| 1 | Plants perennial with a thickened, premorse rootstock and tough, fibrous roots |
| 1' | Plants annual with a slender taproot |
| 2 | Pappus-hairs not tousled, rather rigid; apex of peduncle and base in involucre thinly tomentose, often glandular; basal leaves lyrate-pinnatisect with a broad, blunt or acute terminal lobe |
| 2' | Pappus-hairs tousled, softly lanuginose; apex of peduncle and base of involucre glabrous or very sparsely puberulous; basal leaves runcinate-pinnatisect with a small, deltoid-acute, terminal lobe |
| 3 | Plant acaulescent; capitula clustered in the centre of a flat rosette of leaves |
| 3' | Plant with stems |
| 4 | Capitula sessile along the inflorescence-branches; inner phyllaries persistent, becoming swollen, indurated and incurved after anthesis, and covering the achenes |
| 4' | Capitula pedunculate |
| 5 | Stems scapose; leaves (or apparent leaves) all basal, forming a rosette; involucre usually clothed with blackish hairs; capitula small |
| 5' | Stems not scapose, leaves not all basal |
| 6 | Involucre glabrous or subglabrous |
| 6' | Involucre pilose, hispidulous or setose |
| 7 | Leaves obovate or spathulate, shortly toothed or lobed, or subentire, shortly and densely glandular-pilose; achenes tapering to base |
| 7' | Leaves lyrate-pinnatisect, subglabrous or thinly hispidulous-pilose; achenes conspicuously dilated and excavate at base |
| 8 | Peduncles very short, 5-10(-20) mm long, becoming thick and rigid in fruit; stems usually setose with scattered, rigid, spreading bristles |
| 8' | Peduncles slender, or if not slender, up to 20 cm long; stems not setose with spreading, rigid bristles |
| 9 | Capitula small, numerous; involucre 4-5 mm long |
| 9' | Capitula rather large and conspicuous; involucre 7-12 mm long |
| 10 | Receptacle ciliate, but without scales; peduncles and upper parts of stems usually hispidulous |
| 10' | Receptacle scaly, with long, attenuate-caudate membranous scales; peduncles and upper parts of stems usually glabrous or subglabrous |
