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''Cladium'' (Fen-sedge, Sawgrass or Twig-sedge) is a genus of large sedges, with a nearly worldwide distribution in tropical and temperate regions. These are plants characterized by long, narrow (grass-like) leaves having sharp, often serrated (sawtooth-like) margins, and flowering stems 1–3 m tall bearing a much-branched inflorescence. Like many plants found in wet habitats, it has deeply buried rhizomes that can produce tall shoots with dense canopies.〔Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. p. 89〕 ''Cladium mariscus ''subsp.'' jamaicense '', or saw-grass, is common in marshes and savannas throughout the tropical Americas. One typical and well-known area of extensive saw-grass growth is the Florida Everglades;〔Loveless, C. M. 1959. A study of the vegetation in the Florida Everglades. Ecology 40: 1–9.〕 sawgrass is the plant referred to by the descriptor, "River of Grass". Like many species of the Everglades, ''C. jamaicense'' grows in extremely infertile conditions, particularly wet sites that are low in phosphorus.〔Davis, S.M. and Ogden, J.C. (eds.) 1994. Everglades: The Ecosystem and its Restoration. Delray Beach, FL: St. Lucie Press.〕 Dense sawgrass beds are intermingled with other vegetation types. Together they produce a rich array of habitats that support the biological diversity of the Everglades.〔White, P. S. (1994). Synthesis: vegetation pattern and process in the Everglades ecosystem. In Everglades: The Ecosystem and its Restoration, eds. S. Davis and J. Ogden, pp. 445–60. DelRay Beach, FL: St. Lucie Press.〕 American Alligators also use sawgrass to build nests.〔Lodge, Thomas E. 1994. The Everglades Handbook. Understanding the Ecosystem. St. Lucie Press, DelRay Beach, Fl.〕 ''Cladium mariscoides'', or twig-rush, is also a wetland plant, but is found further north, and in other kinds of wetlands including fens,〔Godwin, K. S., Shallenberger, J., Leopold, D. J., and Bedford, B. L. (2002). Linking landscape properties to local hydrogeologic gradients and plant species occurrence in New York fens: a hydrogeologic setting (HGS) framework. Wetlands, 22, 722–37. Table 3.〕 wet meadows 〔Wisheu, I. C. and Keddy, P. A. 1989. The conservation and management of a threatened coastal plain plant community in eastern North America (Nova Scotia, Canada). Biological Conservation, 48, 229–38.〕 and pond shores (). Owing to such specific habitat requirements, it is quite rare in the northern states such as. ''Cladium mariscus'' is frequently encountered in English fens.〔Wheeler, B. D. and Proctor, M. C. F. 2000. Ecological gradients, subdivisions and terminology of north-west European mires. Journal of Ecology, 88, 187–203.〕 Its ability to form dense stands can lead to reduced plant diversity.〔Wheeler, B. D. and K. E. Giller. 1982. Species richness of herbaceous fen vegetation in Broadland, Norfolk in relation to the quantity of aboveground plant material. Journal of Ecology 70: 179–200.〕 Hence, it is sometimes mowed to reduce dominance.〔Elveland, J. and Sjoberg, K. 1982. Some Effects of Scything and Other Management Procedures on the Plant and Animal Life of N. Swedish Wetlands Formerly Mown for Hay, Statens naturvardsverket PM 1516. Solna, Sweden: Forskningssekretariatet.〕 Sawgrass may be useful as a source for developing biofuel (ethanol), possibly replacing corn as the cellulose (the basis for developing ethanol) source of choice.〔(Biofuels on a Big Scale ) from ''ScienceNOW''〕 ==Species== The number of species contained in the genus is disputed, with different authors accepting between two and 60 species as distinct. At present, three species are accepted by Kew Royal Botanic Gardens, one having four subspecies.〔(Kew World Checklist of Selected Plant Families )〕 *''Cladium costatum'' Steyerm. - known only from Venezuela and Guyana *''Cladium mariscoides'' (Muhl.) Torr. – Smooth Sawgrass (eastern North America from Labrador to Manitoba, south to Florida and Texas) *''Cladium mariscus'' (L.) Pohl – Great Fen-sedge, Saw-sedge * *''Cladium mariscus'' subsp. ''californicum'' (S.Watson) Govaerts - California, Arizona, New Mexico, Nevada, Utah, Texas, Sonora, Coahuila * *''Cladium mariscus'' subsp. ''intermedium'' Kük. - Australia, New Caledonia * *''Cladium mariscus'' subsp. ''jamaicense'' (Crantz) Kük. - Latin America from Mexico to Argentina; West Indies; southeastern United States from Texas to Virginia; naturalized in tropical Africa and on many oceanic islands including Canary Islands, Madagascar, New Guinea, Hawaii * *''Cladium mariscus'' subsp. ''mariscus'' - Europe, northern Asia and North Africa from Ireland and Morocco to Japan, including Germany, Italy, France, Scandinavia, Poland, Balkans, Ukraine, Russia, Siberia, Saudi Arabia, Iran, Himalayas, Kazakhstan, China, Korea 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「Cladium」の詳細全文を読む スポンサード リンク
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