| 1 | Corolla tube < 10 mm long; calyx 3-6 mm long |
| 1' | Corolla tube > 10 mm long; calyx 5.5-17 mm long |
| 2 | Corolla tube 18-65 mm long, 2.4-7.9 times as long as calyx; calyx colleters glabrous or sparsely pubescent inside |
| 2' | Corolla tube 12-23 mm long, 1.1-1.4 times as long as calyx; calyx colleters densely pubescent inside |
