Annual, glabrous or sparsely pubescent herb, up to 40 cm tall; stem dichotomously branched from the base, branches slender; leaves very variable indeed in lobation; radical leaves alternate, entire or toothed, pinnatifid, cauline leaves stem clasping or amplexicaul with auricled base, uppermost segments linear, margins finely sinuate-toothed, glabrous; heads few flowered, sessile or peduncled, panicled, homogamous, yellow, purple or blue; involucre usually narrow, bracts few-seriate, thinly herbaceous, margins often membranous; inner slender, subequal, outer very short; receptacle flat, naked, all florets ligulate; achenes much compressed or flattened, ovoid, oblong or narrow beaked, faces 3 or more, transversely rugose or smooth, ribbed; puppus persistent, copious hairs, very slender, simple, usually soft, white, thin.