Editing Poaceae

{{Short description|Family of flowering plants commonly known as grasses}}
{{Redirect|Grass}}
{{Redirect-distinguish|Gramineae|Graminea{{!}}''Graminea''}}
{{pp-vandalism|small=yes}}
{{Automatic taxobox
| name = Grasses
| fossil_range = {{fossilrange|Albian|Present|earliest=Barremian}}<ref name="Yan-2018">{{Cite journal|author1=Yan Wu |author2=Hai-Lu You |author3=Xiao-Qiang Li |year=2018 |title=Dinosaur-associated Poaceae epidermis and phytoliths from the Early Cretaceous of China |journal=National Science Review |volume=5 |issue=5 |pages=721–727 |doi=10.1093/nsr/nwx145|doi-access=free }}</ref>
| image = Meadow Foxtail head.jpg
| image_caption = Flowering head of meadow foxtail (''[[Alopecurus pratensis]]''), with stamens exerted at [[anthesis]]
| taxon = Poaceae
| authority = [[John Hendley Barnhart|Barnhart]]<ref name="APGIII-2009">{{Cite journal |last=Angiosperm Phylogeny Group |year=2009 |title=An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG III |journal=Botanical Journal of the Linnean Society |volume=161 |issue=2 |pages=105–121 |doi=10.1111/j.1095-8339.2009.00996.x|doi-access=free |hdl=10654/18083 |hdl-access=free }}</ref>
| synonyms = Gramineae&nbsp;<small>[[Juss.]]</small>
| synonyms_ref = <ref>{{cite journal|last1=HASTON|first1=ELSPETH|last2=RICHARDSON|first2=JAMES E.|last3=STEVENS|first3=PETER F.|last4=CHASE|first4=MARK W.|last5=HARRIS|first5=DAVID J.|title=The Linear Angiosperm Phylogeny Group (LAPG) III: a linear sequence of the families in APG III|journal=Botanical Journal of the Linnean Society|date=October 2009|volume=161|issue=2|pages=128–131|doi=10.1111/j.1095-8339.2009.01000.x|doi-access=free}}</ref>
| type_genus = ''[[Poa]]''
| type_genus_authority = [[Carl Linnaeus|L.]]
| subdivision_ranks = Subfamilies
| subdivision = * [[Anomochlooideae]]
* [[Aristideae|Aristidoideae]]
* [[Arundinoideae]]
* [[Bambusoideae]]
* [[Chloridoideae]]
* [[Danthonieae|Danthonioideae]]
* [[Ehrhartoideae]]
* [[Micrairoideae]]
* [[Panicoideae]]
* [[Pharoideae]]
* [[Pooideae]]
* [[Puelioideae]]
}}

'''Poaceae''' ({{IPAc-en|p|oʊ|ˈ|eɪ|s|i|.|iː|,_|-|ˌ|aɪ}} {{respell|poh|AY|see|e(y)e}}), also called '''Gramineae''' ({{IPAc-en|g|r|ə|ˈ|m|ɪ|n|i|.|iː|,_|-|ˌ|aɪ}} {{respell|grə|MIN|ee|e(y)e}}), is a large and nearly ubiquitous [[family (biology)|family]] of [[monocotyledon]]ous [[flowering plant]]s commonly known as '''grasses'''. It includes the [[cereal]] grasses, [[bamboo]]s, the grasses of natural [[grassland]] and species cultivated in [[lawn]]s and [[pasture]]. The latter are commonly referred to collectively as '''grass'''.

With around 780 [[genera]] and around 12,000 species,<ref name="Christenhusz-2016">{{cite journal | first1 = M.J.M. | last1 = Christenhusz | first2 = J.W. | last2 = Byng | year = 2016 | title = The number of known plants species in the world and its annual increase | journal = Phytotaxa | volume = 261 | pages = 201–217 | url = http://biotaxa.org/Phytotaxa/article/download/phytotaxa.261.3.1/20598 | doi = 10.11646/phytotaxa.261.3.1 | issue = 3 | url-status = live | archive-url = https://web.archive.org/web/20160729085754/http://biotaxa.org/Phytotaxa/article/download/phytotaxa.261.3.1/20598 | archive-date = 2016-07-29 | doi-access = free | bibcode = 2016Phytx.261..201C }}</ref> the Poaceae is the fifth-largest [[:Category:plant families|plant family]], following the [[Asteraceae]], [[Orchidaceae]], [[Fabaceae]] and [[Rubiaceae]].<ref name="APWeb-2016">{{cite web|url=http://www.mobot.org/MOBOT/research/APweb|title=Angiosperm Phylogeny Website|access-date=20 March 2016|url-status=live|archive-url=https://web.archive.org/web/20160323175342/http://www.mobot.org/MOBOT/research/APweb/|archive-date=23 March 2016}}</ref>

The Poaceae are the most economically important plant family, including [[staple food]]s from domesticated [[cereal]] crops such as [[maize]], [[wheat]], [[rice]], [[oats]], [[barley]], and [[millet]] for people and as [[forage|feed]] for [[livestock|meat-producing animals]]. They provide, through direct human consumption, just over one-half (51%) of all dietary energy; rice provides 20%,<ref>{{cite web|title=Rice is Life|publisher=Food and Agricultural Organization of the United Nations|year=2004|url=http://www.fao.org/rice2004/en/f-sheet/factsheet3.pdf|archive-url=https://web.archive.org/web/20220228205753/https://www.fao.org/rice2004/en/f-sheet/factsheet3.pdf|archive-date=2022-02-28|url-status=dead}}</ref> wheat supplies 20%, maize (corn) 5.5%, and other [[grain]]s 6%.{{citation needed|date=July 2022}} 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]].

Grasses have [[Plant stem|stem]]s that are hollow except at the [[Nodes (botany)|nodes]] and narrow alternate leaves borne in two ranks. The lower part of each leaf encloses the stem, forming a leaf-sheath. The leaf grows from the base of the blade, an adaptation allowing it to cope with frequent grazing.

[[Grassland]]s 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]].<ref>{{Cite web|url=http://www.fao.org/docrep/008/y8344e/y8344e05.htm|title=Grassland of the world|last=Reynolds|first=S.G.|website=www.fao.org|access-date=2016-10-04|url-status=live|archive-url=https://web.archive.org/web/20160920201355/http://www.fao.org/docrep/008/y8344e/y8344e05.htm|archive-date=2016-09-20}}</ref> Grasses are also an important part of the vegetation in many other habitats, including [[wetland]]s, [[forest]]s and [[tundra]].

Though they are commonly called "grasses", groups such as the [[seagrasses]], [[Juncaceae|rushes]] and [[Cyperaceae|sedges]] fall outside this family. The rushes and sedges are related to the Poaceae, being members of the [[Order (biology)|order]] [[Poales]], but the seagrasses are members of the order [[Alismatales]]. However, all of them belong to the [[monocot]] group of plants.

== Description ==
{{plain image with caption|Grassy grass plant.svg|Diagram of a typical lawn grass plant|upright=1.35|caption position=top|triangle=triangle|triangle color=#43d050}}

Grasses may be [[annual plant|annual]] or [[perennial plant|perennial]] [[Herbaceous plant|herbs]],<ref name="Cope-2009"/>{{rp|10}} generally with the following characteristics (the image gallery can be used for reference): The [[Plant stem|stems]] of grasses, called [[Culm (botany)|culms]], are usually cylindrical (more rarely flattened, but not 3-angled) and are hollow, plugged at the [[node (botany)|nodes]], where the leaves are attached.<ref name="Cope-2009">{{cite book|first1=T.|last1=Cope|first2=A.|last2=Gray|title=Grasses of the British Isles|date=2009|publisher=[[Botanical Society of Britain and Ireland]]|location=London |isbn=9780901158420 }}</ref><ref name="Clayton-1986">{{cite book|first1=W.D.|last1=Clayton|first2=S.A.|last2=Renvoise|title=Genera Graminum: Grasses of the world|date=1986|publisher=Royal Botanic Garden, Kew|location=London|isbn=9781900347754 }}</ref> Grass [[Leaf|leaves]] are nearly always alternate and distichous (in one plane), and have parallel veins.<ref name="Cope-2009"/>{{rp|11}} Each leaf is differentiated into a lower sheath hugging the stem and a blade with entire (i.e., smooth) margins.<ref name="Cope-2009"/>{{rp|11}} The leaf blades of many grasses are hardened with [[silica]] [[phytolith]]s, which discourage grazing animals; some, such as [[Imperata cylindrica|sword grass]], are sharp enough to cut human skin. A membranous appendage or fringe of hairs called the [[ligule#Poaceae and Cyperaceae|ligule]] lies at the junction between sheath and blade, preventing water or insects from penetrating into the sheath.<ref name="Cope-2009"/>{{rp|11}}

[[File:Grassbluete numbers clones unlinked.svg|thumb|Inflorecence scheme and floral diagram. 1 – glume, 2 – lemma, 3 – awn, 4 – palea, 5 – lodicules, 6 – stamens, 7 – ovary, 8 – styles.]]

