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Cotton is a soft, fluffy staple fiber that grows in a boll, or protective case, around the seeds of cotton plants of the genus ''Gossypium'' in the family of ''Malvaceae''. The fiber is almost pure cellulose. Under natural conditions, the cotton bolls will tend to increase the dispersal of the seeds. The plant is a shrub native to tropical and subtropical regions around the world, including the Americas, Africa, and India. The greatest diversity of wild cotton species is found in Mexico, followed by Australia and Africa.〔(The Biology of ''Gossypium hirsutum'' L. and ''Gossypium barbadense'' L. (cotton) ). ogtr.gov.au〕 Cotton was independently domesticated in the Old and New Worlds. The fiber is most often spun into yarn or thread and used to make a soft, breathable textile. The use of cotton for fabric is known to date to prehistoric times; fragments of cotton fabric dated from 5000 BC have been excavated in Mexico and the Indus Valley Civilization in Ancient India (modern-day Pakistan and some parts of India). Although cultivated since antiquity, it was the invention of the cotton gin that lowered the cost of production that led to its widespread use, and it is the most widely used natural fiber cloth in clothing today. Current estimates for world production are about 25 million tonnes or 110 million bales annually, accounting for 2.5% of the world's arable land. China is the world's largest producer of cotton, but most of this is used domestically. The United States has been the largest exporter for many years.〔("Natural fibres: Cotton" ), International Year of Natural Fibres〕 In the United States, cotton is usually measured in bales, which measure approximately and weigh .〔National Cotton Council of America, "(U.S. Cotton Bale Dimensions )" (accessed 5 October 2013).〕 ==Types== (詳細はGossypium hirsutum'' – upland cotton, native to Central America, Mexico, the Caribbean and southern Florida (90% of world production) *''Gossypium barbadense'' – known as extra-long staple cotton, native to tropical South America (8% of world production) *''Gossypium arboreum'' – tree cotton, native to India and Pakistan (less than 2%) *''Gossypium herbaceum'' – Levant cotton, native to southern Africa and the Arabian Peninsula (less than 2%) The two New World cotton species account for the vast majority of modern cotton production, but the two Old World species were widely used before the 1900s. While cotton fibers occur naturally in colors of white, brown, pink and green, fears of contaminating the genetics of white cotton have led many cotton-growing locations to ban the growing of colored cotton varieties, which remain a specialty product. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「cotton」の詳細全文を読む スポンサード リンク
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