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| 1 Stamens separate, unfused; stipules (at least the lower on the stem) often persistent, foliaceous, not striate; corollas yellow, white, or purple-blue. |
| ..2 Legumes turgid, inflated; corolla white, cream, yellow, blue, or purple; [widespread in our area, especially Coastal Plain] |
| ..2 Legumes laterally compressed; corolla yellow; [primarily montane, elsewhere as an escape from cultivation] |
| 1 Stamens monadelphous or diadelphous; stipules either caducous or well-developed and persistent, and then separate or adnate to the petiole; corollas pink, blue, violet, yellow, or white. |
| ....3 Stamens monadelphous; corollas 7-20 mm long. |
| ......4 Corollas pink |
| ......4 Corollas yellow. |
| ........5 Plants glandular-punctate. |
| ........5 Plants eglandular |
| ..........6 Calyx deeply 5-lobed; upright (rarely sprawling) annual herbs, mostly 8-20 dm tall |
| ..........6 Calyx with the upper 4 lobes connate; decumbent perennial herbs, the stems to 5 dm long |
| ....3 Stamens diadelphous (9 and 1); corollas 3-16 mm long. |
| ............ 7 Foliage punctate-glandular; corollas blue, violet, or white. |
| ............ ..8 Fruit not beaked; corollas 4.5-8 mm long |
| ............ ..8 Fruit beaked, the beak 3-7 mm long; corollas 7-12 mm long |
| ............ 7 Foliage eglandular; corollas purple, pink, red, or white. |
| ............ ....9 Lateral veins of each leaflet lateral veins neatly straight and parallel to one another; leaflets entire; [tribe Desmodieae] |
| ............ ....9 Lateral veins of each leaflet complicatedly and irregularly arrayed; leaflets denticulate; [tribe Trifolieae] |