Common Sneezeweed

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.

Helenium autumnale var. canaliculatum (Lamarck) Torrey & A. Gray; H. autumnale var. fylesii B. Boivin; H. autumnale var. grandiflorum Torrey & A. Gray; H. autumnale var. montanum (Nuttall) Fernald; H. autumnale var. parviflorum (Nuttall) Fernald; H. latifolium Miller; H. parviflorum Nuttall