| 1 | Corolla red, pink, purple or white |
| 1' | Corolla yellow, sometimes reddish with age or veines crimson; pods straight or slightly curved |
| 2 | Pods with 4 conspicuous longitudinal wings, 4-8 mm wide |
| 2' | Pods without wings, strongly curved, 1-2 mm wide |
| 3 | Pod inflated, more than 5 mm wide, adaxial suture deeply impressed, almost dividing the pod longitudinally |
| 3' | Pod linear, slender, less than 5 mm wide, adaxial suture not deeply impressed |
| 4 | Pods laterally flattened, distinctly torulose; diffuse annual; inflorescence 1-4(-5)-flowered |
| 4' | Pods terete or slightly compressed, not flattened, smooth or obscurely torulose |
| 5 | Perennials with woody rootstocks; inflorescence umbellate, long-pedunculate, usually 2-8 (or more)-flowered; standard 8-15 mm long |
| 5' | Annuals ; inflorescences 1-2(-4)-flowered; standard generally less than 8 mm long |
| 6 | Leaves adpressed-sericeous, silvery; beak of keel usually stained; plant of sandy seashores |
| 6' | Leaves green, subglabrous or thinly pilose, not silvery-sericeous |
| 7 | Calyx 2-lipped; calyx-teeth unequal |
| 7' | Calyx not 2-lipped; calyx-teeth subequal |
| 8 | Leaflets of upper leaves at least 4 times as long as wide |
| 8' | Leaflets of upper leaves usually up to 3 times as long as wide |
| 9 | Corolla 10-15 mm long, about twice as long as calyx; plant glabrescent |
| 9' | Corolla 6-10 mm long, up to 1.5 as long as calyx; plant more or less villose |
| 10 | Stems and calyces clothed with long spreading hairs; peduncles slender, elongate, up to 5 cm long |
| 10' | Stems and calyces clothed with short, crispate subadpressed hairs; peduncles short, generally less than 2 cm long |
| 11 | Leaflets 10-15 mm long, 5-10 mm wide; peduncle generally shorter than subtending leaf; pod 2-4 mm wide |
| 11' | Leaflets 2-10(-14) mm long, 1.5-5 mm wide; peduncle usually equalling or exceeding subtending leaf; pod generally less than 2 mm wide |
