Rhizomatous perennial. Stems simple, erect, 15–90 cm. Herbage tomentose, leaves sometimes glabrate above, aromatic. Leaves cauline, sessile to short-petiolate, 1–9 cm long, linear-lanceolate to obovate, entire, lobed or deeply divided. Inflorescence open to dense, racemose to paniculate, leafy below. Involucre campanulate, 2–5 mm high; phyllaries green to brown, glabrate to tomentose; receptacle glabrous. Disk flowers 10 to 55, perfect and female, glabrous to glandular; corolla 1.5–2.5 mm long; yellow. Achenes glabrous, ca. 0.5 mm long (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX)
In addition to the nominal infraspecific taxon, we have the following: A. l.
(Rydb.) D.D. Keck A. l.
(Nutt.) D.D. Keck.