 The latter are commonly referred to collectively as grass.With around 780 genera and around 12,000 species, the Poaceae is the fifth-largest , following the Asteraceae, Orchidaceae, Fabaceae and Rubiaceae.The Poaceae are the most economically important plant family, providing staple foods from domesticated cereal crops such as maize, wheat, rice, barley, and millet as well as feed for meat-producing animals.