1	"Leaves, cone bracts generally 3 per node; seed cones sessile"	2
1	"Leaves, cone bracts generally 2 per node; seed cones sessile or stalked"	4
2	"Uppermost bud thorn-like; leaf sheath persistent, fibrous"	"Ephedra trifurca"
2	"Uppermost bud narrowed but not thorn-like; leaf sheath deciduous, not fibrous"	3
3	"Seed not beaked; twig yellow-green in youth; leaf base in age recurved, swollen"	"Ephedra californica"
3	"Seed beaked; twig gray-green in youth; leaf base in age not recurved, not swollen"	"Ephedra funerea"
4	"Distal bracts of seed cone fused >= 2/3, fleshy at maturity"	"Ephedra foeminea"
4	"Distal bracts of seed cone free or fused < 1/3, scarious at maturity"	5
5	"Seed generally 1; seed cone stalk <= 2 mm"	"Ephedra aspera"
5	"Seeds generally 2; seed cone stalk <= 11(50) mm"	6
6	"Twig pale green, glaucous in youth; leaf base gray, deciduous; bracts of seed cone broadly ovate"	"Ephedra nevadensis"
6	"Twig bright- to yellow-green in youth; leaf base brown, persistent; bracts of seed cone elliptic"	"Ephedra viridis"