Large trees, to 30 m high; bole rough; bark 1.2 cm thick, pale greyish-brown, transversely rugose, exfoliations irregular. Leaves compound, imparipinnate, opposite, leaflets 7-13, opposite, 4.5-13 x 2-4.5 cm, elliptic-lanceolate, elliptic-oblong, ovate or obovate, apex acuminate or caudate acuminate, base oblique, acute or obtuse, margin entire or serrate, glabrous above and puberulent beneath, chartaceous; rachis 10-21 cm long, slender, puberulent, swollen at base; petiolule 7-12 mm, slender, puberulent, grooved above; lateral nerves 6-10 pairs, pinnate, puberulent beneath, prominent; intercostae reticulate. Flowers bisexual, in terminal lax panicles. Calyx 6 mm long, campanulate, shallowly lobed, lobes 3-5, dorsal lobe much larger than the others, puberulent, tube 1.2-1.5 cm, obtuse. Corolla 2 x 1.5 cm across, yellow with red streaks, infundibuliform, pubescent inside, base glandular hairy, lobes 5, subequal, crisped. Stamens 4, didymous, divaricate; filaments unequal, smaller ones 1-1.2 cm, larger to 2.2-2.5 cm, hairy below; anthers divergent, ca. 5 mm, oblong, included, staminodes present. Ovary sessile, oblong, superior, 2-celled, syncarpous; many ovuled, 1 seriate; style slender; stigma 2, spoon shaped. Fruit a capsule, to 35 x 0.7 cm, subtetragonus, tapering at apex and base, epicarp thin, spirally splitting; seeds 8 mm long, wings obtuse at both ends.