1	"Leaves simple or divided or with only 1 pair of leaflets"	Zygophyllum
1	"Leaves with 2 or more pairs of leaflets"	2
2	"Leaves alternate; uppermost pair of leaflets largest or of similar size to lowest"	Tribulopis
2	"Leaves in unequal pairs or, by suppression of smaller pair, alternate; uppermost pair of leaflets smaller than lower leaflets"	Tribulus