Stems ascending to erect or, rarely, decumbent, usually unbranched, 0.3-1.7(-2.5) dm, densely pubescent. Leaves: blade margins usually entire, sometimes weakly sinuate-dentate, surfaces densely pubes-cent. Flowers: petals white, 4.4-6.9 × (1.9-)2.3-4.2 mm. Fruits often abortive, somewhat torulose, 0.8-1.2 mm wide when fully developed; septum not fenestrate or split longitudinally. 2n = 28.

Flowering May-Jul. Dry alpine scree slopes, glacial moraines, and gravel bars, often on limestone gravels and soils; 500-3000 m; Alta., B.C., N.W.T.

Subspecies maccallae and porsildii share the large flowers, high percentage of abortive fruits, and leaf margins mostly entire, but they differ in indumentum and habitats.