Psilocarphus brevissimus is a species of flowering plant in the aster family known by the common names short woollyheads, woolly marbles, and woolly heads. The plant is native to western North America — from southwestern Canada, through California, to northwestern Mexico, as well as in southern South America. It grows in moist flats such as vernal pools, wetlands, and similar areas. It is found from sea level to 8,202 feet (2,500 m).