Shrub or tree to c. 10 m high, glabrous; branches sparsely or rarely densely tuberculate, viscid. Leaves alternate, scattered, linear-lanceolate to elliptic, mostly 3–9 cm long, 3–14 mm wide, often falcate, apex acute to acuminate, uncinate, margins dentate in upper half, entire in lower half; petiolate. Inflorescences 4–11-flowered; pedicels 4–6 mm long, glabrous, viscid. Sepals triangular, 0.5–1 mm long, acute, valvate, glabrous, viscid; corolla 3.5–16 mm long, glabrous outside, inside of lobes and upper part of tube villous, white, often tinged purplish-pink, spotted or unspotted; stamens exserted; ovary and style glabrous. Fruit ovate, 4–5.5 mm long, 3–3.5 mm wide, compressed, acute.