A low semi-evergreen shrub, with mostly prostrate, very slender, wiry stems, armed with tiny decurved spines and more or less covered with bristles. Leaves trifoliolate, the common stalk longer than the leaflets, which are short-stalked, obovate, tapering to the base, sharply and coarsely toothed towards the apex, 1 to 13⁄4 in. long, 1⁄2 to 1 in. wide, glabrous or nearly so on both surfaces. Flowers white, 1⁄2 to 3⁄4 in. across, produced in few-flowered corymbs from the leaf-axils and the ends of erect shoots 6 to 12 in. high. Fruits at first turning red, nearly black when ripe, less than 1⁄2 in. long, and composed of few carpels, sour.
Native of eastern N. America; introduced in 1768, but rarely seen nowadays. It flowers in June and July. Growing very quickly, it soon forms a low, dense tangle, and makes a pretty almost evergreen ground cover.