| 1 | Woody climbers. Leaves palmately compound, petioles twisting. Fruits with 2-4 lateral wings (wings sometimes ridge-like) |
| 1' | Trees. Leaves simple, petioles not twisting. Fruits with 2 apical wings or fruits surrounded by an inflated cupule |
| 2 | Deciduous trees. Inflorescences without bracts, flowers minute, buds less than 1.5 mm diameter. Fruits with 2 apical wings |
| 2' | Evergreen trees. Inflorescences with bracts, flowers conspicuous, buds more than 2 mm diameter. Fruits surrounded by an inflated cupule.. |
