1	"Plant a small tree to 6 m tall; receptacle scales folded lengthwise, keeled, enlarging greatly with age"	Montanoa
1	"Plant a herb or shrub; receptacle scales not entirely as above"	2
2	"Involucral bracts enlarging and forming a woody capsule enclosing the achenes; pappus absent"	3
2	"Involucral bracts not as above; achenes not enclosed; pappus often present"	5
3	"Enlarged involucral bracts not covered with spines"	Melampodium
3	"Enlarged involucral bracts covered with spines"	4
4	"Spiny herb to 1m tall; capitula of 2 types on a single plant; involucral bracts united to form a single burr-like capsule"	Xanthium
4	"Spineless prostrate herb; capitula all similar; each involucral bract enclosing an achene to produce a burr-like capsule, several of which are borne on a common receptacle"	Acanthospermum
5	"Receptacle bracts folded in 2 and embracing the disk achenes; leaves usually entire, toothed or shallowly lobed (deeply lobed in Tithonia), 3-veined and rough to touch; receptacle usually flat or convex"	6
5	"Receptacle bracts not as above; leaves not usually as above; receptacle often conical or cylindrical"	9
6	"Anthers with collars around filaments; capitula solitary on long stalks, often large and showy"	7
6	"Anthers without collars around filaments; capitula not as above"	8
7	"Stalks hollow and inflated below capitula; receptacle bracts shallowly lobed; leaves deeply lobed"	Tithonia
7	"Stalks not hollow and inflated below capitula; receptacle bracts not lobed; leaves entire or toothed (sunflowers)"	Helianthus
8	"Plant a trailing herb, rooting at nodes; ray florets female"	Wedelia
8	"Plant an erect shrub; ray florets lacking stamens and pistils"	Encelia
9	"Leaves usually alternate, at least on upper stems (coneflowers)"	10
9	"Leaves usually opposite throughout"	12
10	"Receptacle bracts spiny, longer than disk florets, without conspicuous resin ducts, persistent; ray florets often female, sterile"	Echinacea
10	"Receptacle bracts not spiny, shorter than disk florets, with 2 conspicuous resin ducts, deciduous; ray florets lacking stamens and pistils"	11
11	"Ray florets brown-purple; achenes compressed"	Ratibida
11	"Ray florets yellowish; achenes not compressed"	Rudbeckia
12	"Leaves simple, entire; involucral bracts in 2–many rows; capitula solitary"	13
12	"Leaves mostly divided; involucral bracts usually in 2 rows, outer and inner usually different; capitula solitary or several together"	15
13	"Capitula often on hollow inflated stalks; disk florets often with 1 lobe longer than others"	Zinnia
13	"Capitula not on hollow inflated stalks; disk florets with all lobes about equal"	14
14	"Pappus of a few short scales or a crown; ray florets with a conspicuous tube"	Heliopsis
14	"Pappus of about 3 short bristles; ray florets tubeless or virtually so"	Sanvitalia
15	"Capitula solitary on long stalks, large, nodding; pappus of 2 small teeth or absent; plant with tuberous roots"	Dahlia
15	"Capitula not entirely as above; pappus often of short bristles, sometimes a crown or absent; plant without tuberous roots"	16
16	"Achenes with a conspicuous narrow beak at the apex"	Cosmos
16	"Achenes not conspicuously beaked at the apex"	17
17	"Achenes compressed, often winged or with thickened margins"	Coreopsis
17	"Achenes compressed or not,without wings or thickened margins"	Bidens