Plants (40–)100–300(–400) cm; rhizomes creeping, elongate. Stems 1–5+, erect, glabrous or branches of arrays puberulent. Leaves: basal and proximal cauline withering by flowering; mid and distal cauline numerous (to 50+ on taller stems), sessile or nearly so (bases of blades sometimes subauriculate and rounded to short petioles), blades elliptic or lanceolate-elliptic, larger 60–150 × 15–35 mm, little reduced distally, margins serrate to entire, not 3-nerved, obscurely to obviously reticulately nerved, faces barely rugose, glabrous. Heads 35–800 , in paniculiform arrays, sometimes leafy-bracteate, with short or elongate, slightly to strongly recurved, secund branches. Peduncles 4–10 mm, sparsely to moderately strigose; bracteoles 1–3+, linear-lanceolate, usually a few near head grading into phyllaries. Involucres campanulate, 4–6 mm. Phyllaries in 4–5 series, strongly unequal, margins apically ciliate, obtuse to rounded, glabrous; outer ovate-lanceolate, inner linear-lanceolate, relatively broad, 0.7–1.2 mm. Ray florets 6–10; laminae 2–3 × 0.8–1.3 mm. Disc florets 4–7; corollas 3–4 mm, lobes 0.9–1.3 mm. Cypselae (obconic) 1.5 mm, sparsely strigose; pappi 3.5–5 mm. 2n = 18, 36, 54.
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