Rush, a plant, usually a perennial, that grows in wetlands and in or near lakes and streams. Rushes have rounded stems that are either hollow or filled with pith. Their leaves are either grasslike or reduced to scales, and their tiny flowers are shaped like lilies. The fruits are three-celled capsules containing many seeds.

The common rush of North America, Europe, and Asia grows to a height of four feet (1.2 m). It is grown in Japan for making mats, baskets, and ropes. In earlier times rushes were strewn on floors in place of carpets. The pith of some kinds was soaked in grease and formed into candles called rushlights.

There are more than 800 species of rush. A number of other plants called rushes, including the bulrush and the horsetail rush, are not true rushes. Sedges are often confused with rushes. Sedges, however, have solid, usually triangular stems, bristly or scaly flowers, and one-celled fruits.

Rushes belong to the family Juncaceae. The common rush is Juncus effusus.