base cuneate, apex acuminate and mucronate. Racemes terminal, ca. 20 cm, 10-20-flowered; bracts linear, 2-3 mm. Pedicel 3-6 mm; bracteoles inserted on apical half of pedicel, similar to bracts in shape but shorter. Calyx subcampanulate, 4-5 mm, 5-lobed; lobes triangular, ± as long as tube, glabrous to sparsely pubescent. Corolla yellow, exserted beyond calyx; standard orbicular, ca. 1.2 cm in diam., base with 2 appendages, apex awned; wings oblong, ± as long as standard; keel ca. 1.5 cm, slightly rounded, narrowed apically from middle, marginally pubescent at base, beak rather long. Ovary subsessile. Legume cylindric, 3-4 × 0.7-1.2 cm, 50-70-seeded, glabrescent; style and calyx persistent. Seeds orangish buff to terra-cotta-colored, reniform, smooth. Fl. Apr-Aug, fr. Sep-Dec.
Grasslands, along trails; 100-2000 m. Cultivated or naturalized in Fujian, Guangdong, Guangxi, Hainan, Hunan, Sichuan, Taiwan, and Yunnan [native to E Africa; introduced in Australia, Indonesia, Malaysia, Philippines, Sri Lanka, and Vietnam].