Bark exfoliating readily in reddish brown or blackish sheets. Leaves: petiole (1–)3–18(–54) mm; blade ovate, (1–)2–8(–10) × (1–)1.3–6.3(–8.5) cm, margins crenate to dentate, teeth (13–)19–51(–69). Inflorescences (7–)15–35-flowered. Flowers: sepals triangular-ovate, 1.5–3(–3.8) mm; petals white, 6–11 mm; styles 3.5–5(–7) mm. 2n = 32.

Flowering May–Aug(–Oct). Stream banks, forested canyon bottoms, rocky slopes, cliffs; 1500–3000(–3800) m; Ariz., Colo., N.Mex., Wyo.; Mexico (Chihuahua, Nuevo León).