Asia-Temperate: China: China - Guangxi, - Guizhou, - Hebei, - Henan, - Hubei, - Shaanxi, - Yunnan
Lianas, to 25 m. Stems twined leftward, white villous when young, soon glabrescent. Leaves 7-13-foliolate; rachis 15-25 cm, including petiole 3-5 cm; leaflet blades elliptic-ovate to lanceolate-ovate, 5-8 × 2-4 cm with basal pair smallest and becoming larger apically, both surfaces appressed pubescent when young but glabrescent, base rounded to cuneate and somewhat asymmetric, apex attenuate to caudate. Racemes terminal or axillary from branchlets of previous year, 15-30 × 8-10 cm, white villous. Pedicel 2-3 cm, slender. Flowers 2-2.5 cm, fragrant. Calyx with adaxial tooth longer than others. Corolla purple or occasionally white; standard orbicular, sometimes retuse, glabrous, apex truncate. Ovary tomentose, with 6-8 ovules. Legume oblanceolate, 10-15 × 1.5-2 cm, tomentose, hanging on branches persistently. Seeds 1-3 per legume, brown, thickly lenticular, ca. 1.5 cm in diam., shiny. Fl. Apr-May, fr. May-Aug. 2n = 16.
'Jako' is noted for it's highly fragrant white flowers. The primary difference between 'Jako' and the parent species is flower color.