Description from Flora of China
Neustanthus peduncularis Graham ex Bentham in Miquel, Pl. Jungh. 232. 1852; Derris bonatiana Pampanini; Pueraria peduncularis var. violacea Franchet; P. yunnanensis Franchet.
Twining herbs, thinly or densely hirsute. Stipules basifixed, lanceolate, caducous; petiole 4-12 cm; stipels small, bristly; leaflets ovate or obliquely ovate, 5-12 × 3-8 cm, hirsute on both surfaces, rarely glabrous adaxially, base acute to truncate, margin entire, apex acuminate. Racemes slender, 20-40 cm. Bracts and bracteoles caducous. Flowers white, 3-5 clustered at nodes of rachis; pedicels slender, 2-6 mm. Calyx ca. 5 mm, villous; upper lobes very broad, lower ones slightly acute, shorter than tube. Standard obovate, ca. 1.4 cm, base attenuate, with narrow auricles, without callosities; wings slightly longer than keel; keel apex incurved, widened, more pale in color. Vexillary stamen broader, first adherent to others but not connate. Legumes linear, 5-8 cm × 6-8 mm, straight, valves subpapery, subglabrous or thinly pubescent. Fl. Aug, fr. Oct.
Pueraria yunnanensis was treated as a separate species by Z. F. Le and X. Y. Zhu (Ann. Bot. Fenn. 46: 419-424. 2009).
Forests. Guangxi, Guizhou, Sichuan, Xizang, Yunnan [Bangladesh, Bhutan, India, Myanmar, Nepal, Pakistan].