関: spicula、spicule

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small pointed structure serving as a skeletal element in various marine and freshwater invertebrates e.g. sponges and corals (同)spiculum

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針状のもの / (海綿などの)針骨,針片,(植物の)小穂(すい)状花　交接針

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2014/11/23 20:05:05」(JST)

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The Poaceae (also called Gramineae or true grasses) are a large and nearly ubiquitous family of monocotyledonous flowering plants. With more than 10,000 domesticated and wild species, the Poaceae represent the fifth-largest plant family, following the Asteraceae, Orchidaceae, Fabaceae, and Rubiaceae.^[3] Though commonly called "grasses", seagrasses, rushes, and sedges fall outside this family. The rushes and sedges are related to the Poaceae, being members of the order Poales, but the seagrasses are members of order Alismatales.

Grasslands are estimated to compose 20% of the vegetation cover of the Earth. Poaceae live in many other habitats, including wetlands, forests, and tundra.

Domestication of poaceous cereal crops such as maize (corn), wheat, rice, barley, and millet lies at the foundation of sedentary living and civilization around the world, and the Poaceae still constitute the most economically important plant family in modern times, providing forage, building materials (bamboo, thatch) and fuel (ethanol), as well as food.

Description

Diagram of a typical lawn grass plant.

Grasses generally have the following characteristics (the image gallery can be used for reference):

Poaceae have hollow stems called culms plugged at intervals by solid leaf-bearing nodes. Grass leaves are nearly always alternate and distichous (in one plane), and have parallel veins. Each leaf is differentiated into a lower sheath hugging the stem and a blade with entire (i.e., smooth) margins. The leaf blades of many grasses are hardened with silica phytoliths, which discourage grazing animals; some, such as sword grass, are sharp enough to cut human skin. A membranous appendage or fringe of hairs called the ligule lies at the junction between sheath and blade, preventing water or insects from penetrating into the sheath.

Parts of a spikelet

Flowers of Poaceae are characteristically arranged in spikelets, each spikelet having one or more florets. The spikelets are further grouped into panicles or spikes. A spikelet consists of two (or sometimes fewer) bracts at the base, called glumes, followed by one or more florets. A floret consists of the flower surrounded by two bracts, one external—the lemma—and one internal—the palea. The flowers are usually hermaphroditic—maize being an important exception—and anemophilous or wind-pollinated. The perianth is reduced to two scales, called lodicules, that expand and contract to spread the lemma and palea; these are generally interpreted to be modified sepals. This complex structure can be seen in the image on the right, portraying a wheat (Triticum aestivum) spikelet.

The fruit of Poaceae is a caryopsis, in which the seed coat is fused to the fruit wall.

A tiller is a leafy shoot other than the first shoot produced from the seed.

Grass flowers

Growth and development

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 grazed or mown regularly without severe damage to the plant.^[4]

Three general classifications of growth habit present in grasses: bunch-type (also called caespitose), stoloniferous, and rhizomatous.

The success of the grasses lies in part in their morphology and growth processes, and in part in their physiological diversity. Most of the grasses divide into two physiological groups, using the C3 and C4 photosynthetic pathways for carbon fixation. 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 and those lacking in carbon dioxide.

The C3 grasses are referred to as "cool-season" grasses, while the C4 plants are considered "warm-season" grasses; they may be either annual or perennial.

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.

Ecology

Grass-dominated biomes are called grasslands. If only large, contiguous areas of grasslands are counted, these biomes cover 31% of the planet's land.^[5] Grasslands include pampas, steppes, and prairies.

Grasses provide food to many grazing mammals—such as livestock, deer, and elephants—as well as to many species of butterflies and moths.

