1	"Leaves flexible, tip spine-less"	"Agave attenuata"
1	"Leaves rigid, spine-tipped"	2
2	"Leaves generally not ensiform, lanceolate, less than 10 times longer than wide"	"Agave americana"
2	"Leaves ensiform, linear to lanceolate, 10–20 times longer than wide"	3
3	"Leaves always with marginal teeth; sepals and petals unequal; filaments 35–45 mm long"	"Agave vivipara"
3	"Leaves usually toothless; sepals and petals equal; filaments 50–60 mm long"	"Agave sisalana"