| 1 | Largest perianth parts narrowly elliptic (length: width ratio c. 2-4) |
| 1' | Largest perianth parts ± ovate (length: width ratio c. 0.5-2) |
| 2 | Leaves thin, papyraceous, becoming contorted along lateral veins after drying |
| 2' | Leaves thick, coriaceous, ± flat after drying |
| 3 | Leaves large, 5.5-14.5(-19) by 2-6.5(-8.5) cm; carpels 8-14; fruit of up to 14 follicles |
| 3' | Leaves small, 3—9(—11.5) by 1.5-4(-5) cm; carpels 5-10; fruit of up to 10 follicles |
| 4 | Stamens 9-19(-20); carpels 8-14 |
| 4' | Stamens 20-33(-39); carpels 12-13 |
| 5 | Outermost perianth parts large, 4-8.5 by 4-6.5 mm; stamens 9-14(-20) |
| 5' | Outermost perianth parts small, 1.1-2.2 by 1.3-3 mm; stamens 15-19 |
| 6 | Perianth parts 8—10(—13); stamens 7 or 8; carpels invariably 8; fruit of up to 8 follicles |
| 6' | Perianth parts 10-17; stamens (5-)9-19; carpels 5-10; fruit of up to 10 follicles |
