Annuals or biennials, 20–70+ cm; fibrous-rooted (caudices relatively short, weak). Stems 1 (striated, frequently hollow, often pink-to purple-tinged), glabrous or leaf axils sparsely tomentose. Basal leaves (and proximal cauline) obscurely petiolate; blades obovate to oblanceolate, sometimes lyrate (lateral lobes to 5 pairs, terminal lobes larger than laterals), 50–150+ × 10–30+ mm, bases tapering, ultimate margins crenate to irregularly undulate. Cauline leaves gradually reduced (weakly clasping, similar to basal). Heads 8–30+ in umbelliform or cymiform arrays (robust plants with multiple arrays). Peduncles bracteate, glabrous or bases tomentose. Calyculi conspicuous (bractlets 2.5–4 mm). Phyllaries (13–)21, green, 5–7 mm, glabrous. Ray florets (8–)13; corolla laminae 7–9 mm. Disc florets 35–50+; corolla tubes 2.5–3.5 mm, limbs 2–3 mm. Cypselae 1–1.5 mm, sparsely hirtellous on ribs or glabrous; pappi 3–4 mm. 2n = 46.
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