| 1 | Erect shrubs or small trees; leaf apex mucronate; corolla lobes 3.5-5.9 mm long |
| 1' | Climbers; leaf apex not mucronate; corolla lobes 1.6-2.6 mm long |
| 2 | Pedicels with short stiff bracts; corolla tube 8.5-11.2 mm long |
| 2' | Pedicels lacking bracteoles or bracteoles only on pedicel of terminal flower; corolla tube 3-4.9 mm long |
| 3 | Inflorescence sparsely to densely puberulent; corolla tube > 4 mm long; corolla lobes > 2 mm long; ovary densely pubescent all over |
| 3' | Inflorescence glabrous; corolla tube < 4 mm long; corolla lobes < 2 mm long; ovary glabrous or pubescent only in a tuft between the carpels |
| 4 | Leaves in whorls of 3 or 4, blades 1-7 cm long; ovary glabrous |
| 4' | Leaves in whorls of 5, blades 4.5-13.1 cm long; ovary pubescent in a tuft between the carpels |
