Cladium (fen-sedge,sawgrass ortwig-sedge) is a genus of largesedges, 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, andflowering stems 1–3 m tall bearing a much-branchedinflorescence. Like many plants found in wet habitats, it has deeply buried rhizomes that can produce tall shoots with dense canopies.[2]
Cladium mariscussubsp. jamaicense, or saw-grass, is common in marshes and savannas throughout the tropicalAmericas. One typical and well-known area of extensive saw-grass growth is theFloridaEverglades;[3] 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 inphosphorus.[4] 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.[5]American alligators also use sawgrass to build nests.[6] Phosphorus fromagricultural runoff favoured densecattail over rich sawgrass habitats, choking off water access for animals and birds. Eighty plant and animal species in the Everglades are threatened or endangered.[7]
Cladium mariscoides, or twig-rush, is also a wetland plant, but is found further north, and in other kinds of wetlands includingfens,[8]wet meadows[9] and pond shores.[10] Owing to such specific habitat requirements, it is quite rare in the northern states such as Minnesota.[11] "Finding a self-sustaining population ofC. mariscoides on a lake shore is indeed a very rare event in Minnesota".[11]
Cladium mariscus is frequently encountered in English fens.[12] Its ability to form dense stands can lead to reduced plant diversity.[13] Hence, it is sometimes mowed to reduce dominance.[14]
Sawgrass may be useful as a source for developingbiofuel (ethanol), possibly replacingcorn as thecellulose (the basis for developing ethanol) source of choice.[15] On Gotland, a limestone island in the Baltic sea, Cladium mariscus is used for thatching.
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.[1]
Cladium mariscus subsp.jamaicense (Crantz) Kük. – Latin America from Mexico to Argentina; West Indies; southeastern United States from Texas to Delaware; 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
^Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. p. 89
^Loveless, C. M. 1959. "A study of the vegetation in the Florida Everglades".Ecology 40: 1–9.
^Davis, S. M. and Ogden, J. C. (eds.) 1994.Everglades: The Ecosystem and its Restoration. Delray Beach, FL: St. Lucie Press.
^White, P. S. (1994). "Synthesis: vegetation pattern and process in the Everglades ecosystem". InEverglades: The Ecosystem and Its Restoration, eds. S. Davis and J. Ogden, pp. 445–60. DelRay Beach, FL: St. Lucie Press.
^Lodge, Thomas E. (1994).The Everglades Handbook: Understanding the Ecosystem. St. Lucie Press, DelRay Beach, Fl.
^Richard Blaustein: "Climate change prompts a rethink of Everglades management".Science News, October 18, 2018.doi:10.1126/science.aav7879.
^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.
^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.
^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.
^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.
^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.
^Angiosperm Fruits and Seeds from the Middle Miocene of Jutland (Denmark) byElse Marie Friis, The Royal Danish Academy of Sciences and Letters 24:3, 1985