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 shade out and kill most grasses. Trampling grazers kill seedling trees but not grasses.^[6]

Evolution

Until recently, fossil findings indicated that grasses evolved around 55 million years ago. Recent findings of grass-like phytoliths in Cretaceous dinosaur coprolites have pushed this date back to 66 million years ago.^[1]^[7] Indeed, revised dating of the origins of the rice tribe Oryzeae suggest a date as early as 107 to 129 Mya.^[8]

The relationships among the subfamilies Bambusoideae, Ehrhartoideae and Pooideae in the BEP clade have been resolved: Bambusoideae and Pooideae are more closely related to each other than to Ehrhartoideae.^[9] This separation occurred within a relatively short time span (about 4 million years).

Distribution

The grass family is one of the most widely distributed and abundant groups of plants on Earth. Grasses are found on every continent,^[10] and are absent only from central Greenland and much of Antarctica.^[11]

Taxonomy

Setaria verticillata from Panicoideae

Tragus roxburghii from Chloridoideae

Recent classifications of the grass family^[12] recognize 12 subfamilies and a small number of taxa with uncertain placements:

Anomochlooideae Potztal, a small lineage of broad-leaved grasses that includes two genera (Anomochloa, Streptochaeta)
Pharoideae L.G.Clark & Judz., a small lineage of grasses of three genera, including Pharus and Leptaspis
Puelioideae L.G.Clark, M.Kobay., S.Mathews, Spangler & E.A.Kellogg, a small lineage of the African genus Puelia
Pooideae, including wheat, barley, oats, brome-grass (Bromus), reed-grasses (Calamagrostis) and many lawn and pasture grasses
Bambusoideae, including bamboo
Ehrhartoideae, including rice and wild rice
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 millets, fonio, and bluestem grasses
Micrairoideae
Danthonioideae, including pampas grass

Depending on the classification followed, the family includes around 668 genera.^[3]

Etymology

The Poaceae name was given by John Hendley Barnhart in 1895,^[13] based on the tribe Poeae (described in 1814 by Robert Brown), and the type genus Poa (described in 1753 by Linnaeus). The term is derived from the Ancient Greek term for grass.

Uses

Grasses are, in human terms, perhaps the most economically important plant family. Grasses' economic importance stems from several areas, including food production, industry, and lawns.

Food production

Agricultural grasses grown for their edible seeds are called cereals or grains (although the latter term, agriculturally, refers to both cereals and legumes). Three cereals – rice, wheat, and maize (corn) – provide more than half of all calories eaten by humans.^[14] Of all crops, 70% are grasses.^[15] Cereals constitute the major source of carbohydrates for humans and perhaps the major source of protein, and include rice in southern and eastern Asia, maize in Central and South America, and wheat and barley in Europe, northern Asia and the Americas.

Sugarcane is the major source of sugar production. Many other grasses are grown for forage and fodder for animal feed, particularly for sheep and cattle, thereby indirectly providing more human calories.

Industry

Grasses are used for construction. Scaffolding made from bamboo is able to withstand typhoon-force winds that would break steel scaffolding.^[5] Larger bamboos and Arundo donax have stout culms that can be used in a manner similar to timber, and grass roots stabilize the sod of sod houses. Arundo is used to make reeds for woodwind instruments, and bamboo is used for innumerable implements.

Grass fiber can be used for making paper, and for biofuel production.

Phragmites australis (common reed) is important in water treatment, wetland habitat preservation and land reclamation in Afro-Eurasia.

Lawn and ornamental grasses

Grasses are the primary plant used in lawns, which themselves derive from grazed grasslands in Europe. They also provide an important means of erosion control (e.g., along roadsides), especially on sloping land.

Although supplanted by artificial turf in some games, grasses are still an important covering of playing surfaces in many sports, including football (soccer), tennis, golf, cricket, softball and baseball.

Ornamental grasses, such as perennial bunch grasses, are used in many styles of garden design for their foliage, inflorescences, seed heads, and slope stabilization. They are often used in natural landscaping, xeriscaping, contemporary or modern landscaping, wildlife gardening, and native plant gardening.

