Perennials (sometimes flowering first year), (20–)90–200 cm. Stems 1 (from rhizomes) or 2–3+ (from caudices), usually erect (sometimes relatively thick), branched mostly distally (usually relatively leafy proximally, sometimes sparsely leafy distally), glabrous or sparsely arachnose to tomentose. Cauline leaves: proximal (somewhat thick, usually withering early) elliptic, oblanceolate, lanceolate, or linear (sometimes 1–2-pinnately lobed, lobes lanceolate or linear to filiform, sometimes antrorse, bases usually tapering), ultimate margins entire or dentate to denticulate, faces glabrous or ± arachnose to tomentose; distal reduced. Calyculi of 12–18(–30), lanceolate to subulate bractlets, hyaline margins 0.05–0.2 mm. Involucres ± campanulate, 9–12(–16+) × 6–8(–12+) mm. Phyllaries 18–30+ in 2–3 series, lanceolate or linear to subulate, hyaline margins 0.05–0.2 mm wide, faces glabrous or ± arachnose and glabrescent. Receptacles not bristly. Florets 41–100; corollas white (usually each with abaxial purple stripe), 13–20 mm; outer ligules exserted 8–14 mm. Cypselae ± prismatic, 1.4–2.5 mm, ribs extending to apices (± muriculate at 30×), 5 more prominent than others; pappi persistent, of fimbriate crowns or 20–25, blunt teeth (0.01–0.1 mm). Pollen 70–100% 3-porate. 2n = 18.
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