Grass is the common wor that generally describes monocotyledonous green plants. The family Gramineae (Poaceae) are the "true grasses" and include most plants grown as grains, for pasture, and for lawns (turf). They include some more specialised crops such as lemongrass, as well as many ornamental plants. They also include plants often not recognized to be grasses, such as bamboos or some species of weeds called crab grass.