A dwarf evergreen shrub 6 to 12 in. high, branches erect or spreading; young ahoots not downy, completely hidden by the leaves. Leaves 3⁄16 in. long, 1⁄12 in. wide, without stalks, closely pressed to the shoot, tapering to a blunt apex; inner surface hollowed, outer surface ridged or keeled, thus giving a four-angled character to the twig which, leaves and all, is about 1⁄8 in. wide. Flowers nodding, solitary on glabrous thread-like stalks, 1⁄3 in. long, opening from the leaf-axils in April. Corolla cup-shaped, with five shallow reflexed lobes, 1⁄4 in. wide, pure white; stamens very short, with white stalks; anthers brown, each prolonged at the back into a bristle; style glabrous, half as long as the corolla. Calyx of five sepals thickened at the base, 1⁄10 in. long, pointed, jagged at the margins, often red or reddish.
Native of the mountains of western N. America, from California to Alaska. It is well distinguished from the common C. tetragona by the thick ridge down the back of the leaf, which in the other is grooved there. An interesting if not a showy shrub and quite hardy.