Plants 40-100 cm; caudices branching; vascular bundles and petiole bases marcescent (attached to old stems for more than a season). Stems 1-10+ , erect, glabrous. Leaves: basal and proximal cauline usually withering by flowering (other rosettes may be present), tapering to long, winged petioles, blades often recurved, linear- lanceolate or -oblanceolate, 100-240 × 8-16 mm, folded along midrib ( V -shaped in cross section), bases usually with (2-)3-8 prominent lateral nerves, apices acute to obtuse, faces glabrous; mid to distal cauline sessile, blades recurved, linear-lanceolate, 50-70 × 8-11 mm, reduced distally, folded, bases with prominent lateral nerves. Heads 30-450 in corymbiform to somewhat paniculiform with rounded corymbiform branches (robust plants) arrays, branches and peduncles strigillose. Peduncles 2.8-4 mm, moderately short-hispido-strigose, lanceolate bracteoles 0-1. Involucres narrowly campanulate, 4.5-6 mm. Phyllaries (14-18) in 3-4 series, unequal, obtuse, broad, striations weak, obtuse to rounded, glabrous. Ray florets 7-9; laminae 4.5-5.5 × 0.4-0.5 mm. Disc florets 6-10; corollas 4.5-5.2 mm, lobes 0.7-1.8 mm. Cypselae 1.5-2.2 mm, glabrous; pappi 3.5-4 mm (apically clavate). 2n = 18. Flowering Sep-Oct. Wet prairielike sites and marshy ground; 100-400 m; Man., Ont.; Ill., Ind., Mich., Minn., Mo., Ohio, Wis.