[[Flower]]s of Poaceae are characteristically arranged in [[spikelet]]s, each having one or more florets.<ref name="Cope-2009"/>{{rp|12}} The spikelets are further grouped into [[Raceme|panicles or spikes]]. The part of the spikelet that bears the florets is called the rachilla. A spikelet consists of two (or sometimes fewer) [[bracts]] at the base, called [[glumes]], followed by one or more florets.<ref name="Cope-2009"/>{{rp|13}} A floret consists of the flower surrounded by two bracts, one external—the [[lemma (botany)|lemma]]—and one internal—the [[palea (botany)|palea]]. The flowers are usually [[hermaphroditic]]—[[maize]] being an important exception—and mainly [[anemophily|anemophilous]] or wind-pollinated, although insects occasionally play a role.<ref>{{Cite journal | doi=10.1111/j.1440-6055.1964.tb00625.x|title = Insect Pollination of Grasses|journal = Australian Journal of Entomology| volume=3| pages=74|year = 1964|doi-access=| s2cid=264140616 }}</ref> The [[perianth]] is reduced to two scales, called ''[[lodicule]]s'',<ref name="Cope-2009"/>{{rp|11}} that expand and contract to spread the lemma and palea; these are generally interpreted to be modified sepals. The [[fruit]] of grasses is a [[caryopsis]], in which the seed coat is fused to the fruit wall.<ref name="Cope-2009"/>{{rp|16}}
A [[Tiller (botany)|tiller]] is a leafy shoot other than the first shoot produced from the seed.<ref name="Cope-2009"/>{{rp|11}}

=== Growth and development ===
[[File:Grassflowers.jpg|upright=1.15|thumb|Grass flowers]]
Grass blades grow at the base of the blade and not from elongated stem tips. This low growth point evolved in response to grazing animals and allows grasses to be [[grazing|grazed]] or [[lawnmower|mown]] regularly without severe damage to the plant.<ref name="Attenborough-1984">{{cite book|title=The Living Planet|first=David |last=Attenborough|publisher=[[British Broadcasting Corporation]]|isbn=978-0-563-20207-3|year=1984|author-link=David Attenborough|title-link=The Living Planet }}</ref>{{rp|113–114}}

Three general classifications of growth habit present in grasses: bunch-type (also called caespitose), [[stolon]]iferous, and [[rhizome|rhizomatous]].<ref>{{Cite book|last=Staller|first=John|url=https://books.google.com/books?id=jHL1dry3W_oC&pg=PA131|title=Maize Cobs and Cultures: History of Zea mays L.|date=2009-12-02|publisher=Springer Science & Business Media|isbn=978-3-642-04506-6|language=en}}</ref>
The success of the grasses lies in part in their morphology and growth processes and in part in their physiological diversity. There are both [[C3 carbon fixation|C3]] and [[C4 carbon fixation|C4]] grasses, referring to the photosynthetic pathway for carbon fixation. The C4 grasses have a photosynthetic pathway, linked to specialized [[Kranz anatomy|Kranz leaf anatomy]], which allows for increased [[water use efficiency]], rendering them better adapted to hot, arid environments.<ref>{{Cite book|last=Gibson|first=David J.|url=https://books.google.com/books?id=QZIUDAAAQBAJ|title=Grasses and Grassland Ecology|date=2009|publisher=Oxford University Press|isbn=978-0-19-852918-7|language=en|page=63}}</ref>

The C3 grasses are referred to as "cool-season" grasses, while the C4 plants are considered "warm-season" grasses.<ref name="Cope-2009"/>{{rp|18–19}}
* Annual cool-season – [[wheat]], [[rye]], annual bluegrass (annual meadowgrass, ''[[Poa annua]]''), and [[oat]]
* Perennial cool-season – orchardgrass (cocksfoot, ''[[Dactylis glomerata]]''), fescue (''[[Festuca]]'' spp.), [[Kentucky bluegrass]] and perennial ryegrass (''[[Lolium perenne]]'')
* Annual warm-season – [[maize]], [[sudangrass]], and [[pearl millet]]
* Perennial warm-season – [[big bluestem]], [[Indiangrass]], [[Bermudagrass]] and [[switchgrass]].

Although the C4 species are all in the [[PACMAD clade]] (see diagram below), it seems that various forms of C4 have arisen some twenty or more times, in various subfamilies or genera. In the ''[[Aristida]]'' genus for example, one species (''A. longifolia'') is C3 but the approximately 300 other species are C4. As another example, the whole tribe of [[Andropogoneae]], which includes [[maize]], [[sorghum]], [[sugar cane]], "[[Job's tears]]", and [[bluestem grass]]es, is C4.<ref name="GPWGII-2012"/> Around 46 percent of grass species are C4 plants.<ref>{{Cite book|last=Harris|first=Stephen A.|url=https://books.google.com/books?id=QkedAwAAQBAJ&pg=PT28|title=Grasses|date=2014-04-15|publisher=Reaktion Books|isbn=978-1-78023-313-0|language=en}}</ref>

== Taxonomy ==
The name Poaceae was given by [[John Hendley Barnhart]] in 1895,<ref>{{cite journal |last=Barnhart| first=John Hendley |date=15 January 1895 |title=Family nomenclature|journal=Bulletin of the Torrey Botanical Club |volume=22 |issue=1 |pages=1–24 |url=https://archive.org/details/jstor-2485402 |access-date=5 June 2016 | doi=10.2307/2485402 | jstor=2485402 }}</ref>{{rp|7}} based on the tribe Poeae described in 1814 by [[Robert Brown (Scottish botanist from Montrose)|Robert Brown]], and the type genus ''[[Poa]]'' described in 1753 by [[Carl Linnaeus]]. The term is derived from the Ancient Greek [[Wiktionary:Poa|πόα (póa, "fodder")]].

=== Evolutionary history ===
Grasses include some of the most versatile [[plant life-form]]s. They became widespread toward the end of the [[Cretaceous]] period, and fossilized [[dinosaur]] dung ([[coprolite]]s) belonging to the [[Sauropoda|sauropod]] [[Titanosauria|titanosaurs]] (though this provenance has been questioned)<ref name=":0">{{Cite journal |last1=Khosla |first1=Ashu |last2=Chin |first2=Karen |last3=Verma |first3=Omkar |last4=Lucas |first4=Spencer G. |last5=Hunt |first5=Adrian P. |last6=Xi |first6=Dangpeng |last7=Dutta |first7=Debi |last8=Alimohammadian |first8=Habib |date=2025-03-14 |title=Palaeoenvironmental and palaeoecological inferences from inclusions in vertebrate omnivore coprolites from the Upper Cretaceous Lameta Formation of central India |url=https://linkinghub.elsevier.com/retrieve/pii/S0195667125000333 |journal=Cretaceous Research |volume=172 |language=en |pages=106110 |doi=10.1016/j.cretres.2025.106110|bibcode=2025CrRes.17206110K }}</ref> have been found containing [[phytolith]]s of a variety that include grasses that are related to modern [[rice]] and [[bamboo]].<ref>{{cite journal |title=Dinosaurs Dined on Grass |first1=Dolores R. |last1=Piperno |first2=Hans-Dieter |last2=Sues |journal=[[Science (magazine)|Science]] |date=18 November 2005 |volume=310 |issue=5751 |pages=1126–1128 |doi=10.1126/science.1121020 |pmid=16293745|s2cid=83493897 }}</ref> Grasses have adapted to conditions in lush [[rain forest]]s, dry [[desert]]s, cold mountains and even [[Intertidal ecology|intertidal habitat]]s, and are currently the most widespread plant type; grass is a valuable source of food and energy for all sorts of wildlife.

