| 1 | Flowers yellow. Staminal tube hairy inside, split in apical half, the filaments of the 2 parts connate to apex. Fruit with a second, smaller wing. |
| 1' | Flowers pink to deep purple. Staminal tube completely glabrous, all filaments free for ¼. Fruit only with a single large wing. |
| 2 | Keel glabrous, apically with a nearly undivided crest. Fruit (without wing) elliptic |
| 2' | Keel slightly hairy inside, apically inappendiculate. Fruit (without the wings) orbicular. |
| 3 | Leaftip rounded to emarginate, at apex of midrib with a distinct hydathode. Vegetative parts almost glabrous. Outer sepals glabrous except for margin. Wing of fruit broadly attached to halfway, without stipe-like constriction |
| 3' | Leaftip acute to cuspidate, without apical hydathode. Young twigs, petioles and lower side of leaves shortly hairy. Outer sepals shortly hairy. Wing of fruit narrowly attached, stipe-like constricted in basal ⅓ part |
