Artemisia porteri Cronq.

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.

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.

Artemisia porteri is a species of flowering plant in the aster family known by the common names Porter's sagebrush, Porter's wormwood, and Porter mugwort. It is endemic to Wyoming in the United States, where it is known from Fremont, Johnson and Natrona Counties.

This plant is a perennial herb or small subshrub, growing in clumps or mats up to 14 centimeters tall. There are several woolly stems with silvery lobed leaves. Bell-shaped woolly flower heads contain small yellowish disc florets.

This plant grows in the badlands of central Wyoming. It can be found on substrates of mudstone and eroding clay which are mostly barren of vegetation.