Description from Flora of China
Herbs, to 1 m tall. Branches terete, ribbed, appressed silky pubescent. Stipules filiform, less than 1 mm, caducous. Leaves simple; petiole 2-3 mm; leaf blade linear, 4-7 × 0.4-1 cm, both surfaces silky pilose but abaxially more densely so, midvein abaxially prominent and adaxially sulcate, secondary veins 12-15 on each side of midvein, base slightly cuneate, apex obtuse. Racemes terminal or leaf-opposed, 10-20 cm, 8-12-flowered, lax; bracts ovate-triangular, ca. 1.5 mm. Bracteoles inserted at base of calyx tube. Calyx 2-lipped, ca. 1 cm; abaxial 3 lobes linear-lanceolate, ca. 1 cm; adaxial 2 lobes lanceolate, ca. 9 mm. Corolla yellow; standard suborbicular, ca. 7 mm; keel ± as long as standard, narrowed apically from middle and extended into a long beak included in calyx. Ovary subsessile, with trichomes. Legume oblong, 2.5-3 cm, 10-20-seeded, densely brown silky pubescent. Fl. Sep-Nov, fr. Dec-Jan.
● Seashores, montane grasslands. S Hainan (Sanya).