| 1 | Leaves (pseudo-)verticillate |
| 1' | Leaves not verticillate. |
| 2 | Twigs glabrous. |
| 2' | Twigs hairy. |
| 3 | Underside of leaves hairy. |
| 3' | Underside of leaves glabrous. |
| 4 | Nerves 13-20 pairs. Leaves 21-62 cm |
| 4' | Nerves less than 15 pairs. Leaves usually much smaller. |
| 5 | Twigs thick. |
| 5' | Twigs not thick. |
| 6 | Acumen shorter than 5 mm. Fruits c. 13 mm long. Nerves 8-12 pairs. |
| 6' | Acumen longer than 5 mm. Fruits to c. 10 mm long. |
| 7 | Bracts persistent. |
| 7' | Bracts caducous. |
| 8 | Plant different |
| 8' | Inflorescence a panicle to 5 cm. Petiole 13-15 mm. Nerves 5-9 pairs. |
| 9 | Underside of leaves glabrous. |
| 9' | Underside of leaves hairy. |
| 10 | Inflorescence only 1-flowered. |
| 10' | Inflorescence more-flowered. |
| 11 | Leaves shorter than 5 cm. |
| 11' | Leaves longer than 5 cm. |
| 12 | Leaf index less than 2. Acumen shorter than 5 mm. Angle of leaf base less than 90°. Nerves less than 5 pairs. Reticulation coarse. Fruits toe. 10 mm long. Seeds not straight. Apex of leaves rounded or acute. |
| 12' | Leaf index more than 2. Acumen longer than 5 mm. Angle of leaf base more than 90°. Nerves more than 5 pairs. Reticulation fine. Fruits 17-22 mm long. Seeds straight. Apex of leaves acuminate |
| 13 | Petiole 0-5 mm. |
| 13' | Petiole more than 5 mm. |
| 14 | Seed and embryo (twice) curved |
| 14' | Seed and embryo uncinately curved towards the base. |
| 15 | Upper side of leaves hairy |
| 15' | Upper side of leaves glabrous. |
| 16 | Inflorescence only 1-flowered. |
| 16' | Inflorescence more-flowered. |
| 17 | Leaf index more than 3. Angle of leaf base less than 90°. Reticulation coarse. |
| 17' | Leaf index 2-3. Angle of leaf base more than 90°. Reticulation fine. |
| 18 | Bracts caducous. Seeds straight |
| 18' | Bracts persistent. Seeds not straight. |
| 19 | Seed and embryo (twice) curved |
| 19' | Seed and embryo uncinately curved towards the base. |
