KEY TO THE FORMS

1Twigs at apex 3-4 mm diameter, with rusty red hairs 0.5 mm long. Anthers 10-12. Leaves coriaceous. — E Borneo.
1'Twigs at apex 4-6 mm diameter, with either pale brown hairs 0.5 mm long, or hairs chocolate or dark brown, 1-2 mm long. Anthers 11-15. Leaves chartaceous to coriaceous.
2Leaves chartaceous. Twig apex with pale brown or yellowish brown hairs 0.3-1 mm long. Anthers 11-14. — Sarawak, Brunei, Sabah, Nunukan Is.
2'Leaves coriaceous [the venation on the lower surface indistinct]. Twig apex with chocolate or dark brown hairs 1-2 mm long. Anthers 15. [Flowers with hairs 1 mm long.] — Brunei, Sarawak.