Herbaceous undershrub, shrub or small tree usually up to 3(–4.5) m. (or ? more) high. Branchlets glabrous, green. Leaves: petiole eglandular; rhachis glandular between all, or all but the topmost pair of leaflets. Stipules linear, very quickly falling off. Leaflets in normally 3–4 pairs (very rarely and sporadically 2 pairs by reduction, and in America as many as 5 pairs), lanceolate to ovate, almost symmetrical, (3–)4–11.3 cm. long, (1.6–)2–4 cm. wide, acutely and gradually tapering or subacuminate to apex, glabrous. Racemes axillary and apparently terminal, often aggregated near branchlet-ends. Sepals rounded at apex. Petals obovate to obovate-suborbicular, bright yellow, 1–1.5(–2) cm. long. Stamens: 2 with large anthers and long filaments; 1 with medium anther and filament; 4 with rather smaller anthers and very short filaments; 3 with usually reduced empty rounded anthers and very short filaments. Pods subterete, brown, very shortly or not beaked, slowly dehiscent, 6.2–10 cm. long, 1–1.5 cm. in diameter, longitudinally and transversely septate within. Seeds many, not embedded in pulp, olive, asymmetrically obovate, 5–6 × 3.5–4 mm.; areoles absent.