A cladogram shows subfamilies and approximate species numbers in brackets:<ref name="GPWGII-2012">{{cite journal |author=Grass Phylogeny Working Group II |date=2012 |title=New grass phylogeny resolves deep evolutionary relationships and discovers C<sub>4</sub> origins |journal=New Phytologist |volume=193 |issue=2 |pages=304–312 |doi=10.1111/j.1469-8137.2011.03972.x |pmid=22115274|bibcode=2012NewPh.193..304. |hdl=2262/73271 |hdl-access=free }} {{open access}}</ref>

{{clade|style=font-size:90%;line-height:75%;width:800px;
    |label1=
|1={{clade
  |1={{clade
    |1={{clade
      |1={{clade
      |label1=[[PACMAD clade]]
      |1={{clade
  |1={{clade
       |1={{clade
      |1={{clade
    |1=[[Chloridoideae]] (1600)
    |2=[[Danthonioideae]] (300)
         }}
      |2={{clade
    |1=[[Micrairoideae]] (200)
    |2=[[Arundinoideae]] (50)
         }}
   }}
       |2=[[Panicoideae]] (3250)
     }}
  |2=[[Aristidoideae]] (350)
         }}
      |label2=[[BOP clade]]
      |2={{clade
            |1=[[Oryzoideae]] (110)
            |2={{clade
          |1=[[Bambusoideae]] – bamboos (1450)
          |2=[[Pooideae]] (3850)
        }}
         }}
         }}
      |2=[[Puelioideae]] (11)
       }}
    |2=[[Pharoideae]] (13)
     }}
  |2=[[Anomochlooideae]] (4)
  }}
}}

[[File:Anomochloa.jpg|thumb|Drawing of ''[[Anomochloa marantoidea]]'', one of the most primitive living grass species]]

Before 2005, fossil findings indicated that grasses evolved around 55 million years ago. Finds of grass-like [[phytolith]]s in [[Cretaceous]] dinosaur [[coprolite]]s from the latest Cretaceous ([[Maastrichtian]]) aged [[Lameta Formation]] of India have pushed this date back to 66 million years ago.<ref name="Piperno-2005">{{cite journal
 | last1 = Piperno
 | first1 = Dolores R.
 | last2 = Sues
 | first2 = Hans-Dieter
 | date = 2005
 | title = Dinosaurs Dined on Grass
 | journal = Science
 | volume = 310
 | issue = 5751
 | pages = 1126–8
 | doi = 10.1126/science.1121020
 | pmid = 16293745
| s2cid = 83493897
 }}</ref><ref name="Prasad-2005">{{cite journal
 | last1= Prasad |first1=V. |last2=Stroemberg |first2=C.A.E. |last3=Alimohammadian |first3=H. |last4=Sahni |first4=A.
 | date = 2005
 | title = Dinosaur coprolites and the early evolution of grasses and grazers
 | journal = Science
 | volume = 310
 | issue = 5751
 | pages = 1177–1180
 | doi=10.1126/science.1118806
 | pmid = 16293759
|bibcode=2005Sci...310.1177P |s2cid=1816461 }}</ref> Due to high [[Phosphorus#Nutrition|phosphatic]] content of 12.2-16.2% in Type A coprolites collected from the Lameta, an omnivore is hypothesized to be the source, contradicting the hypothesis of a sauropod origin.<ref name=":0" /> 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.<ref name="Prasad-2011">{{cite journal |last1=Prasad |first1=V. |last2=Strömberg |first2=C.A. |last3=Leaché |first3=A.D. |last4=Samant |first4=B. |last5=Patnaik |first5=R. |last6=Tang |first6=L. |last7=Mohabey |first7=D.M. |last8=Ge |first8=S. |last9=Sahni |first9=A. |date=2011 |title=Late Cretaceous origin of the rice tribe provides evidence for early diversification in Poaceae |journal=Nature Communications |volume=2 |page=480 |doi=10.1038/ncomms1482 |pmid=21934664 |bibcode=2011NatCo...2..480P |doi-access=free }}</ref>

In 2018, a study described grass microfossils extracted from the teeth of the [[Hadrosauroidea|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. These are currently the oldest known grass fossils.<ref name="Yan-2018" />

Fossils of ''Phragmites'' have been found in the Late Cretaceous of North America, particularly in the Maastrichtian aged [[Laramie Formation]].<ref>{{cite web |title=Mount Everts (Cretaceous of the United States) |url=https://paleobiodb.org/classic/basicCollectionSearch?collection_no=35576 |website=PBDB.org}}</ref> 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]]). <ref>{{cite journal |last1=Berry |first1=E. W. |title=The Upper Cretaceous and Eocene floras of South Carolina and Georgia |journal=U.S. Geological Survey Professional Paper |date=1914 |volume=84 |page=11 |doi=10.3133/pp84|bibcode=1914usgs.rept...11B }}</ref>

The relationships among the three subfamilies Bambusoideae, Oryzoideae and Pooideae in the BOP clade have been resolved: Bambusoideae and Pooideae are more closely related to each other than to Oryzoideae.<ref name="Wu-2012">{{cite journal|last1=Wu |first1=Z.Q. |last2=Ge |first2=S. |date=2012 |title=The phylogeny of the BEP clade in grasses revisited: Evidence from the whole-genome sequences of chloroplasts |journal=Molecular Phylogenetics and Evolution|volume=62 |issue=1 |pages=573–578 |doi=10.1016/j.ympev.2011.10.019 |pmid=22093967 |bibcode=2012MolPE..62..573W }}</ref> This separation occurred within the relatively short time span of about 4 million years.

According to [[Lester Charles King]], the spread of grasses in the [[Neogene|Late Cenozoic]] would have changed patterns of [[hillslope evolution]] favouring slopes that are convex upslope and concave downslope and lacking a [[escarpment|free face]] were common. King argued that this was the result of more slowly acting surface wash caused by carpets of grass which in turn would have resulted in relatively more [[downhill creep|soil creep]].<ref name="Twidale-1992">{{Citation
 | last1  = Twidale
 | first1 = C.R.
 |author-link=Charles Rowland Twidale
 | title = King of the plains: Lester King's contributions to geomorphology
 | journal = [[Geomorphology (journal)|Geomorphology]]
 | volume  = 5
 | issue   =6
 | year    = 1992
 | pages   = 491–509
| doi = 10.1016/0169-555X(92)90021-F
 | bibcode = 1992Geomo...5..491T
 }}</ref><ref name="King-1953">{{cite journal |last1=King |first1=L.C. |date=1953 |title=Canons of landscape evolution |journal=Geological Society of America Bulletin |volume=64 |issue=7 |pages=721–752 |doi= 10.1130/0016-7606(1953)64[721:COLE]2.0.CO;2|bibcode=1953GSAB...64..721K }}</ref>

=== Subdivisions ===
There are about 12,000 grass species in about 771 genera that are classified into 12 subfamilies.<ref name="Soreng-2015">{{cite journal |last1=Soreng |first1=Robert J. |last2=Peterson |first2=Paul M. |last3=Romschenko |first3=Konstantin |last4=Davidse |first4=Gerrit |last5=Zuloaga |first5=Fernando O. |last6=Judziewicz |first6=Emmet J. |last7=Filgueiras |first7=Tarciso S. |last8=Davis |first8=Jerrold I. |last9=Morrone |first9=Osvaldo |title=A worldwide phylogenetic classification of the Poaceae (Gramineae) |journal=Journal of Systematics and Evolution |volume=53 |issue=2 |year=2015 |pages=117–137 |issn=1674-4918 |doi=10.1111/jse.12150|bibcode=2015JSyEv..53..117S |s2cid=84052108 |hdl=11336/25248 |hdl-access=free }} {{open access}}</ref> See the full [[list of Poaceae genera]].
* [[Anomochlooideae]] [[Robert Knud Friedrich Pilger|Pilg.]] ex [[Eva Hedwig Ingeborg Potztal|Potztal]], a small lineage of broad-leaved grasses that includes two genera (''Anomochloa'', ''Streptochaeta'')
* [[Pharoideae]] [[Lynn G. Clark|L.G.Clark]] & [[Emmet J. Judziewicz|Judz.]], a small lineage of grasses of three genera, including ''Pharus'' and ''Leptaspis''
* [[Puelioideae]] L.G.Clark, [[Mikio Kobayashi|M.Kobay.]], [[Sarah Mathews|S.Mathews]], [[Russell Edwin Spangler|Spangler]] & [[Elizabeth Anne Kellogg|E.A.Kellogg]], a small lineage of the African genus ''Puelia''
* [[Pooideae]], including [[wheat]], [[barley]], [[oat]]s, brome-grass (''[[Bromus]]''), reed-grasses (''Calamagrostis'') and many lawn and pasture grasses such as [[Bluegrass (grass)|bluegrass]] (''Poa'')
[[File:Setaria verticillata W IMG 1085.jpg|thumb|upright=0.85|''[[Setaria verticillata]]'' from [[Panicoideae]]]]
* [[Bambusoideae]], including [[bamboo]]
* [[Ehrhartoideae]], including [[rice]] and [[wild rice]]
* [[Aristideae|Aristidoideae]], including ''[[Aristida]]''
* [[Arundinoideae]], including [[giant reed]] and [[common reed]]
* [[Chloridoideae]], including the lovegrasses (''Eragrostis'', about 350 species, including [[teff]]), dropseeds (''Sporobolus'', some 160 species), [[finger millet]] (''Eleusine coracana'' (L.) Gaertn.), and the muhly grasses (''Muhlenbergia'', about 175 species)
* [[Panicoideae]], including [[panic grass]], [[maize]], [[sorghum]], [[sugarcane]], most [[millet]]s, [[fonio]], "[[Job's tears]]", and [[bluestem grass]]es
* [[Micrairoideae]]
* [[Danthonioideae]], including [[Cortaderia|pampas grass]]

