Proc. Acad. Nat. Sci. Philadelphia 4: 20. 1848.
Subshrubs or shrubs, 50–200 cm. Stems erect, virgately branched. Leaves cauline; alternate; petiolate or ± sessile; blades mostly pinnately lobed (lobes 3–7+, linear to filiform), distal (not lobed) linear to filiform, faces usually sericeous to strigillose, sometimes glabrate or glabrous, usually gland-dotted. Heads disciform, in (ebracteate or nearly so) paniculiform arrays, or borne singly or in glomerules of 1–5+. Involucres ± hemispheric, 4–5+ mm diam. Phyllaries persistent, 10–15+ in 2–3 series, distinct, outer 5–7 herbaceous, inner scarious to membranous (± villous). Receptacles convex; paleae spatulate to cuneiform, membranous, distally ± villous. Pistillate florets 5; corollas 0. Functionally staminate florets 10–25+; corollas whitish, funnelform, lobes 5, erect (filaments connate, anthers distinct or weakly coherent). Cypselae plumply obovoid, obcompressed or weakly 3–4-angled, smooth, ± villous, little, if at all, gland-dotted; pappi 0. x = 18.
w United States.