A tree that grows to a height of 12–24m with a girth of 1.2–1.6m. Bole is 6m tall. Bark is smooth and grayish. Inner bark is yellow, and shows an abundant milky latex. Sapwood is pale orange. Leaves are simple, sessile, whorled, and exstipulate. Blade is spathulate and thick, 6.5cm × 2.7cm – 5cm × 2.3cm, and shows about 24 pairs of secondary nerves crowded, at right angles to the midrib. Inflorescences are loose, few flowered, and the pedicels are up to 1.3cm long. Flowers are salver-shaped, 5-lobed, the lobes contorted, 7mm – 1.2cm long. Fruits are pairs of green–blue, with 13.5cm × 2mm follicles.

As febrifuge and vermifuge (bark)

PROSEA (Plant Resources of South-East Asia) Foundation

Applied externally to sores and diseased skin (plant latex); to lower fever and to expel worms from the intestines (bark); for diabetes mellitus (bark extract)

Christophe Wiart. Medicinal Plants of Asia and the Pacific, P:250-251, CRC Press, June 2006.