== Distribution ==
The grass family is one of the most widely distributed and abundant groups of plants on [[Earth]]. Grasses are found on every continent,<ref>{{cite thesis|last=Sarandón|first=Ramiro|title=Biología poblacional del gramon (''Cynodon'' spp., Gramineae)|date=1988|pages=189|publisher=Universidad Nacional de La Plata|url=http://sedici.unlp.edu.ar/handle/10915/4709|access-date=22 April 2014|url-status=live|archive-url=https://web.archive.org/web/20140911233011/http://sedici.unlp.edu.ar/handle/10915/4709|archive-date=11 September 2014|type=Tesis}}</ref><ref name="APWeb-2010">{{cite web|url=http://www.mobot.org/MOBOT/Research/APweb/welcome.html#Famlarge|title=Angiosperm phylogeny website|access-date=2007-10-07|url-status=live|archive-url=https://web.archive.org/web/20100206221914/http://www.mobot.org/mobot/research/apweb/welcome.html#Famlarge|archive-date=2010-02-06}}</ref> including [[Antarctica]]. The Antarctic hair grass, ''[[Deschampsia antarctica]]'' is one of only two flowering plant species native to the western [[Antarctic Peninsula]].<ref>{{cite book |title=Antarctic ecology |date=1984 |publisher=Academic Press |location=London |isbn=978-0-12-439501-5 |page=76 |url=https://archive.org/details/antarcticecology0001unse/page/76}}</ref>

== Ecology ==
[[File:Grasses in the Valles Caldera 2014-06-26.JPG|thumb|upright=1.15|Wind-blown grass in the [[Valles Caldera]] in New Mexico, United States]]
Grasses are the [[Dominance (ecology)|dominant]] vegetation in many habitats, including [[grassland]], [[salt-marsh]], [[reedswamp]] and [[steppes]]. They also occur as a smaller part of the vegetation in almost every other terrestrial habitat.{{citation needed|date=March 2016}}
Grass-dominated [[biome]]s are called grasslands. If only large, contiguous areas of grasslands are counted, these biomes cover 31% of the planet's land.<ref name="TimeLifeBooks-1985-2" /> Grasslands include [[pampas]], [[steppe]]s, and [[prairie]]s.<ref>{{Cite book|url=https://books.google.com/books?id=uY_Y233ROE0C&q=Grasslands+include+pampas%2C+steppes%2C+and+prairies.&pg=PA108|title=The Field Guide to Geology|last=Lambert|first=David|date=2006|publisher=Infobase Publishing|isbn=9781438130057|language=en|url-status=live|archive-url=https://web.archive.org/web/20180110150237/https://books.google.com/books?id=uY_Y233ROE0C&pg=PA108&dq=Grasslands+include+pampas,+steppes,+and+prairies.&hl=en&sa=X&ved=0ahUKEwjbhqj0163VAhUoqVQKHXQBCrMQ6AEINDAF#v=onepage&q=Grasslands%20include%20pampas,%20steppes,%20and%20prairies.&f=false|archive-date=2018-01-10}}</ref>
Grasses provide food to many [[Grazing (behaviour)|grazing]] mammals,<ref>{{Cite book|last=Cheplick|first=G. P.|url=https://books.google.com/books?id=ID9o08AvrIQC&pg=PA1|title=Population Biology of Grasses|date=1998-03-28|publisher=Cambridge University Press|isbn=978-0-521-57205-7|language=en}}</ref> as well as to many species of [[Butterfly|butterflies]] and [[moth]]s.<ref>{{Cite book|last=Common|first=I. F. B.|url=https://books.google.com/books?id=magzbmvdRvQC&pg=PA65|title=Moths of Australia|date=1990|publisher=BRILL|isbn=978-90-04-09227-3|language=en}}</ref><ref>{{Cite book|last=DK|url=https://books.google.com/books?id=hZR8dn7bYIYC&pg=PA28|title=DK Eyewitness Books: Butterfly and Moth: Discover the Enchanting and Secret Life of Butterflies and Moths in Vivid Detail|date=2000-05-31|publisher=Penguin|isbn=978-0-7566-6908-9|language=en}}</ref>
Many types of animals eat grass as their main source of food, and are called ''[[graminivore]]s'' – these include [[cattle]], [[sheep]], [[horse]]s, [[rabbit]]s and many [[invertebrate]]s, such as [[grasshopper]]s and the caterpillars of many [[Satyridae|brown butterflies]]. Grasses are also eaten by [[Omnivore|omnivorous]] or even occasionally by primarily [[Carnivore|carnivorous]] animals.

[[File:Kangur.rudy.drs.jpg|thumb|right|A [[kangaroo]] eating grass]]
Grasses dominate certain [[biome]]s, especially [[Temperate grasslands, savannas, and shrublands|temperate grasslands]], because many species are adapted to grazing and fire.<ref>{{Cite book|last1=Orians|first1=Gordon H.|url=https://books.google.com/books?id=Ve6sKijB5tEC&pg=PA326|title=Life Study Guide: The Science of Biology|last2=Sadava|first2=David E.|last3=Heller|first3=Craig|last4=Purves|first4=William K.|date=2006-12-22|publisher=Macmillan|isbn=978-0-7167-7893-6|language=en}}</ref>

Grasses are unusual in that the [[meristem]] is near the bottom of the plant; hence, grasses can quickly recover from cropping at the top.<ref>{{cite web |url=http://www.farmwest.com/book/export/html/828 |title=Chapter 1: How grasses grow |publisher=Farmwest.com |access-date=2013-08-26 |url-status=live |archive-url=https://web.archive.org/web/20130910022122/http://www.farmwest.com/book/export/html/828 |archive-date=2013-09-10 }}</ref>
The evolution of large grazing animals in the [[Cenozoic]] contributed to the spread of grasses. Without large grazers, fire-cleared areas are quickly colonized by grasses, and with enough rain, tree seedlings. Trees eventually outcompete most grasses. Trampling grazers kill seedling trees but not grasses.<ref name="Attenborough-1984"/>{{rp|137}}

==Sexual reproduction and meiosis==

[[Sexual reproduction]] and [[meiosis]] have been studied in [[rice]], [[maize]], [[wheat]] and [[barley]].<ref name="Wang-2021">{{cite journal |vauthors=Wang Y, van Rengs WM, Zaidan MW, Underwood CJ |title=Meiosis in crops: from genes to genomes |journal=J Exp Bot |volume=72 |issue=18 |pages=6091–6109 |date=September 2021 |pmid=34009331 |pmc=8483783 |doi=10.1093/jxb/erab217 }}</ref> Meiosis research in these crop species is linked to crop improvement, since meiotic [[genetic recombination|recombination]] is an important component of [[plant breeding]].<ref name="Wang-2021"/> Unlike in animals, the specification of both male and female plant [[germline]]s occurs late in development during flowering.  The transition from the [[sporophyte]] phase to the [[gametophyte]] state is initiated by meiotic entry.<ref name="Wang-2021"/>

== Uses ==
Grasses are, in human terms, perhaps the most economically important plant family.<ref>{{Cite book|last=Smith|first=James P.|url=https://books.google.com/books?id=G6wwDwAAQBAJ&pg=PA10|title=Field Guide to Grasses of California|date=2014-09-12|publisher=Univ of California Press|isbn=978-0-520-27568-3|language=en}}</ref> Their economic importance stems from several areas, including food production, industry, and [[lawn]]s. They have been grown as food for [[domesticated animals]] for up to 6,000 years{{citation needed|reason=where did this number come from?|date=March 2022}} and the grains of grasses such as [[wheat]], rice, maize (corn) and [[barley]] have been the most important human [[food crop]]s. Grasses are also used in the manufacture of [[thatching|thatch]], [[paper]], [[fuel]], [[clothing]], [[Building insulation|insulation]], timber for [[fence|fencing]], [[furniture]], [[scaffolding]] and [[construction]] materials, floor [[matting]], [[#Sports turf|sports turf]] and [[basket weaving|baskets]].

