| 1 | Leaflets minutely puberulous or pubescent on both surfaces. |
| 1' | Leaflets glabrous on both surfaces, or usually only minutely puberulous or pubescent on the lower surface, or rarely sparsely, fugaciously puberulous above. |
| 2 | Leaflets glabrous on both surfaces |
| 2' | Leaflets usually only minutely puberulous or pubescent on the lower surface, rarely sparsely, fugaciously puberulous above |
| 3 | Stamens 9, perhaps all fertile, the uppermost staminode absent |
| 3' | Stamens not all fertile, stamens and staminodes 10, the uppermost staminode present |
| 4 | Calyx lobes with spinescent outgrowths or warts |
| 4' | Calyx lobes smooth, unarmed |
| 5 | Leaves 3-jugate |
| 5' | Leaves often 4- or 5-jugate |
| 6 | Leaflets with apex shortly acuminate or acute. (Ovary warty, 1- or 2-ovuled).. |
| 6' | Leaflets with apex obtuse, the very tip slightly notched.. |
| 7 | Calyx bearing some distinct, spiny outgrowths often at the upper half |
| 7' | Calyx bearing loosely, irregularly, minute, spiny outgrowths on the outer surface |
| 8 | Leaflets 3- or 4-jugate. Petals hairy on the longitudinal, central part |
| 8' | Leaflets often 5- or 6-jugate. Petals glabrous inside |
| 9 | Ovary glabrous in the longitudinal, central part |
| 9' | Ovary all densely woolly |
| 10 | Undersurface of the leaflet usually densely tawny hirsute, sometimes slightly glabrescent |
| 10' | Undersurface of the leaflet sparsely and minutely puberulous, glabrescent, sometimes almost glabrous except on the midrib 8. |
