1 | Plants perennial with a tough, woody rootstock; disk purplish or pinkish; rays (when present) with a purplish base |
1' | Plants annual, rarely perennial; disk yellow; rays (when present) white |
2 | Cauline leaves simply pinnatisect, with entire or occasionally dentate, oblong lobes; achenes with a very short, inconspicuous corona |
2' | Cauline leaves bipinnatisect; achene with a conspicuous, well-developed corona |
3 | Plant densely grey-lanuginose, generally procumbent to ascending and only in coastal habitats |
3' | Plant glabrous, subglabrous or thinly pilose to pubescent, leaves sometimes densely hairy, but not lanuginose |
4 | Receptacular scales linear-filiform or linear-subulate, 0.2-0.3 mm wide |
4' | Receptacular scales oblong-obovate or obcuneate, 1-4 mm wide |
5 | Achenes longtitudinally ribbed, not or scarcely tuberculate |
5' | Achenes conspicuously tuberculate |
6 | Achenes caducous at maturity, soon falling from receptacle |
6' | Achenes persistent at maturity, forming a dense subglobose head |
7 | Phyllaries with a conspicuous, fuscous margin; tube of disk-florets goblet-shaped, abruptly dilated above the middle |
7' | Phyllaries with a pale, hyaline or stramineous margin; tube of disk-florets not abruptly dilated above the middle |
8 | Capitula discoid; receptacular scales membranous, oblong-obovate; achenes clavate-obconical, not compressed dorsiventrally |
8' | Capitula radiate; receptacular scales cartilagenous, obcuneate; achenes more or less compressed dorsiventrally |
9 | Receptacular scales truncate or obscurely muticous at apex, usually pallid in fruit |
9' | Receptacular scales conspicuously cuspidate, mucronate or acuminate, often dark bronze-purple in fruit |
10 | Receptacular scales strongly acuminate; achenes 1.75-2.5 mm long, 2-3-ribbed on either face |
10' | Receptacular scales cuspidate or mucronate; achenes 2.5-3 mm long, often (but not always) distinctly 8-10-ribbed on either face |