A procumbent evergreen shrub, much-branched, forming low tufts 3 to 6 in. high; branches tortuous, very leafy, glabrous, rooting freely along the ground. Leaves opposite, oval or oblong, 1⁄8 to 1⁄3 in. long, scarcely half as wide, with the margins so much recurved as almost to hide the undersurface, glabrous and dark glossy green above, glabrous or sometimes with a whitish mealy down beneath; stalk one-fourth to half as long as the blade. Flowers rosy or nearly white, about 1⁄4 in. in diameter, produced in May in short terminal clusters, two to five together. Corolla erect, bell-shaped, with five lobes. Calyx with five deep lobes half as long as the corolla. Stamens five, shorter than the corolla. Seed-vessel a dry capsule, with two or three divisions, many-seeded.
Native of the Alpine summits and sub-arctic regions of the three northern continents, and the only species known. Found on the Scottish highlands. It needs a peaty soil. In the south of England it does not thrive well; the summer is usually too hot and dry for it. Some cool damp spot on the lower part of the rock garden should be selected for it.