Economically important grasses

Grain crops

Barley
Maize (corn)
Oats
Rice
Rye
Sorghum
Wheat
Millet

Leaf and stem crops

Bamboo
Marram grass
Meadow-grass
Reeds
Ryegrass
Sugarcane

Lawn grasses

Bahia grass
Bent grass
Bermuda grass
Buffalograss
Centipede grass
Fescue
Meadow-grass
Ryegrass
St. Augustine grass
Zoysia

Ornamental grasses (Horticultural)

Calamagrostis spp.
Cortaderia spp.
Deschampsia spp.
Festuca spp.
Melica spp.
Muhlenbergia spp.
Stipa spp.

Model organisms

Brachypodium distachyon
Maize (corn)
Rice
Sorghum
Wheat

Grasses and society

Grass-covered house in Iceland

Grasses have long had significance in human society. They have been cultivated as feed for domesticated animals for up to 10,000 years, and have been used to make paper since the second century AD.^{[citation needed]} Also, the primary ingredient of beer is usually barley or wheat, both of which have been used for this purpose for over 4,000 years.^{[citation needed]}

Some common aphorisms 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 elephants fight, it is the grass which 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.^[16]

Genera

See the full list of Poaceae genera.

Image gallery

Leaves of Poa trivialis showing the ligules
Bamboo stem and leaves, nodes are evident
A Chasmanthium latifolium spikelet
Wheat spike and spikelet
Spikelet opened to show caryopsis
Harestail grass
Grass
Sugarcane (Saccharum officinarum)
Roots of Bromus hordeaceus
Barley mature spikes (Hordeum vulgare)
Illustration depicting both staminate and pistillate flowers of maize (Zea mays)
A grass flower head (meadow foxtail) showing the plain-coloured flowers with large anthers.
Anthers detached from a meadow foxtail flower
Setaria verticillata, bristly foxtail
Setaria verticillata, bristly foxtail
Oryza sativa, Kerala, India

References

^ ^a ^b Piperno, D. R.; Sues, H.D. (2005). "Dinosaurs Dined on Grass". Science 310 (5751): 1126hor = Piperno, D.R. doi:10.1126/science.1121020. PMID 16293745. Cite uses deprecated parameters (help)
^ Angiosperm Phylogeny Group (2009). "An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG III" (PDF). Botanical Journal of the Linnean Society 161 (2): 105–121. doi:10.1111/j.1095-8339.2009.00996.x. Retrieved 2013-06-26.
^ ^a ^b Stevens, P.F. "Angiosperm Phylogeny Website". Retrieved 2007-10-07.
^ David Attenborough (1984). The Living Planet. British Broadcasting Corporation. pp. 113–4. ISBN 0-563-20207-6.
^ ^a ^b George Constable (ed), ed. (1985). Grasslands and Tundra. Planet Earth. Time Life Books. p. 20. ISBN 0-8094-4520-4.
^ David Attenborough (1984). The Living Planet. British Broadcasting Corporation. p. 137.
^ Prasad, V.; Stroemberg, C.A.E.; Alimohammadian, H.; Sahni, A. (2005). "Dinosaur Coprolites and the Early Evolution of Grasses and Grazers". Science(Washington) 310 (5751): 1177–1180. doi:10.1126/science.1118806. PMID 16293759. Cite uses deprecated parameters (help)
^ Prasad V, Strömberg CA, Leaché AD, Samant B, Patnaik R, Tang L, Mohabey DM, Ge S, Sahni A. (2011). Late Cretaceous origin of the rice tribe provides evidence for early diversification in Poaceae. Nat Commun. 2:480. doi:10.1038/ncomms1482 PMID 21934664
^ Wu ZQ, Ge S (2011) The phylogeny of the BEP clade in grasses revisited: Evidence from the whole-genome sequences of chloroplasts. Mol Phylogenet Evol
^ Sarandón, Ramiro (1988). "Biología poblacional del gramon (Cynodon spp., gramineae)". p. 189. Retrieved 22 April 2014.
^ "Angiosperm phylogeny website". Retrieved 2007-10-07.
^ "Catalogue of New World Grasses". Retrieved 2012-03-01.
^ Barnhart, J.H. (1895) Poaceae. Bulletin of the Torrey Botanical Club 22: 7.
^ Peter H. Raven & George B. Johnson (1995). Carol J. Mills (ed), ed. Understanding Biology (3rd ed.). WM C. Brown. p. 536. ISBN 0-697-22213-6.
^ George Constable (ed), ed. (1985). Grasslands and Tundra. Planet Earth. Time Life Books. p. 19. ISBN 0-8094-4520-4.
^ 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.

