- Vegetatively diverse with alternate or opposites leaves.
- Leaves simple , lobed, or compund.
- Without stipules; when opposite, often with inter-petiolar ridge .
- Often 3-veined with basal lateral veins arising above base.
- Stems usually soft-wooded with central pith.
- Often with rank odors and rough pubescence.
- Flowers grouped into a head that functions as a single flower.
- Fruit 1-seeded, dry and naked, usually with apical hairs or scales for wind dispersal.
Diagnosis: 1. Srubs or small trees, without stipules, leaves alternate, serrate or entire, spiraled, often palmately or 3-veined with the veins starting above the base of the blade, which extends along petiole, often lobed, or with stems grooved or ridged, some with rank unpleasant odors, rough simple hairs, tree species often with a black inner layer in trunk bark. 2. As above, but leaves simple and opposite, a few with milky latex.
Local distribution: Widespread, more common on the drier Pacific slope.
Diversity: Total: 67 genera, 146 species. Trees: 9 genera, 15 species.
Comments: Vegetatively extremely diverse; most of the tree species are small, weak-wooded trees of secondary habitats; Koanophyllon is exceptional in having hard wood and occurring in primary forest.