{{wide image|GrazingCowsPasture.jpg|1500px|Grazing cattle on a pasture near [[Hradec nad Moravicí]] in [[Czech Silesia]].}}

=== Food production ===
{{see also|Domestication of wheat}}

Of all crops grown, 70% are grasses.<ref name="Time Life Books-1985">{{cite book|title=Grasslands and Tundra|publisher=Time Life Books|year=1985|series=Planet Earth|editor=George Constable|isbn=978-0-8094-4520-2|page=[https://archive.org/details/grasslandstundra00time/page/19 19]|url-access=registration|url=https://archive.org/details/grasslandstundra00time/page/19}}</ref> Agricultural grasses grown for their edible seeds are called ''[[cereal]]s'' or ''[[grain]]s'' (although the latter term, when used agriculturally, refers to both cereals and similar seeds of other plant species, such as [[buckwheat]] and [[legumes]]). Three cereals&mdash;rice, wheat, and maize (corn)&mdash;provide more than half of all calories consumed by humans.<ref name="Raven-1995">{{cite book|title=Understanding Biology|edition=3rd|first1=P.H. |last1=Raven |first2=G.B. |last2=Johnson |page=536|isbn=978-0-697-22213-8|year=1995|editor=Carol J. Mills|publisher=WM C. Brown}}</ref> Cereals constitute the major source of [[carbohydrate]]s for humans and perhaps the major source of protein; these include rice (in [[South Asia|southern]] and [[eastern Asia]]), maize (in [[Central America|Central]] and [[South America]]), and wheat and barley (in [[Europe]], [[northern Asia]] and the [[Americas]]).

[[Sugarcane]] is the major source of [[sugar]] production. Additional food uses of sugarcane include [[sprouting|sprouted grain]], [[Shoot (botany)|shoot]]s, and [[rhizome]]s, and in drink they include [[sugarcane juice]] and [[plant milk]], as well as [[rum]], [[beer]], [[whisky]], and [[Żubrówka|vodka]].

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

[[Lemongrass]] is a grass used as a culinary herb for its citrus-like flavor and scent.

Many species of grass are grown as [[pasture]] for foraging or as [[fodder]] for prescribed [[livestock]] feeds, particularly in the case of [[cattle]], [[horse]]s, 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]]. Straw (and sometimes hay) may also be used as bedding for animals.

An example of a [[sod]]-forming perennial grass used in agriculture is ''[[Thinopyrum intermedium]]''.

=== Industry ===
Grasses are used as raw material for a multitude of purposes, including construction and in the composition of building materials such as [[cob (material)|cob]], for insulation, in the manufacture of paper and board such as [[oriented structural straw board]]. Grass [[fiber]] can be used for making [[Esparto#Esparto paper|paper]], [[biofuel]] production,<ref>{{Cite book|last1=Gupta|first1=Ram B.|url=https://books.google.com/books?id=XMPp_698ot4C&pg=PA61|title=Gasoline, Diesel, and Ethanol Biofuels from Grasses and Plants|last2=Demirbas|first2=Ayhan|date=2010-04-19|publisher=Cambridge University Press|isbn=978-1-139-48906-5|language=en}}</ref> nonwoven fabrics, and as replacement for glass fibers used in reinforced plastics.<ref>{{Cite book|url=https://books.google.com/books?id=gimlCgAAQBAJ&pg=PA202|title=Encyclopedia of Applied Plant Sciences|date=2016-08-27|publisher=Academic Press|isbn=978-0-12-394808-3|language=en}}</ref> [[Bamboo scaffolding]] is able to withstand typhoon-force winds that would break steel scaffolding.<ref name="TimeLifeBooks-1985-2">{{cite book|title=Grasslands and Tundra|publisher=Time Life Books|year=1985|series=Planet Earth|editor=George Constable|isbn=978-0-8094-4520-2|page=[https://archive.org/details/grasslandstundra00time/page/20 20]|url-access=registration|url=https://archive.org/details/grasslandstundra00time/page/20}}</ref> Larger bamboos and ''[[Arundo donax]]'' have stout culms that can be used in a manner similar to timber, ''Arundo'' is used to make reeds for [[woodwind instrument]]s, and bamboo is used for innumerable implements.<ref>{{Cite book|last=Jacobs|first=Surrey W. L.|url=https://books.google.com/books?id=w3YoAQAAIAAJ|title=Grasses of New South Wales|date=2008|publisher=Botany, University of New England|isbn=978-1-921208-22-5|language=en|page=165}}</ref>

''[[Phragmites|''Phragmites australis'']]'' (common reed) is important for [[thatching]] and wall construction of homes in Africa.<ref>{{Cite book|last1=Finlayson|first1=C. Max|url=https://books.google.com/books?id=fsZOCgAAQBAJ&pg=PA36|title=Wetlands and Human Health|last2=Horwitz|first2=Pierre|last3=Weinstein|first3=Philip|date=2015-08-03|publisher=Springer|isbn=978-94-017-9609-5|language=en}}</ref> Grasses are used in [[water treatment]] systems,<ref>{{Cite book|last1=Boller|first1=Beat|url=https://books.google.com/books?id=lMVfkHFjkZUC&pg=PA145|title=Fodder Crops and Amenity Grasses|last2=Posselt|first2=Ulrich K.|last3=Veronesi|first3=Fabio|date=2010-01-14|publisher=Springer Science & Business Media|isbn=978-1-4419-0760-8|language=en}}</ref> in [[wetland conservation]] and [[land reclamation]], and used to lessen the erosional impact of urban storm water runoff.<ref>{{Cite book|last=Naugle|first=David E.|url=https://books.google.com/books?id=Wc4KAQAAQBAJ&pg=PA154|title=Energy Development and Wildlife Conservation in Western North America|date=2012-06-22|publisher=Island Press|isbn=978-1-61091-022-4|language=en}}</ref>

=== Palaeoecological reconstructions ===
[[File:FossilPoaceaePollen.tif|thumb|Processed, fossilised pollen from the family Poaceae. Species unknown]]

