1. Family: Poaceae Barnhart
    1. Genus: Poa L.
      1. Poa pratensis L.

        This species is accepted, and its native range is Subarctic to Temp. Northern Hemisphere to N. Mexico.

    [GB]
    Habit
    Perennial; caespitose. Rhizomes elongated. Culms erect, or geniculately ascending; 10-90 cm long; 2-4 -noded. Culm-internodes terete; smooth. Lateral branches lacking. Leaves mostly basal. Leaf-sheaths keeled; smooth. Ligule an eciliate membrane; 1-3 mm long; truncate. Leaf-blades 5-30 cm long; 2-4 mm wide. Leaf-blade surface smooth, or scaberulous; glabrous, or pubescent (rarely); sparsely hairy. Leaf-blade margins scaberulous. Leaf-blade apex abruptly acute; hooded.
    Inflorescences
    Inflorescence a panicle. Panicle open, or contracted; oblong, or pyramidal, or ovate; dense, or loose; 2-20 cm long; 1-12 cm wide. Primary panicle branches ascending, or spreading; 3-5 -nate. Panicle branches flexuous; scaberulous. Spikelets solitary. Fertile spikelets pedicelled. Pedicels 0.2-2 mm long.
    Spikelets
    Spikelets comprising 2-5 fertile florets; with diminished florets at the apex. Spikelets oblong, or ovate; laterally compressed; 4-6 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes obscured by lemmas; smooth. Floret callus woolly.
    Fertile
    Spikelets comprising 2-5 fertile florets; with diminished florets at the apex. Spikelets oblong, or ovate; laterally compressed; 4-6 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes obscured by lemmas; smooth. Floret callus woolly.
    Glume
    Glumes persistent; similar; shorter than spikelet. Lower glume ovate; 2-3.5 mm long; 0.8 length of upper glume; membranous; 1-keeled; 1(-3) -veined. Lower glume primary vein scabrous. Lower glume lateral veins absent, or obscure. Lower glume apex acute. Upper glume elliptic, or ovate; 2.5-4 mm long; 0.9-1 length of adjacent fertile lemma; membranous; 1-keeled; 3 -veined. Upper glume primary vein scabrous. Upper glume apex acute.
    Florets
    Fertile lemma ovate; oblong in profile; 3-4 mm long; membranous; much thinner above; much thinner on margins; keeled; 5 -veined. Lemma midvein scabrous; ciliate; hairy below. Lemma lateral veins distinct; stopping well short of apex. Lemma surface granulose. Lemma margins ciliate; hairy below. Lemma apex acute. Palea 1 length of lemma. Palea keels scabrous. Apical sterile florets resembling fertile though underdeveloped.
    Flowers
    Lodicules 2; membranous. Anthers 3; 1.5-2 mm long.
    Fruits
    Caryopsis with adherent pericarp. Hilum punctiform.
    Distribution
    Europe: northern, central, southwestern, southeastern, and eastern. Africa: north, Macaronesia, south, and middle Atlantic ocean. Asia-temperate: Siberia, Soviet far east, Soviet Middle Asia, Caucasus, western Asia, China, Mongolia, and eastern Asia. Asia-tropical: India, Malesia, and Papuasia. Australasia: Australia and New Zealand. Pacific: north-central. North America: Subarctic, western Canada, eastern Canada, northwest USA, north-central USA, northeast USA, southwest USA, south-central USA, southeast USA, and Mexico. South America: Mesoamericana, Caribbean, western South America, Brazil, and southern South America. Antarctic: Subantarctic islands.
    Reference
    Poeae. CEH.

    Images

    Distribution

    Native to:

