An order of flowering plants (angiosperms) that includes the bromeliads, grasses, restios, rushes, and sedges. It comprises approximately 18 families and more than 18,000 species, over half of which are grasses (Poaceae). These families in general include plants without showy flowers (except for Bromeliaceae, Xyridaceae, and Rapateaceae) and with a grasslike form. These plants dominate vast areas of the Earth's surface and include some important grain crops, such as corn (Zea mays), rice (Oryza sativa), and wheat (Triticum aestivum), as well as rushes, sedges, grasses used for thatch, and bamboos used for construction.