| Habit | Woody vines. | Woody vines. | Woody vines. | Mostly lianas, less frequently woody vines or shrubs. |
| Stipules | Basifixed. | Basifixed. | Basifixed. | Medifixed or basifixed. |
| Inflorescence | Axillary and with an arched axis. | Axillary and erect. | Axillary and erect. | Erect, mostly axillary but frequently cauliflorous. |
| Inflorescence nodes | Multiflorous and secundiflorous, sessile, globose. | Multiflorous and secundiflorous, sessile. | Multiflorous and secundiflorous, sessile. | Multiflorous and secundiflorous, stalked. |
| Flower position | Resupinate (i.e. the standard petal backwards and the set wing-keel petals upwards). | Not resupinate. | Not resupinate. | Not resupinate. |
| Calyx | Cylindrical, 4-lobed, the lobes shorter than the tube and of the same length; upper lobe entire and truncate (wider than longer). | Campanulate, 4-lobed, the lobes having almost the same length and mathching the length of the tube; upper lobe triangulate. | Campanulate, 4-lobed, the lobes having almost the same length and mathching the length of the tube; upper lobe triangulate. | Campanulate, rarely cylindrical, upper edge humped or convex, 4-5-lobed or deeply bilabiate, the lower lobe much longer than the remaining. |
| Standard petal | Pink or purple, pubescent towards the apex, ecallose and spreading or reflexed ca. 90°. | Bright red, pubescent towards the apex, ecallose and spreading. | Mostly purple, rarely reddish-purple, pubescent towards the apex, ecallose, reflexed. | Mostly purple, rarely blue, glabrous, 2-callose, reflexed. |
| Wing petals | Dwarf, much shorter than the other petals and sagittate. | As long as the keel. | As long as the keel. | About twice as long as the keel. |
| Keel petals | Upcurved ca. 90° with a truncate apex, upper margin smooth. | Straight, oblanceolate, apex rounded, upper margin smooth. | Straight, elliptic to obovate, apex rounded, upper margin upper margin dentate, serrate or fimbriate. | Triangular or semilunar, extending distally into a slender, obtuse or truncate beak. |
| Androecium | Pseudomonadelphous, the staminal tube pubescent at the base. | Diadelphous, the staminal sheath glabrous. | Pseudomonadelphous, the staminal tube glabrous. | Pseudomonadelphous, the staminal tube glabrous, rarely pubescent at the base. |
| Anthers | Monomorphic, all fertile. | Monomorphic, all fertile. | Monomorphic, all fertile. | Mostly dimorphic, 5 fertile alternating with 5 sterile or 6 fertile and 4 sterile or anthers monomorphic and all 10 fertile. |
| Intrastaminal disc | 10-lobed. | Entire with a smooth rim. | Entire with a smooth rim. | 10-dentate or 10-lobed. |
| Gynoecium | Ovary sessile, 6-8-ovulate; style not swollen. | Ovary sessile, 5-6-ovulate; style not swollen. | Ovary stipitate, 7-15-ovulate; style not swollen. | Ovary sessile, 2-5 (10)-ovulate; style swollen and frequently flattened distally. |
| Fruit | Oblong-linear, elastically dehiscent; thin ribs at the margins | Shortly oblong, elastically dehiscent, margins lacking ribs or wings | Oblong-linear, elastically dehiscent; upper margin provided with ribs or wings. | Various, cylindrical to flat compressed, indehiscent, passively dehiscent or elastically dehiscent; upper margin smooth or provided with ribs or wings. |
| Seeds | Lenticular with a linear hilum encircling ca. 1/2 of the seed circumference | Lenticular with a linear hilum encircling ca. 1/2 of the seed circumference | Lenticular with a linear hilum encircling ca. 1/2 of the seed circumference | Massive, orbicular or without a defined shape; hilum linear encircling 1/2 to 4/5 of the seed's circumference or short and oblong. |