1	Keel petal much shorter than the vexillum (anthers uniform)		Erythrina
+	Keel petal longer than or equal to the vexillum		(2)
2 (1)	Anthers uniform (vexillum as long as the keel petals; fruit 2-valved and 1-seeded at the top, seedless below)		Butea
+	Anthers dimorphic, alternately dorsifixed and basifixed, the shorter often broader (fruit often with stinging hairs, 2-valved)		Mucuna