uncus roemerianus is a species of flowering plant in the rush family known by the common names black rush, needle rush, and black needle rush. It is native to North America, where its main distribution lies along the coastline of the southeastern United States, including the Gulf Coast. It occurs from New Jersey to Texas, with outlying populations in Connecticut, New York, Mexico, and certain Caribbean islands.
This rush is a perennial plant forming tufts of rough, rigid stems and leaves. It is gray-green in color. The plant may appear to be leafless at first glance, but what look like sharp-pointed stems are actually stiff leaves rolled tightly to form pointed cylinders. The true stems are tipped with inflorescences. It grows from a rhizome. This plant is variable in appearance. Its size and shape depend on environmental conditions in its salt marsh habitat. In areas with low soil salinity the plant can exceed two meters in height, whereas in high-salinity areas the rush is dwarfed, sometimes measuring under 30 centimeters (12 in.) tall.