Medium or large tree up to 30 m. high; crown flattened; bark smooth, very rarely rough, grey. Young branchlets finely and shortly brownish-pubescent, soon glabrescent and usually deep or blackish-purple, ultimately grey-barked. Leaves: pinnae (Fig. 22/1, p. 163) 5–7(–8) pairs (rarely only 3 on occasional reduced leaves), each pinna more or less narrowing upwards; leaflets of 2 distal pairs of pinnae 9–16(–17 fide I.T.U., ed. 2) pairs, obliquely rhombic-quadrate to rhombic-subfalcate, mostly about 10–20(–25) mm. long, 4–8(–13) mm. wide, auricled or sometimes not on proximal side, obtuse to acute at apex, subglabrous or somewhat pubescent on midrib and margins, rarely, especially when young, some occasional hairs on the primary lateral nerves; raised venation beneath lax. Stipules and bracts at base of peduncles lanceolate, up to about 6–7 mm. long and 2–2.5 mm. wide. Peduncles puberulous or finely pubescent; bracteoles mostly caducous, linear, inconspicuous, (1–)2–6 mm. long, normally shorter than the flower-buds except when extremely young. Flowers subsessile; pedicels puberulous or sometimes glabrous, 0.25–0.75(–1) mm. long. Calyx 2.5–5 (very rarely indeed 1.5–2) mm. long, minutely, shortly, and rather appressedly brownish-pubescent to subglabrous outside. Corolla 6.5–12 mm. long, minutely pubescent outside, white. Staminal tube exserted about 1.5–2.8 cm. beyond corolla, white below, crimson above. Pod oblong, flat or slightly transversely plicate, (8–)10–21 cm. long, 2–3.4 cm. wide (to 4 cm. wide, fide I.T.U. ed. 2), glabrescent, glossy, eglandular, less prominently and closely venose than in A. adianthifolia, pale brown to reddish-brown or purplish. Seeds 9–12 mm. long, 10 mm. wide, flattened.
