1	"Leaves flexible, terminal spine absent"	"Agave attenuata"
1	"Leaves rigid, terminal spine present"	2
2	"Leaves with white markings"	3
2	"Leaves without white markings"	4
3	"Leaves linear-ovate, dark-green, margins without threads"	"Agave victoriae-reginae"
3	"Leaves lanceolate, light-green, margins with fine threads"	"Agave filifera"
4	"Leaves lanceolate, 15–25 cm wide; apical tooth greater than 3 cm long"	"Agave americana"
4	"Leaves linear-lanceolate, ensiform, 3.5–12 cm wide; apical tooth 1.5–3.5 cm long"	5
5	"Leaves always with marginal teeth"	"Agave vivipara"
5	"Leaves usually entire"	"Agave sisalana"