Alstonia iwahigensis Elmer, Leafl. Philipp. Bot. 4 (1912)
(Latin for 'From the river Iwahig', a river on the island Palawan in the Philippines)

Description
Emergent tree up to 66 m tall and 109 cm dbh. Stem with copious white latex. Stipules absent. Leaves in whorls, simple, penni-veined. Flower ca. 6 mm in diameter, white, with narrow corolla tube, placed in layered dense flower clusters. Fruits ca. 340 mm long, green-brown, dry, dehiscent, paired follicles, filled with many small hairy seeds which are wind dispersed.

Ecology
In undisturbed and disturbed (logged and burned) forests up to 800 m altitude. Usually in mixed dipterocarp forest, but also found on the edge of peat swamp and in swamp forest. Usually on sandy soils, but also on clay, loam and ultrabsaic soils. Growing on alluvial sites, but more often on hillsides and ridges.

Uses
The latex mixed in honey is used as a tonic.

Distribution
Borneo (Sarawak, Brunei; Sabah, Central-, East- and South-Kalimantan) and the Philippines.

Local names in Borneo
Pelantan; Pulai; Pulai basung; Pulai gunung; Pulantan; Selutong; Tambirag; Tomboilik.