Scouleria marginata

Stem leaves 3-3.5(-4) × 1-1.3 mm, margins multistratose throughout except 2-stratose at apex (pseudocosta in cross section with chlorophyllose outer epidermal cells and small, thick-walled inner cells), toothed or entire; basal; laminal cells rectangular to quadrate, 15-40 × 7-10 µm, juxtacostal cells shorter; medial and distal laminal cells 10-15(-18) µm; marginal laminal cells with stereid cells 150-200 µm. Peristome absent.

Exposed to submerged in streams or rivers, rocks, particularly granitic; moderate to high elevations (1000-1800 m); B.C.; Calif., Idaho, Mont., Oreg, Wash.