External links

Wikimedia Commons has media related to Poaceae.

Wikispecies has information related to: Poaceae

Poaceae at The Plant List
Gramineae at The Families of Flowering Plants (DELTA)
Poaceae at the Encyclopedia of Life
Poaceae at the Angiosperm Phylogeny Website
Poaceae Classification from the online Catalogue of New World Grasses
Poaceae at the online Flora of China
Poaceae at the online Guide to the Flora of Mongolia
Poaceae at the online Flora of Taiwan
Poaceae at the online Flora of Pakistan
Poaceae at the online Flora of Zimbabwe
Poaceae at the online Flora of Western Australia
Grasses of Australia (AusGrass2) - http://ausgrass2.myspecies.info/
Gramineae at the online Flora of New Zealand
NZ Grass Key An Interactive Key to New Zealand Grasses at Landcare Research
The Grass Genera of the World at DELTA intkey
GrassBase - The Online World Grass Flora at the Royal Botanic Gardens - Kew
GrassWorld - http://grassworld.myspecies.info/

English Journal

Host finding behaviour of the coconut mite Aceria guerreronis.

Melo JW1, Lima DB, Sabelis MW, Pallini A, Gondim MG Jr.
Experimental & applied acarology.Exp Appl Acarol.2014 Dec;64(4):445-54. doi: 10.1007/s10493-014-9834-7. Epub 2014 Jul 18.
For the coconut mite, Aceria guerreronis Keifer, its host plant, the coconut palm, is not merely a source of food, but more generally a habitat to live in for several generations. For these minute organisms, finding a new plant is difficult and risky, especially because their main mode of dispersal
PMID 25033768

Genetic mechanisms underlying yield potential in the rice high-yielding cultivar Takanari, based on reciprocal chromosome segment substitution lines.

Takai T, Ikka T, Kondo K, Nonoue Y, Ono N, Arai-Sanoh Y, Yoshinaga S, Nakano H, Yano M, Kondo M, Yamamoto T.
BMC plant biology.BMC Plant Biol.2014 Nov 18;14(1):295. [Epub ahead of print]
BackgroundIncreasing rice yield potential is a major objective in rice breeding programs, given the need for meeting the demands of population growth, especially in Asia. Genetic analysis using genomic information and high-yielding cultivars can facilitate understanding of the genetic mechanisms und
PMID 25404368

FRIZZY PANICLE drives supernumerary spikelets in bread wheat (T. aestivum L.).

Dobrovolskaya O1, Pont C2, Sibout R3, Martinek P4, Badaeva E5, Murat F2, Chosson A2, Watanabe N6, Prat E7, Gautier N7, Gautier V2, Poncet C2, Orlov Y1, Krasnikov A8, Berges H7, Salina E1, Laikova L1, Salse J9.
Plant physiology.Plant Physiol.2014 Nov 14. pii: pp.114.250043. [Epub ahead of print]
Bread wheat inflorescences, or spikes, are characteristically unbranched and normally bear one spikelet per rachis node. Wheat mutants on which supernumerary spikelets (SS) develop are particularly useful resources for work towards understanding the genetic mechanisms underlying wheat inflorescence
PMID 25398545

