Strongly aromatic, herbaceous perennial, dying back ± to woody stem bases each year. Stems ascending to erect, densely sericeous, becoming glabrous below, ribbed, up to c. 1 m long, much-branched toward base. Lvs scattered along stems, densely sericeous on upper and lower surface. Lower cauline lvs petiolate, 1-pinnate with leaflets 2-(3)-pinnatisect, up to c. 30 × 20 cm in lower lvs; ultimate segments oblong-ovate, obtuse, 5-10-(18) × (1)-2- 4-(6) mm, with only the central vein evident. Infl. paniculate; infl. lvs similar to cauline lvs but becoming apetiolate and 1-pinnatisect, finally reduced to < 1 cm long and not lobed. Outer involucral bracts herbaceous or with membranous apex, sericeous; inner bracts sparsely hairy, with broad membranous margins and apex. Capitula 2-4-(5) mm diam.; receptacle pilose; florets many, dull yellow, glabrous. Achenes 0.8-1.3 mm long, brown, obovoid, ± terete, smooth; pappus 0.