Trigonostemon laevigatus Mull.Arg., Flora 47 (1864)
Latin for 'glabrous'.

Synonyms
Trigonostemon anomalus Merr., Trigonostemon laevigatus var. petiolaris Airy Shaw, Trigonostemon petelotii Merr.

Description
Understorey tree up to 14 m tall and 19 cm dbh. Stipules ca. 1 mm long. Leaves alternate, simple, tripli- to penni-veined, glabrous, petiole ranging from very short to long, basal pair of secondary veins running very close to leaf margin. Flowers ca. 12 mm diameter, bright red, placed on long stalks in compressed racemes. Fruits ca. 14 mm diameter, green-bluish, on long stalk, 3-lobed, dehiscent capsules.

Ecology
In undisturbed mixed dipterocarp forest up to 600 m altitude. Usually on hillsides and ridges with sandy to clay soils. In secondary forests usually present as a pre-disturbance remnant tree.

Distribution
Andaman Islands, Indo-China, Burma, Thailand, Peninsular Malaysia, Sumatra, Borneo (Sarawak, Brunei, Sabah, South- and East-Kalimantan), Philippines.

Local names in Borneo
Jingah tulang tiga.