Digitaria didactyla is a species of grass known by the common names blue couch, Queensland blue couch, blue serangoon grass, green serangoon grass, blue stargrass, and petit gazon (in Mauritius). It is native to Mauritius, Réunion, parts of mainland Africa, and Madagascar. It has been introduced widely outside its native range, mainly for use as a pasture and turf grass. It has naturalized in some regions.