Plants usually erect, caulescent (rarely acaulescent), 20–150 cm. Stems usually simple, proximally unbranched, very leafy, ± villous with septate trichomes and/or thinly arachnoid tomentose, often glabrate. Leaves: blades oblanceolate or narrowly elliptic, pinnately lobed, longer spines ± stout, usually 1 cm or shorter, abaxial faces glabrous to thinly gray-tomentose, adaxial glabrous; distal narrow, firm, green throughout or unpigmented proximally. Heads 3–10+, ± sessile or pedunculate, usually in spiciform or racemiform arrays, subtended by ± reduced bractlike distal leaves that often do not overtop the heads. Peduncles 0–18 cm. Involucres 2–3 cm. Phyllaries: outer and mid lanceolate to narrowly ovate, spines slender to stout, 1–5 mm; apices of inner acuminate and entire or serrate, or abruptly expanded into scarious, erose-toothed appendages. Corollas white (rarely purple), 22–29 mm, tubes 11–16 mm, throats 4–5 mm, lobes 6–9.5 mm; style tips 4–6 mm. Cypselae 4–6 mm; pappi 18–25 mm. 2n = 34, 36? (as C. foliosum).
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