Tree to c. 30 m high. Shoots with prominent white lenticels, glabrous. Buds black, large. Petioles to c. 8 cm long. Leaflets usually 9-13, sessile, 4.5-10 × 1.75-3.5 cm, lanceolate, glabrous except for midrib and main veins beneath, serrate or serrulate; base cuneate; apex acuminate. Fls numerous in dense clusters. Calyx and corolla 0. Filaments > anthers. Anthers ovoid, often apiculate, dark purple. Samara (2.7)-3-4 cm × 7-9 mm, narrow-elliptic, oblanceolate or elliptic-obovate; wing extending c. 1/2 way along seed. Seed 1.2-1.5 cm long, compressed.