Erect herb to 1.3 m tall, arising from a perennial tuberous or woody rootstock. Stems annual, angled, sometimes ribbed, sparsely to densely white or golden pilose, young stems pale green becoming dark grey. Leaves pinnately 3-foliolate; leaflets narrowly elliptic, elliptic or ovate, pubescent on both surfaces, reddish-black gland-dotted on the upper surface (×10 magnification), with black glands on the leaflet lower surface, hence the upper surface is paler; terminal leaflet 2–7.3 × 1.1–4 cm, lateral leaflets 1.6–6.6 × 0.8–3.2 cm; petiole 0.5–6.2 cm long; rhachis 0.5–2.5 cm long; petiolules 2–5 mm long; stipules 6–12 × 2–4 mm, lanceolate, pubescent, striate, usually caducous; stipels 2 mm long. Inflorescences consisting of short, lax axillary pseudoracemes, sometimes aggregated into axillary and terminal congested panicles; peduncle of the pseudoraceme 4–22 mm long; rhachis of the pseudoraceme 3–50 mm long; peduncle of the panicle 4–12 mm long; rhachis of the panicle 5–55 mm long; pedicels 1–6(8) mm long, white pilose; bracts absent; bracteoles minute, caducous. Calyx pilose with gold coloured or white hairs; tube 3 mm long; lobes minute, 1–1.5 mm long, upper pair fused along most of their length. Standard purple, sometimes tinged greenish or yellowish outside with deep purple veining inside, 5–9 × 5–8 mm, almost round; wings and keel pale green or yellow, tinged with purple. Ovary 4 mm long, linear-oblong, compressed, white pilose; style 3 mm long; stigma minute, terminal, capitate, penicillate. Pods 1.5–3.1 × 0.6–1.6 cm, narrowly oblong, falcate, densely golden pilose, 4–5-seeded. Seeds reddish-brown speckled black, 4 × 3 × 2 mm; aril narrowly elliptic, creamy-white.
