1	"Leaflets 2"	2
1	"Leaflets 3 or more"	3
2	"Leaflets fused at base"	"Larrea {Larrea tridentata}"
2	"Leaflets free at base"	"Zygophyllum {Zygophyllum fabago}"
3	"Leaflets 3, palmate, spine-tipped; stipules spine-tipped"	Fagonia
3	"Leaflets 6--18, pinnate, not spine-tipped; stipules not spine-tipped"	4
4	"Fruit with many tubercles, 0 spines, 10 nutlets"	Kallstroemia
4	"Fruit with many tubercles, 2--4 stout spines, 5 nutlets"	"Tribulus {Tribulus terrestris}"