Japanese Journal

地上部窒素吸収量の増大による水稲多収品種の籾数増加とその限界

小林英和,千葉雅大,長田健二
日本作物学会紀事 83(4), 374-379, 2014-10
NAID 40020297720

イネ黄化萎縮病発生圃場に認められた水稲の奇形穂の形態と圃場内分布

白土宏之,大平陽一
日本作物学会紀事 83(2), 165-172, 2014-04
NAID 40020293728

穂肥施用のための幼穂形成期の生育診断によるコシヒカリの籾数推定

佐藤徹,東聡志,金井政人 [他]
北陸作物学会報 (49), 51-53, 2014
NAID 40020101809

Related Pictures

★リンクテーブル★

リンク元

「小穂」

Poaceae (true grasses); Temporal range: Late Cretaceous - recent, 66–0Ma 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
	Subfamilies; Anomochlooideae; Aristidoideae; Arundinoideae; Bambusoideae; Chloridoideae; Danthonioideae; Ehrhartoideae; Micrairoideae; Panicoideae; Pharoideae; Pooideae; Puelioideae

　　[★]

英: spicule、spicula、spikelet
関: 骨片

[DinosDined-1] Piperno, D. R.; Sues, H.D. (2005). "Dinosaurs Dined on Grass". Science 310 (5751): 1126hor = Piperno, D.R. doi:10.1126/science.1121020. PMID 16293745. Cite uses deprecated parameters (help)

[APGIII2009-2] Angiosperm Phylogeny Group (2009). "An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG III" (PDF). Botanical Journal of the Linnean Society 161 (2): 105–121. doi:10.1111/j.1095-8339.2009.00996.x. Retrieved 2013-06-26.

[Missouri_botanical_garden-3] Stevens, P.F. "Angiosperm Phylogeny Website". Retrieved 2007-10-07.

[Attenborough_113-4-4] David Attenborough (1984). The Living Planet. British Broadcasting Corporation. pp. 113–4. ISBN 0-563-20207-6.

[Time_life_20-5] George Constable (ed), ed. (1985). Grasslands and Tundra. Planet Earth. Time Life Books. p. 20. ISBN 0-8094-4520-4.

[Attenborough_137-6] David Attenborough (1984). The Living Planet. British Broadcasting Corporation. p. 137.

[Prasad2005-7] Prasad, V.; Stroemberg, C.A.E.; Alimohammadian, H.; Sahni, A. (2005). "Dinosaur Coprolites and the Early Evolution of Grasses and Grazers". Science(Washington) 310 (5751): 1177–1180. doi:10.1126/science.1118806. PMID 16293759. Cite uses deprecated parameters (help)

[8] Prasad V, Strömberg CA, Leaché AD, Samant B, Patnaik R, Tang L, Mohabey DM, Ge S, Sahni A. (2011). Late Cretaceous origin of the rice tribe provides evidence for early diversification in Poaceae. Nat Commun. 2:480. doi:10.1038/ncomms1482 PMID 21934664

[9] Wu ZQ, Ge S (2011) The phylogeny of the BEP clade in grasses revisited: Evidence from the whole-genome sequences of chloroplasts. Mol Phylogenet Evol

[10] Sarandón, Ramiro (1988). "Biología poblacional del gramon (Cynodon spp., gramineae)". p. 189. Retrieved 22 April 2014.

[Missouri_Botanical_Garden-11] "Angiosperm phylogeny website". Retrieved 2007-10-07.

[Tropicos-12] "Catalogue of New World Grasses". Retrieved 2012-03-01.

[13] Barnhart, J.H. (1895) Poaceae. Bulletin of the Torrey Botanical Club 22: 7.

[Raven_and_Johnson-14] Peter H. Raven & George B. Johnson (1995). Carol J. Mills (ed), ed. Understanding Biology (3rd ed.). WM C. Brown. p. 536. ISBN 0-697-22213-6.

[Time_life_19-15] George Constable (ed), ed. (1985). Grasslands and Tundra. Planet Earth. Time Life Books. p. 19. ISBN 0-8094-4520-4.

[16] 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.

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