''Juncus roemerianus'' is a species of flowering plant in the rush family known by the common names black rush, needlerush, and black needlerush. It is native to North America, where its main distribution lies along the coastline of the southeastern United States, including the

Gulf Coast The Gulf Coast of the United States, also known as the Gulf South or the South Coast, is the coastline along the Southern United States where they meet the Gulf of Mexico. The coastal states that have a shoreline on the Gulf of Mexico are Tex ...

. It occurs from

New Jersey New Jersey is a U.S. state, state located in both the Mid-Atlantic States, Mid-Atlantic and Northeastern United States, Northeastern regions of the United States. Located at the geographic hub of the urban area, heavily urbanized Northeas ...

Texas Texas ( , ; or ) is the most populous U.S. state, state in the South Central United States, South Central region of the United States. It borders Louisiana to the east, Arkansas to the northeast, Oklahoma to the north, New Mexico to the we ...

, with outlying populations in

Connecticut Connecticut ( ) is a U.S. state, state in the New England region of the Northeastern United States. It borders Rhode Island to the east, Massachusetts to the north, New York (state), New York to the west, and Long Island Sound to the south. ...

New York New York most commonly refers to: * New York (state), a state in the northeastern United States * New York City, the most populous city in the United States, located in the state of New York New York may also refer to: Places United Kingdom * ...

Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...

, and certain

Caribbean The Caribbean ( , ; ; ; ) is a region in the middle of the Americas centered around the Caribbean Sea in the Atlantic Ocean, North Atlantic Ocean, mostly overlapping with the West Indies. Bordered by North America to the north, Central America ...

islands.Uchytil, Ronald J. (1992)
''Juncus roemerianus''.
In: Fire Effects Information System, nline U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory. Retrieved 1-2-2012.

Description

This rush is a perennial plant forming tufts of rough, rigid stems and leaves. It is gray-green in color. The plant may appear to be leafless at first glance, but what look like sharp-pointed stems are actually stiff leaves rolled tightly to form pointed cylinders. The true stems are tipped with

inflorescence In botany, an inflorescence is a group or cluster of flowers arranged on a plant's Plant stem, stem that is composed of a main branch or a system of branches. An inflorescence is categorized on the basis of the arrangement of flowers on a mai ...

s.''Juncus roemerianus''.
University of Florida IFAS Center for Aquatic and Invasive Plants. Retrieved 1-2-2012. It grows from a

rhizome In botany and dendrology, a rhizome ( ) is a modified subterranean plant stem that sends out roots and Shoot (botany), shoots from its Node (botany), nodes. Rhizomes are also called creeping rootstalks or just rootstalks. Rhizomes develop from ...

. This plant is variable in appearance. Its size and shape depend on environmental conditions in its

salt marsh A salt marsh, saltmarsh or salting, also known as a coastal salt marsh or a tidal marsh, is a coastal ecosystem in the upper coastal intertidal zone between land and open saltwater or brackish water that is regularly flooded by the tides. I ...

habitat. In areas with low

soil salinity Soil salinity is the salt (chemistry), salt content in the soil; the process of increasing the salt content is known as salinization (also called salination in American and British English spelling differences, American English). Salts occur nat ...

, the plant can exceed two meters in height, whereas in high-salinity areas the rush is dwarfed, sometimes measuring under 30 centimeters (12 in.) tall. Both large and small plants generally occur in one marsh, with the large plants nearest the open water and the small plants occurring on higher ground in the salt flats and other areas of higher salinity. Plants of different sizes differ genetically, as well, with soil salinity being the selective force leading to the genetic variation. The dwarf plants have an

adaptation In biology, adaptation has three related meanings. Firstly, it is the dynamic evolutionary process of natural selection that fits organisms to their environment, enhancing their evolutionary fitness. Secondly, it is a state reached by the p ...

to high soil salinity. Larger plants lack this adaptation, and do not survive when experimentally transplanted to high-salinity environments.Eleuterius, L. N. (1989)
Natural selection and genetic adaptation to hypersalinity in ''Juncus roemerianus'' Scheele.
''Aquatic Botany'' 36(1) 45–53. Retrieved 1-2-2012.

Reproduction

The plant reproduces sexually by seed and vegetatively by sprouting from its spreading rhizome. It expands its dense, sometimes monotypic stands by sending up new stems from the rhizome, and establishes new stands by broadcasting seeds. The species is gynodioecious, with some plants having bisexual flowers and some having only female reproductive parts. The seeds are very viable, germinating readily, but they require light for germination and may fail to sprout if covered in thick mud. Therefore, seedlings are most often seen in open, sandy stretches, and rarely in areas with dense vegetation or thick substrates. The plant grows new shoots and leaves year-round, and does not typically experience seasonal growth spurts. Dead leaves remain on the plant for a long time, leading to an accumulation of plant matter. The species may form much of the physical structure of the marsh.Christian, R. R., et al. (1990)
''Juncus roemerianus'' production and decomposition along gradients of salinity and hydroperiod.
''Marine Ecology Progress Series'' 68 137–45. Retrieved 1-2-2012.

Ecology

This is a common and ecologically important plant in its range, often dominating salt marshes and

estuaries An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environm ...

