| 1 | Leaves peltate |
| 1' | Leaves not peltate |
| 2 | Leaf-base cordate or broadly rounded, domatia absent. Mature cupule of fruit 3-8 cm long, margin of orifice 2- (or -3-)toothed |
| 2' | Leaf-base acute or rounded, domatia present. Mature cupule of fruit 2.5-3 cm long, margin of orifice entire |