    Afghanistan, Alabama, Alaska, Albania, Alberta, Altay, Amur, Arizona, Arkansas, Austria, Baltic States, Belarus, Belgium, British Columbia, Bulgaria, Buryatiya, California, Central European Rus, China North-Central, China South-Central, China Southeast, Chita, Colorado, Connecticut, Corse, Cyprus, Czechoslovakia, Delaware, Denmark, District of Columbia, East Aegean Is., East European Russia, East Himalaya, Finland, Florida, France, Føroyar, Georgia, Germany, Great Britain, Greece, Greenland, Hungary, Iceland, Idaho, Illinois, Indiana, Inner Mongolia, Iowa, Iran, Iraq, Ireland, Irkutsk, Italy, Jawa, Kamchatka, Kansas, Kazakhstan, Kentucky, Khabarovsk, Kirgizstan, Korea, Krasnoyarsk, Kriti, Krym, Kuril Is., Labrador, Lebanon-Syria, Louisiana, Magadan, Maine, Manchuria, Manitoba, Maryland, Masachusettes, Mexico Northeast, Mexico Northwest, Michigan, Minnesota, Mississippi, Missouri, Mongolia, Montana, Myanmar, Nebraska, Nepal, Netherlands, Nevada, New Brunswick, New Guinea, New Hampshire, New Jersey, New Mexico, New York, Newfoundland, North Carolina, North Caucasus, North Dakota, North European Russi, Northwest European R, Northwest Territorie, Norway, Nova Scotia, Nunavut, Ohio, Oklahoma, Ontario, Oregon, Pakistan, Palestine, Pennsylvania, Philippines, Poland, Portugal, Primorye, Prince Edward I., Qinghai, Québec, Rhode I., Romania, Sakhalin, Sardegna, Saskatchewan, Sicilia, South Carolina, South Dakota, South European Russi, Spain, Svalbard, Sweden, Switzerland, Tadzhikistan, Tennessee, Texas, Tibet, Transcaucasus, Turkey, Turkey-in-Europe, Turkmenistan, Tuva, Ukraine, Utah, Uzbekistan, Vermont, Virginia, Washington, West Himalaya, West Siberia, West Virginia, Wisconsin, Wyoming, Xinjiang, Yakutskiya, Yemen, Yugoslavia, Yukon

    Introduced into:

    Aleutian Is., Algeria, Amsterdam-St.Paul Is, Antipodean Is., Argentina Northeast, Argentina Northwest, Argentina South, Azores, Bermuda, Bolivia, Brazil South, Canary Is., Cape Provinces, Chatham Is., Chile Central, Chile North, Chile South, Costa Rica, Crozet Is., Dominican Republic, Ecuador, Falkland Is., Free State, Haiti, Hawaii, Jamaica, Japan, Kerguelen, KwaZulu-Natal, Lesotho, Madeira, Marion-Prince Edward, Mexico Central, Mexico Gulf, Mexico Southwest, Morocco, New South Wales, New Zealand North, New Zealand South, Norfolk Is., Northern Provinces, Peru, Puerto Rico, Réunion, South Australia, South Georgia, Sri Lanka, St.Helena, Taiwan, Tasmania, Tristan da Cunha, Uruguay, Victoria, Western Australia

    Poa pratensis L. appears in other Kew resources:

    Date Reference Identified As Barcode Type Status
    Jan 1, 2010 Hooker, J.D. [s.n.], Sikkim K000789641 isotype
    Jan 1, 2010 Hooker, J.D. [s.n.], Sikkim K000789640 isotype
    Aug 2, 1985 Kirk, T. [42], New Zealand K000641387 lectotype
    s.coll. [103], Great Britain K000641180
    s.coll. [107], Great Britain K000641181
    s.coll. [101], Great Britain K000641182
    s.coll. [109], Great Britain K000641183
    s.coll. [105], Great Britain K000641184
    s.coll. [111], Great Britain K000641185
    Hohenacker, R.F. [s.n.], Iran K000641310
    Merrill, E.D. [4712], Philippines K000290458 isotype
    Alexeenko, T. [3044], Tajikistan K000789557 isotype
    Nyárády, E.I. [1171], Romania K000641187
    Nyárády, E.I. [728], Romania K000641188
    Laínz [s.n.], Spain K000641189
    Sysrejtschikow, D. [2832], Latvia K000641186
    Hartmann, H. [2380], Jammu-Kashmir K000789642 isotype
    Ovchinnikov [1371], Tajikistan K000789558
    Pohle, R. [s.n.], Russian Federation K000789559 Unknown type material

    First published in Sp. Pl.: 67 (1753)

