Plants 3-12+ dm. Stems puberulent, glabrescent. Leaves mostly cauline; blades ± lanceolate, 5-12(-20+) cm × 5-18(-40+) mm, l/w = 5-9(-14+), abaxially glabrate (pitted, with awl-shaped hairs in pits), adaxially scabrellous, resin-gland-dotted (sometimes pitted). Heads in congested, corymbiform arrays. Peduncles 1-8(-12+) mm. Involucres ± campanulate, 5-7(-8+) × 4-6 mm. Phyllaries 25-35+ in 4-5+ series, glabrescent, margins arachno-ciliolate, the outer lance-ovate, 1-3 mm, inner oblong to linear-oblong, 5-7+ mm, tips acute or rounded-apiculate. Florets 12-25+. Cypselae 3.5-4 mm; pappi fuscous to purplish, outer subulate scales or bristles 20-30, 0.5-3+ mm, intergrading with 35-45+, 5-7+ mm inner subulate scales or bristles. 2n = 34. Flowering Jul-Sep. Bottomlands, ditches, low prairies; 100-1200 m; Man.; Colo., Ill., Ind., Iowa, Kans., Ky., Mass., Minn., Mo., Nebr., N.Dak., Ohio, Okla., S.Dak., Wis.