Perennials, 20–60(–80) cm, mildly aromatic (rhizomes coarse). Stems 1–3, erect, white, tomentose (on distal branches, hairs appressed) or glabrate. Leaves basal and cauline, bicolor (white and green); blades (basal) linear to broadly lanceolate, 3–7(–10) × 2–5(–6) cm, coarsely pinnately lobed (cauline becoming linear distally), faces tomentose (abaxial) or glabrous (adaxial). Heads in compact to broadly branched, paniculiform arrays 1–20 × 2–6 cm. Involucres broadly campanulate, 4–5 × 3.5–4 mm. Phyllaries (violet-brown) oval (outer) to elliptic or lanceolate, sparsely tomentose. Florets: pistillate 9; bisexual 25–60; corollas yellow, 1.5–3 mm, glabrous (style branches included, erect, linear, relatively short, short-ciliate). Cypselae oblong-linear (angular), 1.2–1.5 mm, glabrous. 2n = 18, 36.
Phenology: Flowering mid summer–early fall.
Habitat: Arctic and alpine tundra, sandy, rocky slopes near shorelines
Elevation: 0–2000 m
Alta., B.C., Man., N.W.T., Nunavut, Ont., Que., Sask., Yukon, Alaska, Idaho, Mont., Oreg., Wash., Asia (Russia).
Artemisia tilesii has a bewildering array of variation in leaf and inflorescence morphology that has been separated into four infraspecific taxa recognized in some floras. I am unable to separate these taxa consistently and am including them within a broad circumscription of the species.