Annuals, biennials, or perennials, 10-80(-200+) cm; taprooted. Stems usually 1, erect, branched distally, glabrous or hairy (internodes winged, margins spiny, faces ± scabrellous and/or sparsely arachnose). Leaves basal and cauline (mostly cauline at flowering); basal ± petiolate, distal sessile; blades oblong or lanceolate to oblanceolate or linear, margins pinnately lobed to dentate, usually strongly spiny (faces ± scabrellous and/or sparsely arachnose). Heads borne singly (axillary and terminal) or in ± spiciform arrays. Peduncles usually 0 (heads in axils of ± foliaceous bracts; if peduncles produced, not inflated, strongly bracteate). Calyculi 0. Involucres campanulate to urceolate, 8-12[-16] mm diam. (larger in fruit). Phyllaries 24-30+ in 3+ series, lanceolate to lance-linear (± flat proximally), unequal to subequal, margins little, if at all, scarious, apices spine-tipped. Receptacles conic to hemispheric, smooth, glabrous, paleate; paleae winged (each palea enfolding, adnate to, and shed with cypsela). Florets 30-60+; corollas yellow. Cypselae (each shed with its enfolding palea) brownish, obcompressed, ± obovoid, not beaked, ribs 0, glabrous; pappi 0 or persistent (fragile), of 2-4[-5] whitish to stramineous, subequal, setiform-aristate scales plus 0-4 muticous to lanceolate scales in ± 1 series. x = 10.