Tree 20–30 m tall, bark grey-brown, striate or rough, slash red-brown, white underneath (fide Eggeling); young branches grey-brown, striate, puberulous, with scattered small peltate glands, denser towards the apex, older branches grey-brown, deeply striate with a gnarled appearance, frequently lenticellate. Leaves 3–5-jugate, ± 24≈18 cm, including petiole of 3–5 cm; rachis striate, puberulous, glandular when young; leaflets ovate, the median less than twice as long as broad, base subcordate and usually unequal, apex acuminate; lateral leaflets 6.5≈3–6 cm including petiolule 1–3 mm; terminal leaflet 6–8.3≈3.5–6 cm, young leaflets minutely glandular on both surfaces, mature leaflets glabrous above apart from the sometimes puberulous midrib, uniformly pubescent beneath, both surfaces with a few large scattered glands. Flowers precocious, borne singly or in 2–3-flowered inflorescences with peduncles of 1–7 mm long, either from the axils of the old leaves or cauliflorous; pedicels ± 3–3.5 cm long, striate, puberulous, sometimes glandular just below the calyx. Calyx broadly campanulate, 2–3≈2.5–3.5 cm, 3–4-lobed, chartaceous, minutely puberulous, with scattered large glands and sometimes small peltate glands toward the base; lobes elliptic to broadly elliptic, obtuse to rounded, apiculate, 1–2≈1–2 cm, margins scarious. Corolla yellow with purple veins, very broadly campanulate, 6–11≈7.5–12.5 cm, 5-lobed, the lobes broadly ovate to cordiform, overlapping, margins slightly undulate, tube 3–4 cm long; filaments 4–6.5 cm long, adnate to the corolla for up to 4 mm; thecae 6–7.5 mm long, divaricate; staminode ± 3.5 mm long, linear, slightly expanded at the apex; ovary densely tomentellous, 9–11 mm long; style 4.5–6 cm long, stigma lobes elliptic, 3–4≈3–4 mm, disk thick, cupular. Fruit not seen. Fig. 10.14–10.18, p. 41.
