| 1 | Petiole strongly two-winged |
| 1' | Petiole unwinged (pinnae winged in one species) |
| 2 | Pinnae unifoliolate |
| 2' | Pinnae each with two to several leaflets |
| 3 | Inflorescences consisting of lax and pendulous simple racemes or few-flowered umbels, or racemes aggregated into lax racemes, cauliflorous |
| 3' | Inflorescences erect, consisting of pedunculate glomerules, corymbs, umbels, or racemes, either simple, or often aggregated into racemes or panicles |
| 4 | Calyx inflated at least at the mouth, membranous, and strongly longitudinally ribbed. Leaflets sessile, articulated into round pits similar to the pinna-glands |
| 4' | Calyx not inflated, not membranous, not strongly longitudinally ribbed. Leaflets usually petiolulate, if sessile then not jointed into pits similar to the pinna-glands. |
| 5 | Flowers and pods subtended by bracts with a ring-shaped nectary |
| 5' | Flowers and pods not subtended by bracts with a ring-shaped nectary |
| 6 | Flowers present |
| 6' | Fruits present |
