Grass is any one of about 8,000 species of the class Monocotyledonae (see monocotyledon), being non-woody plants with fibrous roots and long, narrow leaves enclosing hollow, jointed stems. The stems may be upright or bent, lie on the ground, or grow underground. The flowers are small, with petals or sepals. The leaves grow from the base, and so removal of the tips does not inhibit growth, making grass suitable for lawns and pastures. Cereal grasses, such as rice, millet, maize, and wheat, are cultivated for their edible seeds. Others are grown as food for animals and for erosion control and ornament. Family Poaceae/Gramineae.