Biennials [annuals or perennials, shrubs, or dwarf trees], 10-80 cm. herbage spiny . Stems erect or spreading, simple to branched distally or throughout. branches ascending to spreading. Leaves basal and cauline [all cauline]; petiolate or sessile; blade margins dentate to pinnately lobed, ± spiny, faces ± tomentose or glabrate. Heads discoid, borne singly or in corymbiform arrays. Involucres hemispheric to campanulate. Phyllaries many in several series. outer ovate to lanceolate, bases appressed; (at least outer ± leaflike); middle smaller, scarious, margins spiny-dentate or -lobed, apical appendages spine-tipped, inner apices spreading, membranous, white to stramineous, raylike, entire . Receptacles flat to conic, epaleaete scaly or bristly (each floret surrounded by ± connate, membranous scales dissected into linear lobes). Florets many; corollas yellow to maroon, tubular-funnelform, lobes triangular; anther bases tailed, linear-oblong, apical appendages acute; style branches: fused portions ca. 0.5 mm, with basal nodes glabrous or minutely hairy, distally puberulent. distinct portions tapered, not or scarcely separating. Cypselae cylindric to fusiform, not ribbed, without apical rim. hairy with forked, 2-celled hairs, attachment scars basal-oblique; pappi readily falling, of many persistent bristles in 1 series, basally connate in groups of 3-10, plumose. x = 9, 10.
Heads discoid, the fls all tubular and perfect; invol bracts several- seriate, the outer spiny, the inner with innocuous, elongate, eventually spreading, stramineous tip; receptacle flat, chaffy, its bracts connate below, each one split above into bristles; cor hardly divided into tube and limb, with short lobes; filaments glabrous; anthers with a firm, narrow, apical appendage, evidently tailed at the base; style with an abrupt change of texture below the very short, erect, papillate branches; achenes basifixed, cylindric, truncate, nerveless, densely hairy; pappus a single series of coarse, plumose bristles, these chaffy-flattened toward the base and tending to be irregularly connate into groups; spiny herbs with alternate, toothed to pinnatifid lvs and medium-sized to rather large heads. 28, Eurasia and n. Afr.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.