    Accepted by

    • Bosser, J. & Renvoize, S.A. (2018). Flore des Mascareignes 203: 1-276. IRD Éditions, MSIRI, RBG-Kew, Paris.
    • Bernal, R., Gradstein, R.S. & Celis, M. (eds.) (2016). Catálogo de plantas y líquenes de Colombia 1-2: 1-3068. Libro impreso.
    • Kavousi, M., Assadi, M. & Nejadsattari, T. (2015). Taxonomic revision of the genus Poa L. in Iran, new additions to Flora Iranica, and a new identification key Turkish Journal of Botany 39: 105-127.
    • Chang, C.S., Kim, H. & Chang, K.S. (2014). Provisional checklist of vascular plants for the Korea peninsula flora (KPF): 1-660. DESIGNPOST.
    • Kuo, M.L. (ed.) (2012). Flora of Taiwan, ed. 2, Suppl.: 1-414. Editorial Committee of the Flora of Taiwan, Second Edition, National Taiwan University.
    • Acevedo-Rodríguez, P. & Strong, M.T. (2012). Catalogue of seed plants of the West Indies Smithsonian Contributions to Botany 98: 1-1192.
    • Giraldo-Cañas, D. (2011). Catálogo de la familia Poaceae en Colombia Darwiniana 49: 139-247.
    • Meyer, F.K. (2011). Beiträge zur Flora von Albanien Haussknechtia, Beih. 15: 1-220.
    • Edgar, E & Connor, H.E. (2010). Flora of New Zealand, ed. 2, 5: 1-650. R.E.Owen, Government Printer, Wellington.
    • Dobignard, D. & Chatelain, C. (2010). Index synonymique de la flore d'Afrique du nord 1: 1-455. Éditions des conservatoire et jardin botaniques, Genève.
    • Clayton, W.D. & Snow, N. (2010). A key to Pacific Grasses: 1-107. Kew Publishing, Royal Botanic Gardens, Kew.
    • Wilson, A. (ed.) (2009). Flora of Australia 44A: 1-410. Australian Government Publishing Service, Canberra.
    • Kandwal, M.K. & Gupta, B.K. (2009). An update on grass flora of Uttarkhand Indian Journal of Forestry 32: 657-668.
    • Gremmen, N. & Halbertsma, R.L. (2009). Alien plants and their impact on Tristan da Cunha 2: 1-307. Overseas Territories Environment Programme (OTEP).
    • Zuloaga, F.O., Morrone, O. , Belgrano, M.J., Marticorena, C. & Marchesi, E. (eds.) (2008). Catálogo de las Plantas Vasculares del Cono Sur Monographs in Systematic Botany from the Missouri Botanical Garden 107: 1-3348.
    • Grubov, V.I. (2008). Key to the vascular plants of Mongolia (with an atlas) 2: 1-503. Academy of Sciences, Mongolian People's Republic, Ulaan Bator.
    • Flora of North America Editorial Committee (2007). Flora of North America North of Mexico 24: 1-908. Oxford University Press, New York, Oxford.
    • Wu, Z. & Raven, P.H. (eds.) (2006). Poaceae Flora of China 22: 1-733. Missouri Botanical Garden Press, St. Louis.
    • Clayton, W.D., Harman, K.T. & Williamson, H. (2006). World Grass Species - Synonymy database The Board of Trustees of the Royal Botanic Gardens, Kew.
    • Dávila, P., Mejia-Saulés, M.T., Gómez-Sánchez, N., Valdés-Reyna, J., Ortíz, J.J., Morín, C., Castrejón, J. & Ocampo, A. (2006). Catálogo de las Gramíneas de México: 1-671. CONABIO, México city.
    • Takhtajan, A.L. (ed.) (2006). Conspectus Florae Caucasi 2: 1-466. Editio Universitatis Petropolitanae.
