Tall tree, 18–40 m. high; bark usually reddish-brown and scaly (but said on Sangster 538 to be “grey, fairly smooth”); young branchlets glabrous. Leaves: rhachis with petiole 9–32 cm. long; leaflets (4–)5–7(–8, fide F.C.B.) pairs, petiolulate, oblong to oblong-elliptic, 5–13(–20, fide F.C.B.) cm. long, 2.6–5.8(–7, fide F.C.B.) cm. wide, ± apiculate or shortly acuminate at apex. Inflorescence paniculate. Flowers sweetly scented, with hypanthium 1.5–4.5 cm. long. Sepals densely tomentellous outside, outer 2 elliptic, 1–1.7 cm. long, 0.8–1.5 cm. wide, inner 2 obovate-elliptic, 1.4–2 cm. long, 0.9–1.6 cm. wide. Petal upwardly turned, 3.5–6 cm. long, with a long red-purple claw, and a crumpled ± bilobed lamina 3–5 cm. wide which is white at first and then turns pink. Stamens 7 fertile, with pubescent filaments, red like the style; staminodes 2, elongate, 0.5–2 cm. long. Style very sparingly pubescent. Pods curved-reniform, (8–)11–19.5 cm. long and 5.5–8 cm. wide (fide F.C.B.). Seeds black, ovoid-ellipsoid, 2.5–3.3(–4.5, fide F.C.B.) cm. long, 1–1.7(–2, fide F.C.B.) cm. wide, with a deeply bilobed orange aril, one at least of whose lobes reaches to about the middle or near the top of the seed.