Mat-forming perennial with prostrate hairy stems. Stems freely branched, rooting at nodes. Leaves opposite with a few large teeth toward the tip. Flowers rose-purple or white, in a head at the tip of a long stalk, resemble the head of a match. Reproduces by seed and stolons. Occurring in low moist areas in open woods and turf, common along the coastal beaches and marshes, preferring open sandy areas often with limestone outcrops. Occurs from Pennsylvania to Florida, Arkansas, Oklahoma, Texas, and in California. Also found in Hawaii, Mexico, Central and South America, the West Indies, Japan and India.