6. Rhynchosia viscosa (Roth) Candolle, Prodr. 2: 387. 1825.
粘鹿藿 nian lu huo
Glycine viscosa Roth, Nov. Pl. Sp. 349. 1821.
Herbs. Stems twining, robust and slightly woody, densely gray viscous pubescent and with sticky glandular hairs. Leaves pinnately 3-foliolate; stipules small, usually lanceolate, 5-8 mm, pubescent, always persistent; petiole 4-9 cm, densely pubescent and with sticky glandular hairs; petiolules 1.6-2.5 cm; leaflets papery; terminal leaflet broadly elliptic or rhomboid-elliptic, 5-8 × 3.5-5 cm, both surfaces villous, abaxial surface with dense small yellow-brown sessile glands, basal veins 3, lateral veins 3-5 pairs, base rounded, apex usually acute, caudate-acuminate; lateral leaflets obliquely ovate to obliquely elliptic. Racemes solitary or a few clustered in axil, 7-22 cm; peduncle 2.8-3.9 cm, densely villous and glandular hairy. Calyx ca. 8 mm, exterior with glands; upper lobes triangular. Corolla ca. 2 × as long as calyx. Legume oblong, ca. 2 × 1 cm, pubescent, straight, apex with small beak, narrowed to both ends. Seeds 2, black, reniform, ca. 5 × 4 mm. 2n = 22.
Roadsides. Yunnan [India, Indonesia, Malaysia, Nepal, Sri Lanka, Thailand; Africa (widespread), Madagascar].
The Chinese material belongs to Rhynchosia viscosa var. viscosa. Verdcourt (Kew Bull. 25: 82-86. 1971) recognized three further varieties, all almost entirely restricted to Africa.