1 "Leaf margins spiny" 2 1 "Leaf margins not spiny" 3 2 "Heads many-flowered" Carthamus 2 "Heads 1-flowered, grouped in spheric 2° head" "Echinops {Echinops sphaerocephalus}" 3 "Pappus of bristles, bristles and small scales, or stout needle-like awns" 4 3 "Pappus 0 or of thin, membranous scales or narrow, scale-like awns" 8 4 "Pappus of awns" 5 4 "Pappus of bristles or of bristles and small scales" 6 5 "Leaf +- lanceolate, simple, or pinnately compound, leaflets lanceolate to ovate" Bidens 5 "Leaf linear or dissected into linear lobes" "Thelesperma {Thelesperma megapotamicum}" 6 "Corolla purple; fruit 1--2 per head; herb" "Crupina {Crupina vulgaris}" 6 "Corolla yellow; fruit 18--50 per head; shrub or subshrub" 7 7 "Leaf linear to narrowly elliptic or triangular, rough-hairy or becoming glabrous; corolla 6--10 mm; SW, D" "Bebbia {Bebbia juncea var. aspera}" 7 "Leaf ovate to +- round, tomentose; corolla +- 2.5 mm; CCo, SCo" "Helichrysum {Helichrysum petiolare}" 8 "Ovary and fruit strongly flattened, long-ciliate" 9 8 "Ovary and fruit +- thick, not ciliate" 10 9 "Shrub, strigose" "Encelia frutescens" 9 "Perennial herb, sticky-glandular" "Geraea viscida" 10 "Annual; all or inner phyllaries tapered to long, needle-like tips" "Chaenactis carphoclinia" 10 "Biennial to shrub; phyllaries obtuse to acute or acuminate" 11 11 "Leaf +- cylindric, lobes many, small" "Santolina {Santolina chamaecyparissus}" 11 "Leaf flat, entire to few-lobed" 12 12 "Leaf deeply and coarsely pinnately 3--7-lobed, abaxially gray-green-canescent" "Artemisia palmeri" 12 "Leaf entire or toothed, abaxially glabrous to short-hairy or +- glandular, green" 13 13 "Shrub; leaf +- linear or narrowly oblanceolate" "Eastwoodia {Eastwoodia elegans}" 13 "Perennial herb; leaf elliptic to widely ovate or triangular" 14 14 "Receptacle strongly conic or columnar; corolla dark brown-purple" "Rudbeckia occidentalis" 14 "Receptacle flat to convex; corolla yellow or orange" "Wyethia invenusta"