1	"Ovary superior"	2
1	"Ovary inferior"	3
2	"Stems with a caudiciform (`bottle’) base; flowers small, less than 1 cm long"	Beaucarnea
2	"Stems without a caudiciform base; flowers large, greater than 3 cm long"	Yucca
3	"Stamens protruding"	Agave
3	"Stamens enclosed"	Furcraea