| 1 | Leaves simple (not unifoliolate) |
| 1' | Leaves compound; imparipinnate, trifoliolate, or unifoliolate. |
| 2 | Leaflets with glabrous pit-like domatia in the axils between nerves and midrib on the lower surface; apex caudate to Ungulate. |
| 2' | Leaflets without glabrous pit-like domatia in the axils between nerves and midrib on the lower surface; apex acute, acuminate, or obtuse. |
| 3 | Leaflets 13-24 by 5-7½ cm. Branchlets conspicuously lenticellate |
| 3' | Leaflets smaller, 4-10 by l¼-3¾ cm. Branchlets rather smooth. |
| 4 | Leaves (l-)5(-7)-foliolate, terminal petiolule (½-)1¾-2½ cm. Anthers c. 1 mm long. (Pollen grains rather smooth) |
| 4' | Leaves unifoliolate and/or trifoliolate, terminal petiolule very short, c. 1/5 cm. Anthers c. ½ mm long. (Pollen grains conspicuously reticulate) |
| 5 | Leaflets crenate-dentate. Petals sparsely pilose on the inner surface. Fruits densely puberulous |
| 5' | Leaflets entire (very rarely some of them irregularly dentate in R. lamprocarpd). Petals glabrous (except in R. taitensis). Fruits glabrous. |
| 6 | Inflorescences terminal, sometimes also with some axillary ones in the leaf axils at the end of twigs, very rarely axillary only. Petals sparsely pilose on the inner surface. Fruits black when ripe |
| 6' | Inflorescences axillary and/or pseudoterminal (then terminal bud of the twig present). Petals glabrous. Fruits not black when ripe. |
| 7 | Old leaflets pubescent on both surfaces (without a group of reddish brown papillae or glands in the axils between nerves and midrib on the lower surface). Ovary sparsely hairy |
| 7' | Old leaflets almost glabrous on both surfaces. Ovary glabrous. |
| 8 | Petals 1-1½ by ⅔ mm. Leaflets usually with a spot consisting of a group of reddish brown papillae or glands in the axils of the nerves beneath. Small tree or shrub. |
| 8' | Petals 2-3 by 1¼-1½ mm. Leaflets rarely with papillae or glands as above. Scandent shrub or liana, sometimes small shrub or tree |
