1 | Corolla infundibuliform; stamens completely included in the corolla tube |
1' | Corolla rotate, salverform or somewhat infundibuliform; stamens clearly exserted from the corolla tube |
2 | Flowers pendulous; corona absent |
2' | Flowers pendulous or not; corona present |
3 | Corona with antipetalous lobes divided more than half way to base giving the whole corona a fimbriate look |
3' | Corona with antipetalous lobes entire or divided less than half way to base |
4 | Antipetalous corona lobes deeply divided or at least strongly dentate |
4' | Antipetalous corona lobes entire or at most weakly crenate |
5 | Gynoecium syncarpous; fruits solitary. — Philippines |
5' | Gynoecium apocarpous but united into a single style; fruits paired. — Widespread |
6 | Corolla tube 3.8-4 mm long; stamens inserted in the upper half of the corolla tube |
6' | Corolla tube 1.8-2.8 mm long; stamens inserted in the lower half or around the middle of the corolla tube |
7 | Corolla tube 3.7-10 mm long, 1.7-5.5 times as long as sepals. — Philippines |
7' | Corolla tube c. 3.5 mm long, c. 1.6-1.9 times as long as sepals. — New Britain |