Annuals, 3-12(-30) cm (taprooted). Stems usually 1, erect (usually branched ± throughout). Leaves (sometimes ± fleshy) basal and cauline; alternate; mostly sessile; blades pinnately nerved, linear (or pinnately divided into 2-15 linear lobes), ultimate margins entire, faces glabrous or sparsely floccose-tomentose. Heads radiate, borne singly. Involucres ± hemispheric, 3-6+ mm diam. Phyllaries persistent, 5-13+ in ± 2 series, ± erect (inflexed in late flowering, reflexed in fruit), basally connate, elliptic to ovate, subequal, ± membranous (veiny, tips usually purple). Receptacles flat to convex, smooth or foveolate, epaleate. Ray florets 5-13+, pistillate (sometimes, some pistillate florets lack corollas); corollas sessile (lacking tubes), usually yellow, rarely white (often purplish abaxially, laminae ovate to linear). Disc florets 20-60(-100+), functionally staminate; corollas yellow, tubes shorter to longer than campanulate throats; lobes 5, ± erect, deltate to lanceolate; styles not divided. Cypselae ± ellipsoid, usually 5-6(-10)-ribbed or -angled, usually papillate (papillae becoming mucilaginous when wetted); pappi 0. x = 9.