4. Cajanus volubilis (Blanco) Blanco, Fl. Filip., ed. 2. 417. 1845.
虫豆 chong dou
Cytisus volubilis Blanco, Fl. Filip. 599. 1837; Atylosia crassa Prain ex King; A. volubilis (Blanco) Gamble; Cajanus crassus (Prain ex King) Maesen; Cantharospermum volubile (Blanco) Merrill.
Vines, twining. Stems robust, brown villous when young. Leaves pinnately 3-foliolate; stipules small, ovate, 2-3 mm, deciduous; petiole 2-8 cm; stipels linear, ca. 2 mm; petiolules extremely short; leaflets leathery, both surfaces pubescent, abaxial surface with sessile glands; terminal leaflet rhomboid to rhomboid-ovate, 2-9.5 × 2.7-9 cm, base rounded or shallowly cordate, apex obtuse; basal veins 3; lateral leaflets slightly smaller, obliquely ovate, 3.5-6 × 3-5 cm. Raceme axillary, robust, 3.5-6 cm, densely gray villous, each node with 1 or 2 flowers; bracts large, ovate, to 1.7 cm, membranous, minutely villous, deciduous; pedicels 3-7 mm, hairy. Calyx campanulate, 5-lobed; lobes triangular, unequal, upper 2 nearly connate, sparsely shortly villous. Corolla yellow, ca. 1.5 cm; standard obovate-orbicular, base auriculate at both sides; wings oblong, slightly shorter than standard; keels subequal to wings, with auricles, apex curved. Ovary pubescent; style filiform, long and curved, hairy adaxially. Legume oblong, inflated, 3-5 × 0.8-1 cm, hairy, transversely constricted between seeds. Seeds 4-6, black, usually subspherical, rarely hemispherical, 3-5 mm wide; strophiole thick and succulent. Fl. Dec-Mar, fr. Feb-Apr.
Forests. Guangxi, Hainan, Yunnan [India, Indonesia, Laos, Myanmar, Nepal, New Guinea, Philippines, Thailand, Vietnam].