1	"Corollas shorter than 10 cm; leaf margins doubly lobed with 3-5 large lobes per side; capsules upright; seeds without 2 longitudinal furrows below the dorsal ridge; lateral surfaces with circular pits/depressions"	2
1	"Corollas longer than 8 cm, usually longer than 10 cm; capsules reflexed; seeds with or without 2 longitudinal furrows below the dorsal ridge; lateral surfaces with or without circular pits/depressions"	3
2	"Corollas 3-4.5(-6) cm long; capsules with 30-60 conical spines, distal spines longer than those below, half to more of capsule length"	"Datura ferox"
2	"Corollas 6-10 cm long; capsules usually with 100-300, subequal, narrow spines, occasionally smooth"	"Datura stramonium"
3	"Corollas with short sinuses between the lobes, without interacuminal lobes; calyx lobes equal"	4
3	"Corollas without sinuses between the lobes, often with interacuminal lobes; calyx lobes unequal"	5
4	"Seeds golden brown to dark brown, with a distinct dorsal ridge; capsules with conical spines 0.2-0.5 cm long; corollas often double or triple, often colorful both externally and internally"	"Datura metel"
4	"Seeds black, without a dorsal ridge; capsules with narrow spines 1-3.2 cm long; corollas white with purple throats"	"Datura discolor"
5	"Corollas with prominent interacuminal lobules as long as or longer than those on the lobes; seeds with 2 or more longitudinal furrows on each side"	"Datura innoxia"
5	"Corollas without or interacuminal lobules or with lobules shorter than those on the lobes; seeds with only 1 longitudinal furrow on each side"	"Datura wrightii"