Greek word Xylon means wood. The tissue that transports water and mineral salts from the root of the plant to different parts of the body is called xylem. It consists of four components. Trachyds, trachea or vessels, xylem fibers and xylem parenchyma. Among them xylem parenchyma is the only living material. Xylem fibers are called wood fibers. Coconut fiber or coir is a type of wood fiber. Ferns and gymnosperms do not have vessels. Besides, the plants of Winteraceae, Tetracentraceae, Trochodendraceae etc. do not have vessels.