Plants to 50–300 cm. Basal leaves: petioles hollow (sometimes only at base), 15–50 cm, thinly to densely cobwebby; blades 30–60 × 15–35 cm, coarsely dentate to subentire (rarely deeply dissected), abaxially ± thinly gray-tomentose, adaxially green, sparsely short-hairy. Heads in racemiform or paniculiform clusters, sessile to pedunculate. Peduncles 0–9.5 cm. Involucres 15–40 mm diam. Phyllaries linear to linear-lanceolate, glabrous to densely cobwebby, inner often purplish tinged, margins often minutely serrate with fine teeth, puberulent with glandular and or eglandular hairs. Florets 30+; corollas purple, pink, or white, 7.5–12 mm, glabrous or limb glandular-puberulent. Cypselae dark brown or with darker spots, 5–8 mm; pappus bristles 1–3.5 mm. 2n = 32 (Germany), 36 (as A. nemorosum).