| 1 | Leaves bifoliolate on flowering shoots; fertile stamens 10 |
| 1' | Leaves entire or bilobed on flowering shoots; fertile stamens 3, rarely 2 |
| 2 | Anthers opening by a central pore |
| 2' | Anthers opening by a slit lengthwise |
| 3 | Nectariferous disc present |
| 3' | Nectariferous disc absent |
| 4 | Flowers pseudopapilionaceous; fleshy, digitate body present on the rim of hypanthium |
| 4' | Flowers not pseudopapilionaceous; fleshy digitate body absent |
| 5 | Calyx open at apex before anthesis, remaining campanulate |
| 5' | Calyx closed before anthesis, splitting into 2-5 lobes. |
