A woody climber that grows to a length of 10m. Stems are terete, 3mm in diameter, lenticelled, and exude a white latex after incision. Leaves are simple, opposite, and exstipulate; petiole is 1.5–5cm long; blade is cordate and lanceolate, 11cm × 4.3cm – 11cm × 5.5cm, and shows 8–9 pairs of secondary nerves and a few tertiary ones. Inflorescences are 4.4cm-long cymes which have 15–30 flowers; flower pedicels are a peduncle, 5mm – 1.5cm long; calyx is 7mm long and puberulent; sepals are oblong–lanceolate and puberulent; corolla is yellowish-green to red; corolla tube is about 1cm long, puberulent outside, pilose or glabrous with a pilose throat inside. Fruits are pairs of follicles which are 7–13cm × 2–3.5cm, glabrous, somewhat obtusely 4-angled, and contain several hairy seeds.

1,8-cineole, acetaldehyde, acetic acid, alpha-pinene, alpha-terpineol, benzyl benzoate, beta-pinene, ethanol, ethyl acetate, geraniol, geranyl acetate, neral, nerol, nerolidol, terpinen-4-ol (flowers)

Used internally to promote urination (plant); to treat conjunctivitis (flowers)

Christophe Wiart. Medicinal Plants of Asia and the Pacific, P:267, CRC Press, June 2006.