Taprooted biennial or perennial with a simple or branched caudex. Stems ascending to erect, 5–50 cm. Herbage villous to glabrate. Leaves: basal and cauline, petiolate; blades 1–6 cm long, ovate, 1 to 2 times pinnately divided into linear segments; cauline reduced, becoming once pinnate. Inflorescence paniculate; bracts linear above. Involucre campanulate, 2–4 mm high; phyllaries green to brown, glabrous to villous; receptacle glabrous. Disk flowers 15 to 50, female and male, glabrous; corolla ca. 2 mm long; green, yellow, or red. Achenes glabrous, up to 1 mm long (
Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).
We have three infraspecific taxa in Montana in addition to the nominal taxon, which are treated as varieties by Lesica (2012):
subsp.
borealis (Pallas) Hall & Clements (= var.
borealis (Pall.) M. Peck)
subsp.
caudata (Michx.) Hall & Clements (= var.
caudata (Michx.) E.J. Palmer & Steyermark)
and subp.
pacifica (Nutt.) Hall & Clements (= var.
scouleriana (Hook.) Cronquist [Lesica 2012]).