Poaceae (/poʊˈeɪsi.iː, -siaɪ/ poh-AY-see-e(y)e), also called Gramineae (/ɡrəˈmɪni.iː, -niaɪ/ grə-MIN-ee-e(y)e), is a large and nearly ubiquitous family of monocotyledonous flowering plants commonly known as grasses.

[5] The Poaceae are the most economically important plant family, providing staple foods from domesticated cereal crops such as maize, wheat, rice, oats, barley, and millet for people and as feed for meat-producing animals.

[citation needed] Some members of the Poaceae are used as building materials (bamboo, thatch, and straw); others can provide a source of biofuel, primarily via the conversion of maize to ethanol.

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.

[10] The perianth is reduced to two scales, called lodicules,[8]: 11  that expand and contract to spread the lemma and palea; these are generally interpreted to be modified sepals.

[11]: 113–114 Three general classifications of growth habit present in grasses: bunch-type (also called caespitose), stoloniferous, and rhizomatous.

The C4 grasses have a photosynthetic pathway, linked to specialized Kranz leaf anatomy, which allows for increased water use efficiency, rendering them better adapted to hot, arid environments.

As another example, the whole tribe of Andropogoneae, which includes maize, sorghum, sugar cane, "Job's tears", and bluestem grasses, is C4.

[15] The name Poaceae was given by John Hendley Barnhart in 1895,[16]: 7  based on the tribe Poeae described in 1814 by Robert Brown, and the type genus Poa described in 1753 by Carl Linnaeus.

They became widespread toward the end of the Cretaceous period, and fossilized dinosaur dung (coprolites) belonging to the sauropod titanosaurs have been found containing phytoliths of a variety that include grasses that are related to modern rice and bamboo.

A cladogram shows subfamilies and approximate species numbers in brackets:[14] Chloridoideae (1600) Danthonioideae (300) Micrairoideae (200) Arundinoideae (50) Panicoideae (3250) Aristidoideae (350) Oryzoideae (110) Bambusoideae – bamboos (1450) Pooideae (3850) Puelioideae (11) Pharoideae (13) Anomochlooideae (4) Before 2005, fossil findings indicated that grasses evolved around 55 million years ago.

[18][19] In 2011, fossils from the same deposit were found to belong to the modern rice tribe Oryzeae, suggesting substantial diversification of major lineages by this time.

[20] In 2018, a study described grass microfossils extracted from the teeth of the hadrosauroid dinosaur Equijubus normani from northern China, dating to the Albian stage of the Early Cretaceous approximately 113–100 million years ago, which were found to belong to primitive lineages within Poaceae, similar in position to the Anomochlooideae.

[1] Fossils of Phragmites have been found in the Late Cretaceous of North America, particularly in the Maastrichtian aged Laramie Formation.

[21] However slightly older fossils of Phragmites have been found in the Eastern coast of the US dating the Campanian (such as in the Black Creek Formation).

According to Lester Charles King, the spread of grasses in the Late Cenozoic would have changed patterns of hillslope evolution favouring slopes that are convex upslope and concave downslope and lacking a free face were common.

[33][34] Many types of animals eat grass as their main source of food, and are called graminivores – these include cattle, sheep, horses, rabbits and many invertebrates, such as grasshoppers and the caterpillars of many brown butterflies.

[37] Unlike in animals, the specification of both male and female plant germlines occurs late in development during flowering.

Grasses are also used in the manufacture of thatch, paper, fuel, clothing, insulation, timber for fencing, furniture, scaffolding and construction materials, floor matting, sports turf and baskets.

Bamboo shoots are used in numerous Asian dishes and broths, and are available in supermarkets in various sliced forms, in both fresh, fermented and canned versions.

Many species of grass are grown as pasture for foraging or as fodder for prescribed livestock feeds, particularly in the case of cattle, horses, and sheep.

Such grasses may be cut and stored for later feeding, especially for the winter, in the form of bales of hay or straw, or in silos as silage.

[57][58][48] Despite these challenges, new techniques in Fourier-Transform Infrared Spectroscopy (FT-IR) and improved statistical methods are now helping to better identify these similar-looking pollen types.

In the days leading up to the match it is repeatedly mowed and rolled to produce a very hard, flat surface for the ball to bounce off.

A number of grasses are invasive species that damage natural ecosystems, including forms of Phragmites australis which are native to Eurasia but has spread around the world.

As Virginia Jenkins, author of The Lawn, put it quite bluntly, "Upper middle-class Americans emulated aristocratic society with their own small, semi-rural estates."

In general, the lawn was one of the primary selling points of these new suburban homes, as it shifted social class designations from the equity and ubiquity of urban homes connected to the streets with the upper-middle class designation of a "healthy" green space and the status symbol that is the front lawn.

[68] Many US municipalities and homeowners' associations have rules which require lawns to be maintained to certain specifications, sanctioning those who allow the grass to grow too long.