| 1 | Anthers strongly curved or hooked; the calyx limb short, irregular, usually infolded; leaf lamina to 12 cm long, mostly acuminate and acute |
| 1' | Anthers slightly curved or straight; the calyx limb more than 1 mm long, membranous |
| 2 | Leaf lamina to 10 cm long, not acuminate; corolla 30-35 mm long; ovary constricted below the spreading calyx limb |
| 2' | Leaf lamina to 30 cm long, acuminate; corolla 40-65 mm long; ovary not constricted below the erect calyx limb |
