1	"Heads +- sessile, sometimes in dense 2° clusters"	2
1	"Heads peduncled"	5
2	"Heads 1-flowered, in dense 2° heads; plant +- spiny"	3
2	"Heads 3--20-flowered, solitary or clustered; plant not spiny"	4
3	"Herb, 10--20 dm, stout, erect; leaves large, 1--2-pinnately lobed, spiny-margined; 2° heads spheric"	"Echinops {Echinops sphaerocephalus}"
3	"Shrub, 4--7 dm; leaves small, spine-tipped, margins weakly spiny; 2° heads not spheric, +- concealed by veiny bracts"	"Hecastocleis {Hecastocleis shockleyi}"
4	"Leaf tips generally 3-lobed; pappus not falling in a ring"	Eriophyllum
4	"Leaf tips entire; pappus falling in a ring"	"Orochaenactis {Orochaenactis thysanocarpha}"
5	"Phyllaries unequal, graduated in 2--many series, outer << inner"	6
5	"Phyllaries or phyllary-like paleae +- equal (or outer > inner), in 1--3 series"	10
6	"Pappus of short scales alternating with longer awns or bristles"	7
6	"Pappus of readily deciduous awns or narrow, bristle-like scales, or of scales that are +- dissected into bristles"	8
7	"Annual; leaves linear, generally entire"	"Malperia {Malperia tenuis}"
7	"Perennial herb or subshrub; leaves lanceolate to +- diamond-shaped, generally few-toothed"	"Pleurocoronis {Pleurocoronis pluriseta}"
8	"Shrub; phyllary tips appressed"	"Acamptopappus sphaerocephalus"
8	"Herb; phyllary tips often spreading to recurved"	9
9	"Involucre gummy; pappus awns readily deciduous"	Grindelia
9	"Involucre hairy or glandular; pappus scales often +- dissected into bristles"	Lessingia
10	"Head +- spheric; leaves decurrent"	Helenium
10	"Head cylindric to hemispheric; leaves not decurrent"	11
11	"Phyllary margins +- scarious, white to yellow, red, or purple"	12
11	"Phyllary or phyllary-like palea margins not evidently scarious, generally +- green"	14
12	"Pappus scales bristle-tipped; corollas cream to white or purple-tinged"	Hymenothrix
12	"Pappus scales obtuse to acute; corollas generally yellow"	13
13	"Annual; pappus scales generally 8"	"Bahia {Bahia neomexicana}"
13	"Perennial herb; pappus scales 12--22"	Hymenopappus
14	"Corollas white to purple"	15
14	"Corollas yellow"	16
15	"Fruit 3--9 mm; pappus scale midrib 0; leaves often toothed or lobed"	Chaenactis
15	"Fruit 10--15 mm; pappus scale midrib well developed; leaves entire"	Palafoxia
16	"Outer corollas +- bilateral, much enlarged, ray-like; pappus scales entire or toothed"	"Chaenactis glabriuscula"
16	"Outer corollas generally radial, not or only slightly enlarged; pappus scales plumose or dissected into bristles"	17
17	"Annual or short-lived perennial herb; rhizome 0"	18
17	"Perennial herb with rhizome"	19
18	"Leaf teeth and lobes blunt; involucre densely glandular; pappus scales plumose"	"Layia discoidea"
18	"Leaf teeth and lobes sharp; involucre not glandular; pappus scales dissected into bristles"	"Trichoptilium {Trichoptilium incisum}"
19	"Leaves mostly or all basal"	Raillardella
19	"Leaves basal and cauline, well distributed on stem"	20
20	"Glandless hairs restricted to margins of phyllary-like paleae"	"Anisocarpus scabridus"
20	"Glandless hairs not restricted to margins of phyllary-like paleae"	"Carlquistia {Carlquistia muirii}"