[[Pollen]] morphology, particularly in the ''Poaceae'' family, is key to figuring out their evolutionary relationships and [[Paleoecology|how environments have changed over time]].<ref>{{Cite journal |last1=Edwards |first1=Erika J. |last2=Osborne |first2=Colin P. |last3=Strömberg |first3=Caroline A. E. |last4=Smith |first4=Stephen A. |last5=C Grasses Consortium |last6=Bond |first6=William J. |last7=Christin |first7=Pascal-Antoine |last8=Cousins |first8=Asaph B. |last9=Duvall |first9=Melvin R. |last10=Fox |first10=David L. |last11=Freckleton |first11=Robert P. |last12=Ghannoum |first12=Oula |last13=Hartwell |first13=James |last14=Huang |first14=Yongsong |last15=Janis |first15=Christine M. |date=2010-04-30 |title=The Origins of C 4 Grasslands: Integrating Evolutionary and Ecosystem Science |url=https://www.science.org/doi/10.1126/science.1177216 |journal=Science |language=en |volume=328 |issue=5978 |pages=587–591 |doi=10.1126/science.1177216 |pmid=20431008 |s2cid=17934192 |issn=0036-8075}}</ref> Grass pollen grains, however, often look the same, making it hard to use them for detailed climate or environmental reconstructions.<ref name="Wei-2023">{{Cite journal |last1=Wei |first1=Caixia |last2=Jardine |first2=Phillip E. |last3=Gosling |first3=William D. |last4=Hoorn |first4=Carina |date=2023-01-01 |title=Is Poaceae pollen size a useful proxy in palaeoecological studies? New insights from a Poaceae pollen morphological study in the Amazon |url=https://www.sciencedirect.com/science/article/pii/S0034666722001889 |journal=Review of Palaeobotany and Palynology |volume=308 |pages=104790 |doi=10.1016/j.revpalbo.2022.104790 |bibcode=2023RPaPa.30804790W |issn=0034-6667}}</ref><ref name="Scoble-2024">{{Cite journal |last1=Scoble |first1=Laura |last2=Ussher |first2=Simon J. |last3=Fitzsimons |first3=Mark F. |last4=Ansell |first4=Lauren |last5=Craven |first5=Matthew |last6=Fyfe |first6=Ralph M. |date=2024-02-01 |title=Optimisation of classification methods to differentiate morphologically-similar pollen grains from FT-IR spectra |journal=Review of Palaeobotany and Palynology |volume=321 |pages=105041 |doi=10.1016/j.revpalbo.2023.105041 |bibcode=2024RPaPa.32105041S |issn=0034-6667|doi-access=free }}</ref> Grass pollen has a [[Monocotyledon reproduction|single pore]] and can vary a lot in size, from about 20 to over 100 micrometers, and this size difference has been looked into for clues about past habitats, to tell apart [[domesticated]] grasses from wild ones,<ref>{{Cite journal |last1=Salgado-Labouriau |first1=M. L. |last2=Rinaldi |first2=M. |date=January 1990 |title=Palynology of gramineae of the venezuelan mountains |url=http://www.tandfonline.com/doi/abs/10.1080/00173139009427742 |journal=Grana |language=en |volume=29 |issue=2 |pages=119–128 |doi=10.1080/00173139009427742 |bibcode=1990Grana..29..119S |issn=0017-3134}}</ref><ref>{{Cite journal |last=Beug |first=Hans-Jürgen |title=Leitfaden der Pollenbestimmung für Mitteleuropa und angrenzende Gebiete |url=https://cir.nii.ac.jp/crid/1130000798237605760 |journal=(No Title)|date=1961 }}</ref><ref>{{Cite journal |last1=Holst |first1=Irene |last2=Moreno |first2=J. Enrique |last3=Piperno |first3=Dolores R. |date=2007-11-06 |title=Identification of teosinte, maize, and Tripsacum in Mesoamerica by using pollen, starch grains, and phytoliths |journal=Proceedings of the National Academy of Sciences |language=en |volume=104 |issue=45 |pages=17608–17613 |doi=10.1073/pnas.0708736104 |doi-access=free |issn=0027-8424 |pmc=2077075 |pmid=17978176|bibcode=2007PNAS..10417608H }}</ref> and to indicate various biological features like how they perform [[photosynthesis]],<ref name="Jan-2015">{{Cite journal |last1=Jan |first1=Farooq |last2=Schüler |first2=Lisa |last3=Behling |first3=Hermann |date=2015-04-03 |title=Trends of pollen grain size variation in C3 and C4 Poaceae species using pollen morphology for future assessment of grassland ecosystem dynamics |url=http://www.tandfonline.com/doi/abs/10.1080/00173134.2014.966754 |journal=Grana |language=en |volume=54 |issue=2 |pages=129–145 |doi=10.1080/00173134.2014.966754 |bibcode=2015Grana..54..129J |s2cid=84086503 |issn=0017-3134}}</ref> their breeding systems,<ref name="Jan-2015"/><ref>{{Cite journal |last1=Katsiotis |first1=A. |last2=Hanneman |first2=R. E. |last3=Forsberg |first3=R. A. |date=1995-11-01 |title=Endosperm Balance Number and the polar-nuclei activation hypotheses for endosperm development in interspecific crosses of Solanaceae and Gramineae, respectively |url=https://doi.org/10.1007/BF00223891 |journal=Theoretical and Applied Genetics |language=en |volume=91 |issue=6 |pages=848–855 |doi=10.1007/BF00223891 |pmid=24169968 |s2cid=21178634 |issn=1432-2242}}</ref> and genetic complexity.<ref>{{Cite journal |last1=Radaeski |first1=Jefferson Nunes |last2=Cunha |first2=Djulhan Jacques da |last3=Bauermann |first3=Soraia Girardi |date=2020-07-02 |title=Understanding ecosystem dynamics of herbaceous grasslands (Campos) and arboreal forests (Bambuseae) using Poaceae pollen grains in the Coastal Plains Holocene sediments of Southern Brazil |url=https://www.tandfonline.com/doi/full/10.1080/01916122.2019.1631225 |journal=Palynology |language=en |volume=44 |issue=3 |pages=433–440 |doi=10.1080/01916122.2019.1631225 |bibcode=2020Paly...44..433R |s2cid=199104436 |issn=0191-6122}}</ref><ref>{{Cite journal |last1=Radaeski |first1=Jefferson N. |last2=Bauermann |first2=Soraia G. |last3=Pereira |first3=Antonio B. |date=2016 |title=Poaceae Pollen from Southern Brazil: Distinguishing Grasslands (Campos) from Forests by Analyzing a Diverse Range of Poaceae Species |journal=Frontiers in Plant Science |volume=7 |page=1833 |doi=10.3389/fpls.2016.01833 |doi-access=free |pmid=27999585 |pmc=5138494 |bibcode=2016FrPS....7.1833R |issn=1664-462X}}</ref><ref name="Wei-2023"/> Yet, there's ongoing debate about how effective pollen size is for piecing together historical landscapes and weather patterns, considering other factors such as genetic material amount might also affect pollen size.<ref>{{Cite journal |last1=Knight |first1=Charles A. |last2=Clancy |first2=Rachel B. |last3=Götzenberger |first3=Lars |last4=Dann |first4=Leighton |last5=Beaulieu |first5=Jeremy M. |date=2010-06-09 |title=On the Relationship between Pollen Size and Genome Size |journal=Journal of Botany |language=en |volume=2010 |pages=1–7 |doi=10.1155/2010/612017 |doi-access=free |issn=2090-0120}}</ref><ref>{{Cite journal |last1=den Nijs |first1=Joannes Cornelius Maria |last2=Hooghiemstra |first2=H. |last3=Schalk |first3=P.H. |date=1980 |title=Biosystematic studies of the Rumex acetosella complex (Polygonaceae). IV. Pollen morphology and the possibilities of identification of cytotypes in pollen analysis |url=https://scholar.google.com/scholar_lookup?title=Biosystematic%20studies%20of%20the%20Rumex%20acetosella%20complex%20.%20IV.%20Pollen%20morphology%20and%20the%20possibilities%20of%20identification%20of%20cytotypes%20in%20pollen%20analysis&publication_year=1980&author=J.C.M.%20Den%20Nijs&author=H.%20Hooghiemstra&author=P.H.%20Schalk#d=gs_cit&t=1707502809399&u=%2Fscholar%3Fq%3Dinfo%3AL5RHCvs8e6MJ%3Ascholar.google.com%2F%26output%3Dcite%26scirp%3D0%26hl%3Den |journal=Phyton: Annales Rei Botanicae}}</ref><ref name="Wei-2023"/> Despite these challenges, new techniques in [[Fourier-transform infrared spectroscopy|Fourier-Transform Infrared Spectroscopy]] (FT-IR) and improved statistical methods are now helping to better identify these similar-looking pollen types.<ref name="Scoble-2024"/>

=== Lawn and ornamental use ===
{{Main|Lawn|Ornamental grass}}
[[File:South Lawn.jpg|thumb|A lawn in front of a building]]
Grasses are the primary plants used in lawns, which themselves derive from grazed [[grassland]]s in Europe.{{citation needed|date=March 2016}} They also provide an important means of erosion control (e.g. along roadsides), especially on sloping land.{{citation needed|date=March 2016}} Grass lawns are an important covering of playing surfaces in many sports, including [[football (soccer)]], [[American football]], [[tennis]], [[golf]], [[cricket]], [[softball]] and [[baseball]].

Ornamental grasses, such as [[perennial]] [[bunch grass]]es, are used in many styles of [[garden design]] for their foliage, inflorescences and seed heads. They are often used in [[natural landscaping]], [[xeriscaping]] and slope and beach stabilization in contemporary landscaping, [[wildlife garden]]ing, and [[native plant gardening]].{{citation needed|date=March 2016}} They are used as screens and hedges.<ref>{{Cite book|last=Holmes|first=Roger|url=https://books.google.com/books?id=-ahtILDf2C8C&pg=PA1|title=Taylor's Guide to Ornamental Grasses|date=1997|publisher=Houghton Mifflin Harcourt|isbn=978-0-395-79761-7|language=en}}</ref>

=== Sports turf ===
{{see also|Turf management|Sand-based athletic fields}}
Grass playing fields, courses and pitches are the traditional playing surfaces for many [[sports]], including [[American football]], [[association football]], [[baseball]], [[cricket]], [[golf]], and [[Rugby football|rugby]]. Grass surfaces are also sometimes used for [[horse racing]] and [[tennis]]. Type of maintenance and species of grass used may be important factors for some sports, less critical for others. In some sports facilities, including indoor domes and other places where maintenance of a grass field would be difficult, grass may be replaced with [[artificial turf]], a synthetic grass-like substitute.<ref>{{Cite web|url=https://usatoday30.usatoday.com/sports/football/nfl/patriots/2006-11-14-testaverde-turf_x.htm|title=Pats sign Testaverde; Gillette Stadium's grass field replaced with Field Turf - USATODAY.com|website=usatoday30.usatoday.com|access-date=2019-12-10|archive-date=2021-03-08|archive-url=https://web.archive.org/web/20210308132244/https://usatoday30.usatoday.com/sports/football/nfl/patriots/2006-11-14-testaverde-turf_x.htm|url-status=live}}</ref>

==== Cricket ====
[[File:Australia vs India.jpg|thumb|The gray area is the [[cricket]] pitch currently in use. Parallel to it are other pitches in various states of preparation which could be used in other matches.]]
{{main|Cricket pitch#Preparation and maintenance of the playing area}}
In cricket, the pitch is the strip of carefully mowed and rolled grass where the bowler bowls. 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.<ref>{{cite web|last1=Tainton|first1=Neil|last2=van Deventer|first2=Pietr|title=Cricket pitches Principles and practice of pitch preparation|url=http://static.espncricinfo.com/db/ABOUT_CRICKET/PITCHES/PREP_OF_PITCHES.html#ANCHOR2|website=cricinfo|url-status=live|archive-url=https://web.archive.org/web/20170609100639/http://static.espncricinfo.com/db/ABOUT_CRICKET/PITCHES/PREP_OF_PITCHES.html#ANCHOR2|archive-date=2017-06-09}}</ref>

