Perennials or subshrubs, (7-)8-14 cm (cespitose), faintly aromatic. Stems 5-8, silver-gray, densely tomentose. Leaves persistent, silver-green, mostly basal; proximalmost blades 3-4 × 1-1.5 cm, 1-pinnately lobed, lobes mostly 2-3 mm wide; blades of flowering stems somewhat reduced, (1-)2-3(-5) × 0.15 cm, mostly entire; apices rounded, faces densely hairy. Heads borne singly or (clustered in 2s and 3s on lateral branches; peduncles 0 or to 5 mm) in paniculiform arrays, (2-)4-9 × 1-1.5(-2) cm. Involucres broadly campanulate, 4-5(-7) × 2-3 mm. Phyllaries (ovate, margins broadly scarious) densely tomentose. Florets: pistillate 8-10 (2-2.8 mm); functionally staminate 22-32; corollas pale yellow, 2.2-4.5 mm, glandular. Cypselae (light brown) ellipsoid, flattened (faintly nerved), 1.5-2 mm, sparsely hairy, glabrous or resinous.

Flowering mid-late summer. Barren clay and gravelly soils; 1800-2000 m; Mont., Wyo.

Although Cronquist observed that Artemisia porteri may be an autopolyploid derivative of A. pedatifida, morphologic similarities to northerly cespitose taxa suggest a more complex origin.

Artemisia porteri is in the Center for Plant Conservation´s National Collection of Endangered Plants.