Armoise de l’ouest

Artemisia brittonii Rydberg; A. cuneata Rydberg; A. diversifolia Rydberg, A. falcata Rydberg; A. gnaphaloides Nuttall; A. herriotii Rydberg; A. lindheimeriana Scheele; A. pabularis (A. Nelson) Rydberg; A. paucicephala A. Nelson; A. pudica Rydberg; A. purshiana Besser; A. rhizomata A. Nelson

Stems (gray to white) mostly simple, 30–80 cm, tomentose. Leaves gray; blades linear to narrowly elliptic, 3–11 cm, margins plane (proximalmost entire or apically lobed, lobes to ¹/3 blade lengths; cauline 1.5–11 × 1–1.5 cm, entire or lobed to pinnatifid), faces densely tomentose. Heads in congested, paniculiform or racemiform arrays 5–30 × 1–4 cm. Involucres 3–4 × 2–4 mm. Florets: pistillate 5–12; bisexual 6–30; corollas 1.9–2.8 mm. 2n = 18, 36.

Flowering mid summer–late fall. Disturbed roadsides, open meadows, rocky slopes; 100–3000 m; Alta., B.C., Man., N.B., Ont., P.E.I., Que., Sask.; Ala., Ariz., Ark., Calif., Colo., Conn., Del., Ga., Idaho, Ill., Ind., Iowa, Kans., Ky., La., Maine, Md., Mass., Mich., Minn., Miss., Mo., Mont., Nebr., N.H., N.J., N.Mex., N.Y., N.C., N.Dak., Ohio, Okla., Penn., R.I., S.C., S.Dak., Tenn., Tex., Utah, Vt., Va., Wash., Wis., Wyo.

Subspecies ludoviciana is widespread in North America in diverse habitats. It is the most common subspecies and the most variable morphologically.