==== Golf ====
{{main|Golf course}}
Grass on golf courses is kept in three distinct conditions: that of the ''rough'', the ''fairway'', and the ''putting green''. Grass on the fairway is mown short and even, allowing the player to strike the ball cleanly. Playing from the rough is a disadvantage because the long grass may affect the flight of the ball. Grass on the putting green is the shortest and most even, ideally allowing the ball to roll smoothly over the surface. An entire industry revolves around the development and marketing of turf grass varieties.<ref>{{Cite book|last1=Stier|first1=John C.|url=https://books.google.com/books?id=UnnQDwAAQBAJ&pg=PA64|title=Turfgrass: Biology, Use, and Management|last2=Horgan|first2=Brian P.|last3=Bonos|first3=Stacy A.|date=2020-01-22|publisher=John Wiley & Sons|isbn=978-0-89118-613-7|language=en}}</ref>

==== Tennis ====
{{main|Grass court}}
In tennis, grass is grown on very hard-packed soil, and the bounce of a [[tennis ball]] may vary depending on the grass's health, how recently it has been mowed, and the wear and tear of recent play.{{citation needed|date=March 2016}} The surface is softer than [[hard courts]] and [[Clay court|clay]] (other tennis surfaces), so the ball bounces lower, and players must reach the ball faster resulting in a different style of play which may suit some players more than others.{{citation needed|date=March 2016}} Among the world's most prestigious court for grass tennis is Centre Court at [[Wimbledon, London]], which hosts the final of the annual [[Wimbledon Championships]] in England, one of the four [[Grand Slam (tennis)|Grand Slam]] tournaments.

=== Economically important grasses ===
{| cellspacing="24"
|- valign=top
|
;[[Grain|Grain crops]]
* [[Barley]]
* [[Maize]] (corn)
* [[Oat]]s
* [[Rice]]
* [[Rye]]
* [[Sorghum]]
* [[Wheat]]
* [[Millet]]
|
;Leaf and stem crops
* [[Bamboo]]
* [[Marram grass]]
* [[Poa|Meadow-grass]]
* [[Phragmites|Reeds]]
* [[Ryegrass]]
* [[Sugarcane]]
|
;[[Lawn|Lawn grasses]]
* [[Bahiagrass]]
* [[Agrostis|Bentgrass]]
* [[Cynodon|Bermudagrass]]
* [[Poa|Bluegrass]]
* [[Buffalograss]]
* [[Centipede grass]]
* [[Festuca|Fescue]]
* [[Ryegrass]]
* [[St. Augustine grass]]
* ''[[Zoysia]]''
|
;[[Ornamental grass]]es ([[Horticulture|Horticultural]])
* ''[[Calamagrostis]]'' spp.
* ''[[Cortaderia]]'' spp.
* ''[[Deschampsia]]'' spp.
* ''[[Festuca]]'' spp.
* ''[[Melica]]'' spp.
* ''[[Muhlenbergia]]'' spp.
* ''[[Stipa]]'' spp.
|
;[[Model organism]]s
* ''[[Brachypodium distachyon]]''
* Maize (corn)
* Rice
* Sorghum
* Wheat
|}

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.<ref>{{Cite book|last1=Tiner|first1=Ralph W.|url=https://books.google.com/books?id=BHwZBwAAQBAJ&pg=PA491|title=Remote Sensing of Wetlands: Applications and Advances|last2=Lang|first2=Megan W.|last3=Klemas|first3=Victor V.|date=2015-03-23|publisher=CRC Press|isbn=978-1-4822-3738-2|language=en}}</ref><ref>{{Cite book|last=Vymazal|first=Jan|url=https://books.google.com/books?id=bgTZ-DQZ7CEC&pg=PA134|title=Water and Nutrient Management in Natural and Constructed Wetlands|date=2010-09-23|publisher=Springer Science & Business Media|isbn=978-90-481-9585-5|language=en}}</ref>


== Role in society ==
[[File:Grass covered house in Iceland 1972.jpg|thumb|Grass-covered house in [[Iceland]]]]
[[File:Grass Blades.jpg|thumb|Typical grass seen in meadows]]
[[File:Grass with flowers.png|thumb|Grass with non-grass flowers around it]]
Grasses have long had significance in human society. They have been cultivated as feed for people and [[domesticated animals]] for thousands of years. The primary ingredient of [[beer]] is usually barley or wheat, each of which has been used for this purpose for over 4,000 years.<ref>{{Cite book|last1=Mudgil|first1=Deepak|url=https://books.google.com/books?id=3Q2NDwAAQBAJ&pg=PA81|title=Beverages : Processing and Technology|last2=Barak|first2=Sheweta|date=2018-06-01|publisher=Scientific Publishers|isbn=978-93-87991-72-9|language=en}}</ref>

In some places, particularly in [[suburb]]an areas, the maintenance of a grass lawn is a sign of a homeowner's responsibility to the overall appearance of their neighborhood. One work credits lawn maintenance to:

{{blockquote|...the desire for upward mobility and its manifestation in the lawn. 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.<ref>Matthew J. Lindstrom, Hugh Bartling, ''Suburban sprawl: culture, theory, and politics'' (2003), p. 72, quoting Virginia Scott Jenkins, ''The Lawn: A History of an American Obsession'' (1994), p. 21.</ref><ref>{{cite journal
| first1 = Paul | last1= Robbins
| first2=Julie T. | last2=Sharp
| title= Producing and Consuming Chemicals: The Moral Economy of the American Lawn
| journal=Economic Geography
|volume=79 | number=4 | year=2003
|pages = 425–451 | jstor=30032947
| publisher= Taylor Francis
| doi= 10.1111/j.1944-8287.2003.tb00222.x
| s2cid= 218771233
}} Reprinted in {{Cite book|editor1=William G. Moseley
|url=https://books.google.com/books?id=nTnImTKlJIgC&dq=%2522Producing+and+Consuming+Chemicals:+The+Moral+Economy+of+the+American+Lawn%2522&pg=PA323|title=The Introductory Reader in Human Geography: Contemporary Debates and Classic Writings
|editor2=David A. Lanegran
|editor3=Kavita Pandit
|date=2007-05-14|publisher=Wiley-Blackwell
|isbn=978-1-4051-4921-1|language=en|access-date=2023-02-23|archive-date=2023-02-23|archive-url=https://web.archive.org/web/20230223041437/https://books.google.com/books?id=nTnImTKlJIgC&pg=PA323&dq=%2522Producing+and+Consuming+Chemicals:+The+Moral+Economy+of+the+American+Lawn%2522|url-status=live}}</ref>}}

In communities with [[drought]] problems, watering of lawns may be [[outdoor water-use restriction|restricted]] to certain times of day or days of the week.<ref>{{cite web |url=http://www.metrovancouver.org/services/water/conservation/Pages/sprinkling.aspx |title=Lawn Sprinkling Regulations in Metro Vancouver, BC, Canada |publisher=Metrovancouver.org |date=2011-02-21 |access-date=2013-08-26 |url-status=dead |archive-url=https://web.archive.org/web/20120119054412/http://www.metrovancouver.org/services/water/conservation/Pages/sprinkling.aspx |archive-date=2012-01-19 }}</ref> Many US municipalities and homeowners' associations have rules that require lawns to be maintained to certain specifications, sanctioning those who allow the grass to grow too long.<ref>{{Cite web|title=Lawn Maintenance and Climate Change|url=https://psci.princeton.edu/tips/2020/5/11/law-maintenance-and-climate-change|access-date=2021-10-28|website=PSCI|date=12 May 2020 |language=en-US|archive-date=2021-10-28|archive-url=https://web.archive.org/web/20211028103914/https://psci.princeton.edu/tips/2020/5/11/law-maintenance-and-climate-change|url-status=live}}</ref><ref>{{Cite book|last1=Gillman|first1=Jeff|url=https://books.google.com/books?id=c54__9Z0jSEC&pg=PA189|title=How the Government Got in Your Backyard: Superweeds, Frankenfoods, Lawn Wars, and the (nonpartisan) Truth about Environmental Policies|last2=Heberlig|first2=Eric S.|date=2011-01-01|publisher=Timber Press|isbn=978-1-60469-001-9|language=en}}</ref>

