Plants: to 12 cm. Stems: hooked at apices. Stem: leaves 1.2–2.2 mm wide; alar cells shorter, wider than basal cells, 18–38 × 12–25 µm; medial laminal cells 40–90 × 5–9 µm. Branch: leaves 2.2–4 × 0.9–1.3 mm. Seta: 1.7–3 cm. Capsule: arcuate when dry, ellipsoid when moist, 2–3.4 mm.
Soil, litter, and rock in montane coniferous forests of Pacific Northwest, occasionally extending into alpine tundra. moderate to high elevations (300-2500 m). Alta., B.C., Alaska, Colo., Idaho, Mont., Oreg., Wash.
Plants of Rhytidiopsis robusta in subalpine forest and alpine tundra are generally smaller, with leaves 2.5–3.5 mm and leafy stems 3–4 mm wide.