Any of the annual or perennial grasses that make up the genus Agrostis, in the family Poaceae (or Gramineae), found in temperate and cool regions and at high altitudes in subtropical and tropical areas. At least 40 species are found in the U.S.; some are weeds, others forage and turf plants. They have slender stems and flat blades. Many spread by creeping stolons. Redtop (A. gigantea) is a hay and pasture grass. Creeping bent (A. stolonifera variety palustris) and colonial bent (A. tenuis) are popular lawn grasses; the many strains of both species are planted in golf courses and bowling greens, where they are closely cut to develop a fine, spongy, firm turf