Oldfield Three-awn

Aristida oligantha is a species of grass known by the common names prairie threeawn, oldfield threeawn and ant rice.

It is native to the United States and southern Canada, and it is known from northern Mexico. It is a grass of many types of habitat, and it grows easily in dry areas with sandy or gravelly soils. It appears in disturbed and burned areas and is sometimes a weed of roadsides and railroads.