. In northwestern

Florida Florida ( ; ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders the Gulf of Mexico to the west, Alabama to the northwest, Georgia (U.S. state), Georgia to the north, the Atlantic ...

perhaps 60% of all the salt marshes are covered in this species of rush. This species and smooth cordgrass (''Spartina alterniflora'') are the dominant plants in

Mississippi Mississippi ( ) is a U.S. state, state in the Southeastern United States, Southeastern and Deep South regions of the United States. It borders Tennessee to the north, Alabama to the east, the Gulf of Mexico to the south, Louisiana to the s ...

tidal marshes.Biber, P. and J. D. Caldwell
Regional Native Plant Nursery for Habitat Restoration.
University of Southern Mississippi Gulf Coast Research Laboratory. Retrieved 1-2-2012. These two species are often found together,Woerner, L. S. and C. T. Hackney. (1997)
Distribution of ''Juncus roemerianus'' in North Carolina tidal marshes: The importance of physical and biotic variables.
''Wetlands'' 17(2) 284–91. with ''S. alterniflora'' occupying lower levels of the marsh and ''J. roemerianus'' growing in the mid-level and upper reaches of the marsh.Touchette, B. W., et al. (2009)
Tolerance and avoidance: Two contrasting physiological responses to salt stress in mature marsh halophytes ''Juncus roemerianus'' Scheele and ''Spartina alterniflora'' Loisel
''Journal of Experimental Marine Biology and Ecology'' 380(1-2) 106–12. Retrieved 1-2-2012. In river estuaries it can occur 10 to 15 miles inland. Other plants occurring in the higher-salinity regions of the marsh include saltmeadow cordgrass (''S. patens''), giant cordgrass (''S. cynosuroides''), saltgrass (''Distichlis spicata''), glassworts (''Salicornia'' spp.), Olney threesquare (''Scirpus americanus''), and saltmarsh bulrush (''Scirpus robustus''). In the

brackish marsh Brackish marshes develop from salt marshes where a significant freshwater influx dilutes the seawater to brackish levels of salinity. This commonly happens upstream from salt marshes by estuaries of coastal rivers or near the mouths of coastal riv ...

, plant associates may include sealavender (''Limonium carolinianum'') and common arrowhead (''Sagittaria latifolia''). In the intermediate marsh between the brackish and freshwater marsh levels, other plants include common reed (''Phragmites australis''), sawgrass (''Cladium jamaicense''), softstem bulrush (''Scirpus validus''), and Virginia iris (''Iris virginica''). This rush provides cover for a number of salt marsh animal species. Birds such as the long-billed marsh wren,

clapper rail The clapper rail (''Rallus crepitans'') is a member of the rail family, Rallidae. The taxonomy for this species is confusing and still being determined. It is a large brown rail that is resident in wetlands along the Atlantic coasts of the easte ...

, and seaside sparrow nest in it. Rice rats nest in it and prey on the eggs of the local birds. A number of fungal species grow on this rush, some exclusively. The

ascomycete Ascomycota is a phylum of the kingdom Fungi that, together with the Basidiomycota, forms the subkingdom Dikarya. Its members are commonly known as the sac fungi or ascomycetes. It is the largest phylum of Fungi, with over 64,000 species. The def ...

species '' Aquamarina speciosa'', '' Keissleriella rara'', '' Massarina carolinensis'', and '' Paraphaeosphaeria pilleata'' were described from dead or dying stems of this rush. Also, the fungus '' Juncigena adarca'' ('' Juncigenaceae'', Torpedosporales) was only found on the senescent leaves (decaying leaves) of ''Juncus roemerianus'', on the Atlantic coast (U.S.A.:

North Carolina North Carolina ( ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It is bordered by Virginia to the north, the Atlantic Ocean to the east, South Carolina to the south, Georgia (U.S. stat ...

Potential uses

This plant has shown potential as an agent of

phytoremediation Phytoremediation technologies use living plants to clean up soil, air and water contaminated with hazardous contaminants. It is defined as "the use of green plants and the associated microorganisms, along with proper soil amendments and agronom ...

after

oil spill An oil spill is the release of a liquid petroleum hydrocarbon into the environment, especially the marine ecosystem, due to human activity, and is a form of pollution. The term is usually given to marine oil spills, where oil is released into th ...

s. When it grows in sediments polluted with

diesel fuel Diesel fuel, also called diesel oil, heavy oil (historically) or simply diesel, is any liquid fuel specifically designed for use in a diesel engine, a type of internal combustion engine in which fuel ignition takes place without a spark as a re ...

it reduces the concentration of total petroleum hydrocarbons,

polycyclic aromatic hydrocarbon A Polycyclic aromatic hydrocarbon (PAH) is any member of a class of organic compounds that is composed of multiple fused aromatic rings. Most are produced by the incomplete combustion of organic matter— by engine exhaust fumes, tobacco, incine ...

s, and n-alkanes in the sediments.Lin, Q. and I. A. Mendelssohn. (2009)
Potential of restoration and phytoremediation with ''Juncus roemerianus'' for diesel-contaminated coastal wetlands.
''Ecological Engineering'' 35 85–91. Retrieved 1-2-2012.

Chemistry

Juncusol is a 9,10-dihydrophenathrene derivative found in ''J. roemerianus''.Antimicrobial activity of juncusol, a novel 9-10-dihydrophenanthrene from the marsh plant Juncus roemerianus. Kirit D. Chapatwala, Armando A. de la Cruz and D.Howard Miles, Life Sciences, 9 November 1981, Volume 29, Issue 19, Pages 1997–2001, The structure of juncusol. A novel cytotoxic dihydrophenanthrene from the Estuarine marsh plant Juncus roemerianus. D H Miles, J Bhattacharyya, N V Mody, J L Atwood, S Black and P A Hedin, Journal of the American Chemical Society, February 1977, volume 99, issue 2, pages 618–620,

References

External links

The Nature Conservancy
{{Taxonbar, from=Q6311898 roemerianus Plants described in 1849 Flora of Northern America