''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

flower A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechanism ...

ing stems 1–3 m tall bearing a much-branched

inflorescence An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed ...

. Like many plants found in wet habitats, it has deeply buried rhizomes that can produce tall shoots with dense canopies. ''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 Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, a ...

Everglades The Everglades is a natural region A natural region (landscape unit) is a basic geographic unit. Usually, it is a region which is distinguished by its common natural features of geography, geology, and climate. From the ecological point o ...

; 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 Phosphorus is a chemical element with the symbol P and atomic number 15. Elemental phosphorus exists in two major forms, white phosphorus and red phosphorus, but because it is highly reactive, phosphorus is never found as a free element on Ea ...

. 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.

American alligator The American alligator (''Alligator mississippiensis''), sometimes referred to colloquially as a gator or common alligator, is a large crocodilian reptile native to the Southeastern United States. It is one of the two extant species in the ...

s also use sawgrass to build nests. Phosphorus from agricultural runoff favoured dense

cattail ''Typha'' is a genus of about 30 species of monocotyledonous flowering plants in the family Typhaceae. These plants have a variety of common names, in British English as bulrush or reedmace, in American English as reed, cattail, or punks, in ...

over rich sawgrass habitats, choking off water access for animals and birds. Eighty plant and animal species in the Everglades are threatened or endangered. ''Cladium mariscoides'', or twig-rush, is also a wetland plant, but is found further north, and in other kinds of wetlands including

fen A fen is a type of peat-accumulating wetland fed by mineral-rich ground or surface water. It is one of the main types of wetlands along with marshes, swamps, and bogs. Bogs and fens, both peat-forming ecosystems, are also known as mires. T ...

wet meadow A wet meadow is a type of wetland with soils that are saturated for part or all of the growing season. Debate exists whether a wet meadow is a type of marsh or a completely separate type of wetland. Wet prairies and wet savannas are hydrologicall ...

s and pond shores. Owing to such specific habitat requirements, it is quite rare in the northern states such as Minnesota. "Finding a self-sustaining population of ''C. mariscoides'' on a lake shore is indeed a very rare event in Minnesota". ''Cladium mariscus'' is frequently encountered in English fens. Its ability to form dense stands can lead to reduced plant diversity. Hence, it is sometimes mowed to reduce dominance. Sawgrass may be useful as a source for developing biofuel (

ethanol Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound. It is an alcohol with the chemical formula . Its formula can be also written as or (an ethyl group linked to a h ...

), possibly replacing

corn Maize ( ; ''Zea mays'' subsp. ''mays'', from es, maíz after tnq, mahiz), also known as corn ( North American and Australian English), is a cereal grain first domesticated by indigenous peoples in southern Mexico about 10,000 years ago. ...

as the

cellulose Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to many thousands of β(1→4) linked D-glucose units. Cellulose is an important structural component of the primary cell wall ...

(the basis for developing ethanol) source of choice. On Gotland, a limestone island in the Baltic sea, Cladium mariscus is used for thatching.

Fossil record

Several

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

endocarp Fruit anatomy is the plant anatomy of the internal structure of fruit. Fruits are the mature ovary or ovaries of one or more flowers. They are found in three main anatomical categories: aggregate fruits, multiple fruits, and simple fruits. A ...

s of †''Cladium bicorne'' and †''Cladium reidiorum'' have been described from middle Miocene

strata In geology and related fields, a stratum ( : strata) is a layer of rock or sediment characterized by certain lithologic properties or attributes that distinguish it from adjacent layers from which it is separated by visible surfaces known as e ...

of the Fasterholt area near

Silkeborg Silkeborg () is a Danish town with a population of 49,747 (1 January 2022).Jutland Jutland ( da, Jylland ; german: Jütland ; ang, Ēota land ), known anciently as the Cimbric or Cimbrian Peninsula ( la, Cimbricus Chersonesus; da, den Kimbriske Halvø, links=no or ; german: Kimbrische Halbinsel, links=no), is a peninsula of ...

Denmark ) , song = ( en, "King Christian stood by the lofty mast") , song_type = National and royal anthem , image_map = EU-Denmark.svg , map_caption = , subdivision_type = Sovereign state , subdivision_name = Kingdom of Denmark , establishe ...

.Angiosperm Fruits and Seeds from the Middle Miocene of Jutland (Denmark) by Else Marie Friis, The Royal Danish Academy of Sciences and Letters 24:3, 1985

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
/ref> *'' 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 ''Cladium mariscus'' is a species of flowering plant in the sedge family The Cyperaceae are a family of graminoid (grass-like), monocotyledonous flowering plants known as sedges. The family is large, with some 5,500 known species described ...

'' (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 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

References

External links

* http://www.dnr.state.mn.us/rsg/profile.html?action=elementDetail&selectedElement=PMCYP04050 * http://www.nhdfl.org/about-forests-and-lands/bureaus/natural-heritage-bureau/photo-index/twig-rush-sandy-turf-pond-shore.aspx {{Taxonbar, from=Q157782 Cyperaceae genera