Perennials, 50–130 cm. Stems 1(–7), branched distally, strongly winged, sparsely to densely hairy proximally, moderately to densely hairy distally. Leaves usually moderately to densely hairy, sometimes glabrous; basal blades (withered by flowering) lanceolate, oblanceolate, or obovate, entire or weakly lobed; proximal and mid blades obovate to oblanceolate, usually dentate or entire; distal blades oblanceolate to lanceolate, entire or dentate. Heads 5–70(–100+) per plant, in paniculiform arrays. Peduncles 3–10 cm, moderately to densely hairy. Involucres globoid, 8–20 × 8–23 mm. Phyllaries (connate proximally) moderately to densely hairy. Ray florets 8–21, pistillate, fertile; corollas yellow, 10–23 × 4–10 mm. Disc florets 200–400(–800+); corollas yellow proximally, yellow to yellow-brown distally, 2.4–4 mm, lobes 5. Cypselae 1–2 mm, sparsely to moderately hairy; pappi of 5–7 entire, aristate scales (0.5–)0.9–1.5(–1.8) mm. 2n = 32, 34, 36.
"Fibrous-rooted perennial 5–15 dm, glabrous to finely strigose or puberulent; lvs numerous, all or mainly cauline, lance-linear to elliptic or narrowly ovate, narrowed to a sessile or subpetiolar base, decurrent as wings on the stem, not much reduced upwards, 4–15 cm × 5–40 mm, the lower ones deciduous; heads (1–)several or many in a leafy infl, hemispheric or subglobose, the disk yellow, 8–20 mm wide; rays ca 13 to ca 21, pistillate, mostly 1.5–2.5 cm; pappus- scales generally brownish, ovate or lanceolate, tapering to a short awn, to ca 1 mm overall; 2n=32, 34, 36. Moist low ground; Que. to Fla., w. to B.C. and Ariz. Aug.–Oct. The var. autumnale, with elliptic to oblong or lanceolate, generally toothed lvs 3–6 times as long as wide, occurs from Conn. to Minn., s. to Fla. and Tex. (H. altissimum; H. latifolium; H. parviflorum) The var. canaliculatum (Lam.) Torr. & A. Gray, a usually smaller, sometimes single-headed plant with narrower, mostly subentire lvs 7–12 times as long as wide, occurs from Que. to N.Y., w. to Wis. Other vars. occur westward."