    • Frenot, Y., Chown, S.L., Whinam, J., Selkirk, P.M., Convey, P., Skotnicki, M. & Bergstrom,D.M. (2005). Biological invasions in the Antarctic: extent, impacts and implications Biological Reviews of the Cambridge Philosophical Society 80: 45-72.
    • Germishuizen, G. & Meyer, N.L. (eds.) (2003). Plants of Southern Africa: an annotated checklist. Strelitzia 14.: i-vi, 1-1231. National Botanical Institute, Pretoria.
    • Malyschev, L.I. & Peschkova, G.A. (eds.) (2001). Flora of Siberia 2: 1-362. Scientific Publishers, Inc., Enfield, Plymouth.
    • Noltie, H.J. (2000). Flora of Bhutan 3(2): 457-883. Royal Botanic Gardens, Edinburgh.
    • Press, J.R. et al. (2000). Annotated Checklist of the Flowering Plants of Nepal: i-x, 1-430. Natural History Museum, London.
    • Fedorov, A.A. (ed.) (1999). Flora of Russia. The European part and bordering regions 1: 1-546. A.A. Balkema, Rotterdam, Broekfield.
    • Jørgensen, P.M. & León-Yánez, S. (eds.) (1999). Catalogue of the Vascular Plants of Ecuador Monographs in Systematic Botany from the Missouri Botanical Garden 75: i-viii, 1-1181.
    • Renvoize, S.A. (1998). Gramineas de Bolivia: 1-644. The Royal Botanic Gardens, Kew.
    • Wood, J.R.I. (1997). A Handbook of the Yemen Flora: 1-434. The Board of Trustees of the Royal Botanic Gardens, Kew.
    • Lee, W.T. (1996). Lineamenta Florae Koreae: 1-1688. Soul T'ukpyolsi: Ak'ademi Sojok.
    • Davidse, G. & al. (eds.) (1994). Flora Mesoamericana 6: 1-543. Universidad Nacional Autónoma de México, México, D.F.
    • Orchard, A.E. (ed.) (1994). Oceanic Islands 1 Flora of Australia 49: 1-681. Australian Government Publishing Service, Canberra.
    • Dassanayake (ed.) (1994). A Revised Handbook to the Flora of Ceylon 8: 1-458. Oxford & IBH Publishing Co. PVT. LTD., New Delhi, Calcutta.
    • Brako, L. & Zarucchi, J.L. (1993). Catalogue of the Flowering Plants and Gymnosperms of Peru Monographs in Systematic Botany from the Missouri Botanical Garden 45: i-xl, 1-1286.
    • Karthikeyan, S., Jain, S.K., Nayar, M.P. & Sanjappa, M. (1989). Florae Indicae Enumeratio: Monocotyledonae: 1-435. Botanical Survey of India, Calcutta.
    • Koyama, T. (1987). Grasses of Japan and its neighboring regions: an identification manual: 1-570. Kodansha, Tokyo, Japan.
    • Davis, P.H. (ed.) (1985). Flora of Turkey and the East Aegean Islands 9: 1-724. Edinburgh University Press, Edinburgh.
    • Kharkevich, S.S., Probatova, N.S. & Novikov, V.S. (1985). Sosudistye rasteniia sovetskogo Dal’nego Vostoka 1: 1-383. Izd-vo "Nauka," Leningradskoe otd-nie, Leningrad.
    • Meikle, R.D. (1985). Flora of Cyprus 2: 833-1970. The Bentham-Moxon Trust Royal Botanic Gardens, Kew.
    • Cope, T.A. (1982). Flora of Pakistan 143: 1-678. Department of Botany, University of Karachi, Karachi.
    • Tutin, T.G. & al. (eds.) (1980). Flora Europaea 5: 1-452. Cambridge University Press.
    • Bor, N.L. (1970). Flora Iranica 70: 1-573. Naturhistorisches Museums Wien.
    • Bor, N.L. (1968). Flora of Iraq 9: 1-588. Ministry of Agriculture & Agrarian Reform, Baghdad.

