Plants (15–)30–65 cm. Basal leaves spatulate to oblanceolate, 50–200 × 4–25 mm, faces gray-pubescent. Cauline leaves 8–140 mm, distal usually flagged. Heads 3–30. Involucres: staminate 5–8 mm; pistillate 7–12 mm. Phyllaries distally black, dark brown, light brown, or olivaceous. Corollas: staminate 3.5–5 mm; pistillate 4–6 mm. Cypselae 1–1.5 mm; pappi: pistillate (7–)8–10 mm. 2n = 28, 56.

Flowering summer. Alluvial soils in moist willow thickets subject to intermittent flooding along streams, montane to subalpine zone; 0–3000 m; Alta., B.C., Man., N.W.T., Ont., Que., Sask., Yukon; Alaska, Colo., Idaho, Mont., Utah, Wash., Wyo.