Perennials, 50–100(–300) cm (not cespitose), pleasantly aromatic (fibrous-rooted, rhizomes horizontal, relatively short). Stems 2–5, erect, brown, mostly simple (bases woody), sparsely tomentose. Leaves cauline, bicolor (white and green); blades lanceolate, 7–15 × 1–2.5 cm, serrate (teeth ca. 2 mm), faces densely tomentose (abaxial) or glabrate (adaxial). Heads (peduncles 0 or to 2 mm) in racemiform arrays 10–15 × 5–15 cm. Involucres campanulate, 2.5–3 × 2–2.5 mm. Phyllaries lanceolate (margins hyaline), densely tomentose. Florets: pistillate 3–5; bisexual 9–10; corollas pale yellow, 1.5–2 mm, sparsely glandular. Cypselae ellipsoid, ca. 1 mm, glabrous. 2n = 36.
"Rhizomatous perennial 1–3 m; stem glabrous or nearly so below the infl; lvs numerous, lanceolate or lance-linear, acuminate, sharply and regularly serrate, 8–15 cm × 8–25 mm, green and essentially glabrous above, densely white-tomentose beneath, sometimes with a pair of small, stipule- like lobes at base; infl ample, generally leafy, invol 2.5–3.5 mm; disk-cors 2 mm; achenes ellipsoid, not nerved or ridged; 2n=36. Prairies and low ground; Minn. and Io. to Ill., and intr. in N.Y. Aug.–Oct."