    Literature

    Kew Backbone Distributions
    • Bosser, J. & Renvoize, S.A. (2018). Flore des Mascareignes 203: 1-276. IRD Éditions, MSIRI, RBG-Kew, Paris.
    • Kuo, M.L. (ed.) (2012). Flora of Taiwan, ed. 2, Suppl.: 1-414. Editorial Committee of the Flora of Taiwan, Second Edition, National Taiwan University.
    • Soreng, R.J. & Peterson, P.M. (2012). Revision of Poa L. (Poaceae, Pooideae, Poeae, Poinae) in Mexico: new records, re-evaluation of P. ruprechtii, and two new species, P. palmeri and P. wendtii PhytoKeys 15: 1-104.
    • Acevedo-Rodríguez, P. & Strong, M.T. (2012). Catalogue of seed plants of the West Indies Smithsonian Contributions to Botany 98: 1-1192.
    • Marhold, K. (ed.) (2012). IAPT/IOPB chromosome data 14 Taxon 61: 1336-1345.
    • Shaulo, D.N., Myakshina, T.A., Shaulo, S.P. & Ernst, A.S. (2011). Floristic findings in the upper Yenisei basin Turczaninowia 14(3): 100-105.
    • Sheremetova, S.A., Ebel, A.L. & Buko, T.E. (2011). Supplement to the flora of Kemerovo region since 2001 till 2010 Turczaninowia 14(1): 65-74.
    • Edgar, E & Connor, H.E. (2010). Flora of New Zealand, ed. 2, 5: 1-650. R.E.Owen, Government Printer, Wellington.
    • Dobignard, D. & Chatelain, C. (2010). Index synonymique de la flore d'Afrique du nord 1: 1-455. Éditions des conservatoire et jardin botaniques, Genève.
    • Chilton, L. (2010). Plant list for Lesvos, slightly revised 1998-2009: 1-36. Marengo, Hunstanton, England.
    • Wilson, A. (ed.) (2009). Flora of Australia 44A: 1-410. Australian Government Publishing Service, Canberra.
    • Kandwal, M.K. & Gupta, B.K. (2009). An update on grass flora of Uttarkhand Indian Journal of Forestry 32: 657-668.
    • Gremmen, N. & Halbertsma, R.L. (2009). Alien plants and their impact on Tristan da Cunha 2: 1-307. Overseas Territories Environment Programme (OTEP).
    • Zuloaga, F.O., Morrone, O. , Belgrano, M.J., Marticorena, C. & Marchesi, E. (eds.) (2008). Catálogo de las Plantas Vasculares del Cono Sur Monographs in Systematic Botany from the Missouri Botanical Garden 107: 1-3348.
    • Grubov, V.I. (2008). Key to the vascular plants of Mongolia (with an atlas) 2: 1-503. Academy of Sciences, Mongolian People's Republic, Ulaan Bator.
    • Flora of North America Editorial Committee (2007). Flora of North America North of Mexico 24: 1-908. Oxford University Press, New York, Oxford.
    • Wu, Z. & Raven, P.H. (eds.) (2006). Poaceae Flora of China 22: 1-733. Missouri Botanical Garden Press, St. Louis.
    • Dávila, P., Mejia-Saulés, M.T., Gómez-Sánchez, N., Valdés-Reyna, J., Ortíz, J.J., Morín, C., Castrejón, J. & Ocampo, A. (2006). Catálogo de las Gramíneas de México: 1-671. CONABIO, México city.
    • Takhtajan, A.L. (ed.) (2006). Conspectus Florae Caucasi 2: 1-466. Editio Universitatis Petropolitanae.
    • Frenot, Y., Chown, S.L., Whinam, J., Selkirk, P.M., Convey, P., Skotnicki, M. & Bergstrom,D.M. (2005). Biological invasions in the Antarctic: extent, impacts and implications Biological Reviews of the Cambridge Philosophical Society 80: 45-72.
    • Germishuizen, G. & Meyer, N.L. (eds.) (2003). Plants of Southern Africa: an annotated checklist. Strelitzia 14.: i-vi, 1-1231. National Botanical Institute, Pretoria.
    • Broughton, D.A. & McAdam, J.H. (2002). The non-native vascular flora of the Falkland islands Botanical Journal of Scotland 54: 153-190.
    • Malyschev, L.I. & Peschkova, G.A. (eds.) (2001). Flora of Siberia 2: 1-362. Scientific Publishers, Inc., Enfield, Plymouth.
    • Noltie, H.J. (2000). Flora of Bhutan 3(2): 457-883. Royal Botanic Gardens, Edinburgh.
    • Press, J.R. et al. (2000). Annotated Checklist of the Flowering Plants of Nepal: i-x, 1-430. Natural History Museum, London.
