Young branches pubescent to tomentose with appressed or ascending rusty-brown hairs, but quickly glabrescent to leave a smooth grey bark.
Leaves paripinnate: stipules 5–9 × 1–3 mm, obliquely linear-triangular, pubescent to tomentose, caducous; petiole and rachis together (4)6–11(13) cm long, of which the petiole is (0.8)1.5–2.5(3) cm, pubescent to tomentose with rusty brown hairs; petiolules 1–3 mm long; leaflets in (3)4–5(very rarely 6) pairs, strictly opposite or rarely with up to 1 mm separating members of a pair, each (3)4–7(9) × (1)1.5–2.5(4) cm, variable in shape from lanceolate (or smaller basal leaflets even ovate) to elliptic or elliptic-oblong or occasionally (particularly uppermost leaflets) oblong-lanceolate, rounded at the base (sometimes slightly asymmetric) or the uppermost pair markedly asymmetric with rounded proximal side and cuneate distal side, usually rounded at the apex (sometimes broadly so) and either apiculate or distinctly emarginate, but occasionally acute, pubescent with brownish hairs on both surfaces when young but quickly glabrescent except on the midrib beneath, sometimes with conspicuous pellucid gland-dots or dashes between the tertiary veins, often with swellings (?domatia) on the leaflet margin almost at the base on the proximal side and a few mm above the base on the distal side; lateral nerves extending to the marginal nerve.
Racemes 4–35 cm long, ± erect, brown-pubescent to -tomentose, with up to 40 flowers regularly alternately arranged on opposite sides, the rachis consequently somewhat zigzag, most flowers (except usually one or two which produce fruit) falling with pedicel to leave a prominent ledge (bract scar) at each node of the otherwise denuded rachis; bracts c.4 × 5 mm, ovate to semicircular, caducous; pedicels c.9–13 mm, with prominent bracteole scars c.1–3 mm. from the base; bracteoles 4–5 × 3–5 mm, broadly ovate to broadly elliptic, usually rounded at apex, quickly caducous.
Petals 5, 2.3–3.0(3.5) cm long, obovate-spathulate, pale mauve to bluish-purple, undulate at lower margins, villous towards midrib especially near base.
Round-topped tree usually 10–17 m high, occasionally reaching 25 m; young bark smooth and grey but becoming rough and fissured when old; deciduous.
Calyx 13–20 mm long, divided to the base into 4 lobes of which the upper (adaxial) is 7–10 mm broad, the lateral one 4–7 mm broad, and the lower (abaxial) one 3–5 mm broad and slightly the longest through curvature, all brown-pubescent to -tomentose outside except on the overlapped margins 0.5 mm broad, and pale brown-tomentose inside.
Ovary 12–15 × 4–5 mm, obliquely oblanceolate, brown-tomentose; style slightly exceeding petals and stamens; stigma capitate.
Stamens 10, about equalling the petals, one free, nine lightly fused towards the base, the lower part villous and the free part glabrous; anthers (3.5)4–5 mm long, versatile.
Seeds dark reddish brown, 2–2.5 × 1.5–1.8 × 3 mm, elliptic-orbicular, compressed.