Species of tall, robust, leafless aquatic plant growing to 5 m (16 feet) in height, forming a grass-like clump of green stems, triangular in cross section, that rise up from thick, woody rhizomes. Each stem is topped by a dense cluster of thin, bright green stems. It is edible to humans. It was cultivated in ancient Egypt, collected for its stalk or stem, the central pith of which was cut into thin strips, assembled in layers at right angles, pressed together, and dried to form a smooth, thin writing surface as early as the 3rd millennium BCE. Its use spread to the Greeks and then to the Roman Empire. Papyrus can darken and discolor with age. Other products were boats, sails, and cords. The species is now almost extinct in Egypt, but still of importance elsewhere in Africa as a fuel source. It is cultivated throughout the tropics; popular as an ornamental in Europe, Asia, and North America.