    • Fedorov, A.A. (ed.) (1999). Flora of Russia. The European part and bordering regions 1: 1-546. A.A. Balkema, Rotterdam, Broekfield.
    • Jørgensen, P.M. & León-Yánez, S. (eds.) (1999). Catalogue of the Vascular Plants of Ecuador Monographs in Systematic Botany from the Missouri Botanical Garden 75: i-viii, 1-1181.
    • Renvoize, S.A. (1998). Gramineas de Bolivia: 1-644. The Royal Botanic Gardens, Kew.
    • Wood, J.R.I. (1997). A Handbook of the Yemen Flora: 1-434. The Board of Trustees of the Royal Botanic Gardens, Kew.
    • Lee, W.T. (1996). Lineamenta Florae Koreae: 1-1688. Soul T'ukpyolsi: Ak'ademi Sojok.
    • Davidse, G. & al. (eds.) (1994). Flora Mesoamericana 6: 1-543. Universidad Nacional Autónoma de México, México, D.F.
    • Orchard, A.E. (ed.) (1994). Oceanic Islands 1 Flora of Australia 49: 1-681. Australian Government Publishing Service, Canberra.
    • Dassanayake (ed.) (1994). A Revised Handbook to the Flora of Ceylon 8: 1-458. Oxford & IBH Publishing Co. PVT. LTD., New Delhi, Calcutta.
    • Brako, L. & Zarucchi, J.L. (1993). Catalogue of the Flowering Plants and Gymnosperms of Peru Monographs in Systematic Botany from the Missouri Botanical Garden 45: i-xl, 1-1286.
    • Koyama, T. (1987). Grasses of Japan and its neighboring regions: an identification manual: 1-570. Kodansha, Tokyo, Japan.
    • Davis, P.H. (ed.) (1985). Flora of Turkey and the East Aegean Islands 9: 1-724. Edinburgh University Press, Edinburgh.
    • Kharkevich, S.S., Probatova, N.S. & Novikov, V.S. (1985). Sosudistye rasteniia sovetskogo Dal’nego Vostoka 1: 1-383. Izd-vo "Nauka," Leningradskoe otd-nie, Leningrad.
    • Meikle, R.D. (1985). Flora of Cyprus 2: 833-1970. The Bentham-Moxon Trust Royal Botanic Gardens, Kew.
    • Brown, L.C. (1982). The Flora and Fauna of St Helena: 1-88. Land Resources Development Centre, Surbiton, England.
    • Tutin, T.G. & al. (eds.) (1980). Flora Europaea 5: 1-452. Cambridge University Press.
    • Bor, N.L. (1968). Flora of Iraq 9: 1-588. Ministry of Agriculture & Agrarian Reform, Baghdad.
    • Hultén, E.O.G. (1960). Flora of the Aleutian Islands and westernmost Alaska Peninsula: with notes on the flora of Commander Islands, ed. 2: 1-376. Weinheim : J. Cramer ; New York : Hafner Pub. Co.
    • Ovczinnikov, P.N. (ed.) (1957). Flora Tadzhikskoi SSR 1: 1-547. Izd-vo Akademii nauk SSSR, Moskva.
    • Roshevitz, R.J. & al. (eds.) (1950). Flora Kirgizskoi SSR 2: 1-315. Frunze : Izd-vo KirgizFAN SSSR.
    • Merkodovich, N.A. (ed.) (1941). Flora Uzbekistana 1: 1-566. Izd-va Akademii nauk Uzbekskoi SSR, Tashkent.
    • Fedtschenko, B.A. & al. (1932). Flora Turkmenii 1: 1-340. Turkmenskoe gosudarstvennoe izd., Ashkhabad.

    Sources

    GrassBase - The Online World Grass Flora
    http://creativecommons.org/licenses/by-nc-sa/3.0

    Herbarium Catalogue Specimens
    'The Herbarium Catalogue, Royal Botanic Gardens, Kew. Published on the Internet http://www.kew.org/herbcat [accessed on Day Month Year]'. Please enter the date on which you consulted the system.
    Digital Image © Board of Trustees, RBG Kew http://creativecommons.org/licenses/by/3.0/

    Kew Backbone Distributions
    The International Plant Names Index and World Checklist of Selected Plant Families 2019. Published on the Internet at http://www.ipni.org and http://apps.kew.org/wcsp/
    © Copyright 2017 World Checklist of Selected Plant Families. http://creativecommons.org/licenses/by/3.0

    Kew Names and Taxonomic Backbone
    The International Plant Names Index and World Checklist of Selected Plant Families 2019. Published on the Internet at http://www.ipni.org and http://apps.kew.org/wcsp/
    © Copyright 2017 International Plant Names Index and World Checklist of Selected Plant Families. http://creativecommons.org/licenses/by/3.0