The [[smell of freshly cut grass]] is produced mainly by [[cis-3-Hexenal]].<ref>{{cite web|url=http://www.chm.bris.ac.uk/motm/hexenal/hexenalh.htm|title=hexenal|publisher=School of Chemistry, University of Bristol|access-date=2013-08-26|url-status=live|archive-url=https://web.archive.org/web/20131009234826/http://www.chm.bris.ac.uk/motm/hexenal/hexenalh.htm|archive-date=2013-10-09}}</ref>

Some common [[aphorism]]s involve grass. For example:
* "The grass is always greener on the other side" suggests an alternate state of affairs will always seem preferable to one's own.
* "Don't let the grass grow under your feet" tells someone to get moving.
* "A [[snake]] in the grass" means dangers that are hidden.
* "When [[elephant]]s fight, it is the grass that suffers" tells of bystanders caught in the crossfire.
A folk myth about grass is that it refuses to grow where any violent death has occurred.<ref>Olmert, Michael (1996). ''Milton's Teeth and Ovid's Umbrella: Curiouser & Curiouser Adventures in History'', p. 208. Simon & Schuster, New York. {{ISBN|0-684-80164-7}}.</ref>

== Image gallery ==
<gallery mode=packed>
File:Gräsfrön - Grass seeds - 2025.jpg|Grass seeds, a mixture of 90% [[Festuca rubra]] and 10% [[Festuca ovina]].
File:Ruwbeemdgras Poa trivialis ligula.jpg|Leaves of ''[[Poa trivialis]]'' showing the [[ligule]]s
File:Bamboo DSCN2465.jpg|Bamboo stem and leaves, nodes are evident
File:Chasmanthium latifolium-spikelet.jpg|A ''[[Chasmanthium latifolium]]'' spikelet
File:En Spica spiculae.png|Wheat spike and spikelet
File:En Aperta.png|Spikelet opened to show caryopsis
File:Harestail grass.jpg|[[Harestail grass]]
File:Grass.jpg|Grass
File:Saccharum-officinarum2.JPG|Sugarcane (''[[Saccharum officinarum]]'')
File:Bromus hordeaceus unten.jpeg|Roots of ''[[Bromus hordeaceus]]''
File:Ohra.jpg|Barley mature spikes (''[[Hordeum vulgare]]'')
File:Koeh-283.jpg|Illustration depicting both staminate and pistillate flowers of maize (''[[Zea mays]]'')
File:Flowering Grass.JPG|A grass flower head (meadow foxtail) showing the plain-coloured flowers with large anthers
File:Grass Anthers.JPG|Anthers detached from a meadow foxtail flower
File:Setaria verticillata W IMG 1084.jpg|''[[Setaria verticillata]]'', bristly foxtail
File:Setaria verticillata W IMG 1083.jpg|''[[Setaria verticillata]]'', bristly foxtail
File:Oryza sativa in Kadavoor.jpg|''[[Oryza sativa]]'', [[Kerala]], [[India]]
</gallery>

== See also ==
* [[Agrostology]]
* [[Forb]]
* [[GrassBase]]
* [[Green track]]
* [[PACMAD clade]]
* ''[[Thinopyrum intermedium]]''

== References ==
{{Reflist|30em}}

== External links ==
{{Commons category multi|Poaceae|Grass}}
{{Wikispecies}}
{{Wiktionary|grass}}
* [http://dictionary.reference.com/browse/grass Need a Definition of Grass?]
* [http://www.brerc.eclipse.co.uk/files/brerc_grass_key.pdf Vegetative Key to Grasses]
* [http://www.theplantlist.org/browse/A/Poaceae/ Poaceae] at [http://www.theplantlist.org/ ''The Plant List'']
* [https://keyapa.com/sp/learn-about-grasses/ Learn about grasses] at [https://keyapa.com/sp/ ''The Story of the Poaceae'']
* {{cite EB9 |wstitle = Grasses |volume= XI | pages=53-60 |short=1 }}
* [http://delta-intkey.com/angio/www/graminea.htm Gramineae] {{Webarchive|url=https://web.archive.org/web/20070103200438/http://delta-intkey.com/angio/ |date=2007-01-03 }} at [http://delta-intkey.com/angio/ ''The Families of Flowering Plants (DELTA)''] {{Webarchive|url=https://web.archive.org/web/20070103200438/http://delta-intkey.com/ |date=2007-01-03 }}
* [http://www.mobot.org/mobot/research/apweb/orders/poalesweb.htm#Poaceae Poaceae] at the [http://www.mobot.org/mobot/research/apweb/ ''Angiosperm Phylogeny Website'']
* [http://www.tropicos.org/projectwebportal.aspx?pagename=ClassificationNWG&projectid=10 ''Poaceae Classification''] from the online [http://www.tropicos.org/Project/CNWG ''Catalogue of New World Grasses'']
* [http://greif.uni-greifswald.de/floragreif/?flora_search=Taxon&action=genus&fam=Poaceae Poaceae] {{Webarchive|url=https://web.archive.org/web/20160402212821/http://greif.uni-greifswald.de/floragreif/?action=genus&fam=poaceae&flora_search=taxon |date=2016-04-02 }} at the online [http://greif.uni-greifswald.de/floragreif/ ''Guide to the Flora of Mongolia''] {{Webarchive|url=https://web.archive.org/web/20130129202437/http://greif.uni-greifswald.de/floragreif/ |date=2013-01-29 }}
* [http://www.efloras.org/flora_page.aspx?flora_id=1050 Poaceae] at the online [http://www.efloras.org/flora_page.aspx?flora_id=100 ''Flora of Taiwan'']
* [http://www.efloras.org/florataxon.aspx?flora_id=5&taxon_id=10711 Poaceae] at the online [http://www.efloras.org/flora_page.aspx?flora_id=5 ''Flora of Pakistan'']
* [http://www.zimbabweflora.co.zw/speciesdata/family.php?family_id=177 Poaceae] at the online [http://www.zimbabweflora.co.zw/index.php ''Flora of Zimbabwe'']
* [http://florabase.dec.wa.gov.au/browse/profile/22751 Poaceae] {{Webarchive|url=https://web.archive.org/web/20120401053908/http://florabase.dec.wa.gov.au/browse/profile/22751 |date=2012-04-01 }} at the online [http://florabase.dec.wa.gov.au/ ''Flora of Western Australia'']
* Grasses of Australia (AusGrass2) – [http://ausgrass2.myspecies.info/ AusGrass2 | Grasses of Australia]
* [http://floraseries.landcareresearch.co.nz/pages/Taxa.aspx?id=_8ae81d6d-1dca-418b-8bcf-4b6e1e5a2f6d&fileName=Flora%205.xml Gramineae] {{Webarchive|url=https://web.archive.org/web/20200807131329/http://floraseries.landcareresearch.co.nz/pages/Taxa.aspx?id=_8ae81d6d-1dca-418b-8bcf-4b6e1e5a2f6d&fileName=Flora%205.xml |date=2020-08-07 }} at the online [http://floraseries.landcareresearch.co.nz/pages/index.aspx ''Flora of New Zealand''] {{Webarchive|url=https://wayback.archive-it.org/all/20170525032751/http://floraseries.landcareresearch.co.nz/pages/index.aspx |date=2017-05-25 }}
* [http://www.landcareresearch.co.nz/research/biosystematics/plants/grasskey/ NZ Grass Key] {{Webarchive|url=https://web.archive.org/web/20120511110941/http://landcareresearch.co.nz/research/biosystematics/plants/grasskey/ |date=2012-05-11 }} An Interactive Key to New Zealand Grasses at [http://www.landcareresearch.co.nz/ ''Landcare Research'']
* [http://delta-intkey.com/grass/ The Grass Genera of the World] {{Webarchive|url=https://web.archive.org/web/20061007035015/http://delta-intkey.com/grass/ |date=2006-10-07 }} at [http://delta-intkey.com/ ''DELTA intkey''] {{Webarchive|url=https://web.archive.org/web/20070103200438/http://delta-intkey.com/ |date=2007-01-03 }}
* [http://www.rbgkew.org.uk/data/grasses-db/sppindex.htm ''RGB Kew - The Online World Grass Flora''] {{Webarchive|url=https://web.archive.org/web/20090224215113/http://www.rbgkew.org.uk/data/grasses-db/sppindex.htm |date=2009-02-24 }}
* [http://grassworld.myspecies.info/ ''GrassWorld'']

{{Cereals}}
{{Angiosperm families}}
{{Poaceae-navbox}}
{{Taxonbar|from=Q43238}}
{{Authority control}}

[[Category:Poaceae| ]]
[[Category:Grasses| ]]
[[Category:Extant Albian first appearances]]
[[Category:Grasslands]]
[[Category:Plant life-forms]]
[[Category:Plants by habit]]
[[Category:Poales families]]