1 | Stipules caducous. Seeds 6 or fewer. |
1' | Stipules long-persistent. Ovules and seeds 9. |
2 | Primary veins curving approximately parallel towards the margin at distances of 1-2 cm; secondary venation scalariform. |
2' | Primary veins few, independently curved towards the margin, secondary venation irregular. |
3 | Inflorescences fasciculate (rarely stalked in R. anguifera). |
3' | Inflorescences on a peduncle (if racemose, see R. longiracemosa). |
4 | Dorsal appendage of the anthers small. Style hairy. Fruit enveloped in moss-like appendages. |
4' | Dorsal appendage of the anthers distinct. Style glabrous. Fruit smooth. |
5 | Anthers with small ventral appendages. Ovules 3. Fruit subglobose, with 3 seeds. |
5' | Anthers with ventral appendages about as long as the dorsal one. Ovules 6. Fruit conical, subtended by the expanded calyx, with 1 seed. |
6 | Gynoecium glabrous. Petals to 4 mm long. Anthers with small dorsal appendage. Fruit triangular with rounded corners, 1-3 cm long, valves thick. |
6' | Gynoecium hairy. Petals to 9 mm long. |
7 | Pedicels jointed near the base. Anthers with small dorsal appendage. Fruit subglobose to ovoid, 8-11 mm long, hairy, with a hairy style remnant. |
7' | Pedicels jointed about the middle. Anthers with a dorsal appendage 1-2 times as long as the cells. (Fruit unknown.). |
8 | Inflorescences more or less elongate. Anthers with distinct ventral appendages. Fruit 1¼-4 cm ø. |
8' | Inflorescences fasciculate, or flowers densely set on a short rachis. Anthers with small or no ventral appendages. Fruit 0.5-1½ cm ø. |
9 | Stipules 1-3½ mm long. Inflorescence axis ½-2½ cm long. Leaves often obovate. |
9' | Stipules (2-)4-21 mm long. Inflorescence axis to c. 10 cm long. Anthers often bearded at the base. |
10 | Leaves petiolate, more or less concolorous. Anthers with a dorsal appendage about as long as the cells or longer. |
10' | Leaves subsessile, discolorous, pale underneath, 3½-6cm long. Anthers with a small dorsal appendage. Style hairy in the middle only. Ovary glabrous. Andamans, India? |
11 | Leaves 1-7(-14) cm long. Petiole 1-5 mm. Plant dioecious; in the ♂ flowers only a style, in the ♀ flowers the anther cells vestigial, ovules 6. |
11' | Leaves 6-36 cm long. Petiole 5-35 mm. Flowers bisexual. Ovules 3. |
12 | Stipules 1½-6 mm, scarcely striate. Leaves dark-coloured in the dried state. Fruit sparsely hairy. |
12' | Stipules 4-16 mm, distinctly striate. Leaves greenish in the dried state. Fruit glabrous. |