Graminaceae

Poaceae (Grasses) Temporal range: Late Cretaceous - recent, 66–0 Ma PreЄ Є O S D C P T J K Pg N
Flowering head of meadow foxtail (Alopecurus pratensis), with stamens exerted at anthesis
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Monocots
(unranked):	Commelinids
Order:	Poales
Family:	Poaceae Barnhart
Type genus
Poa L.
Subfamilies
Anomochlooideae Aristidoideae Arundinoideae Bambusoideae Chloridoideae Danthonioideae Ehrhartoideae Micrairoideae Panicoideae Pharoideae Pooideae Puelioideae
Synonyms
Gramineae Juss.

Gramineae Juss.

Poaceae or Gramineae is a large and nearly ubiquitous family of monocotyledonous flowering plants known as grasses. Poaceae includes the cereal grasses, bamboos and the grasses of natural grassland and cultivated lawns (turf) and pasture. Grasses have stems that are hollow except at the nodes and narrow alternate leaves borne in two ranks. The lower part of each leaf encloses the stem, forming a leaf-sheath. With ca 780 genera and around 12,000 species, Poaceae are the fifth-largest plant family, following the Asteraceae, Orchidaceae, Fabaceae and Rubiaceae.

Grasslands such as savannah and prairie where grasses are dominant are estimated to constitute 40.5% of the land area of the Earth, excluding Greenland and Antarctica. Grasses are also an important part of the vegetation in many other habitats, including wetlands, forests and tundra. The Poaceae are the most economically important plant family, providing staple foods from domesticated cereal crops such as maize (corn), wheat, rice, barley, and millet as well as forage, building materials (bamboo, thatch, straw) and fuel (ethanol).