Juncus dichotomus

Life-forms

Classification System: APG IV

Superregnum: Eukaryota
Regnum: Plantae
Cladus: Angiosperms
Cladus: Monocots
Cladus: Commelinids
Ordo: Poales

Familia: Juncaceae
Genus: Juncus
Species: Juncus dichotomus
Name

Juncus dichotomus Elliott, 1817
Synonyms

Juncus albicans Fernald, Proc. Amer. Acad. 45: 415 (1910)
Juncus cognatus Kunth, Enum. Pl. 3: 349 (1841)
Juncus dichotomus var. platyphyllus Wiegand, Bull. Torr. Bot. Club 30: 448 (1903)
Juncus platyphyllus (Wiegand) Fernald, Rhodora 47: 124 (1945)
Juncus tenuis ssp. dichotomus (Elliott) Verloove & Lambinon, New J. Bot. 1(1): 40 (2011)
Juncus tenuis var. dichotomus (Elliott) Alph.Wood, Class-book Bot.: 726 (1861)
Juncus tenuis var. platyphyllus (Wiegand) Cory, Rhodora 38: 405 (1936)
Juncus tenuis var. unicornis E.Mey., Linnaea 3: 371 (1828)

Distribution
Native distribution areas:

Continental: Northern America
'Regional:USA
USA (Alabama, Arkansas, Colorado, Connecticut, District of Columbia, Delaware, Florida, Georgia, Louisiana, Massachusetts, Maryland, Maine, Michigan, Mississippi, North Carolina, New Hampshire, New Jersey, New Mexico, New York, Ohio, Oklahoma, Pennsylvania, Rhode Island, South Carolina, Tennessee, Texas, Virginia, West Virginia)
'Regional: Mexico
Mexico (Aguascalientes, Chiapas, Chihuahua, Coahuila, Ciudad de Mexico, Durango, Guanajuato, Hidalgo, Jalisco, Mexico State, Michoacan, Oaxaca, Puebla, Queretaro, San Luis Potosi, Sinaloa, Sonora, Tamaulipas, Tlaxcala, Veracruz, Zacatecas)
Continental: Southern America
'Regional: Central America
Guatemala; Honduras; El Salvador; Costa Rica
'Regional: Caribbean
Jamaica; Hispaniola; Puerto Rico
'Regional: Northern South America
Venezuela (Merida); Bolivia (Chuquisaca, Cochabamba, Santa Cruz, Tarija)
'Regional: Brazil
Brazil (Minas Gerais, Paraná, Rio de Janeiro, São Paulo); S-Brazil (Paraná, Rio Grande do Sul, Santa Catarina)
'Regional: Southern South America
Argentina (Buenos Aires, Catamarca, Cordoba, Corrientes, Entre Rios, Jujuy, La Pampa, Neuquen, Salta, Santiago del Estero, Santa Fe, San Luis, Tucuman); Paraguay (Guaira); Uruguay (Florida, Maldonado, Montevideo, Rio Negro, Rocha, San Jose, Soriano, Tacuarembo, Treinta y Tres)
'Regional: Western South America
Chile (Maule, Bio Bio, Araucania)
Introduced into:
^Austria, Belgium, Italy, New South Wales, New Zealand North, New Zealand South

References: Brummitt, R.K. 2001. TDWG – World Geographical Scheme for Recording Plant Distributions, 2nd Edition
References
Primary references

Elliott, S. 1816–1821. A Sketch of the Botany of South-Carolina and Georgia Volume I. 606 pp., 6 pl. Charleston, SC: J.R. Schenck. BHL Reference page. : 1: 406 (1817).

Additional references

Kirschner, J. & al. (2002). Juncaceae Species Plantarum: Flora of the World 6-8: 1-237, 1-336,1-192. Australian Biological Resources Study, Canberra.

Links

Govaerts, R. et al. 2022. Juncus dichotomus in Kew Science Plants of the World online. The Board of Trustees of the Royal Botanic Gardens, Kew. Published online. Accessed: 2022 Mar 05. Reference page.
Hassler, M. 2022. Juncus dichotomus. World Plants: Synonymic Checklists of the Vascular Plants of the World In: Roskovh, Y., Abucay, L., Orrell, T., Nicolson, D., Bailly, N., Kirk, P., Bourgoin, T., DeWalt, R.E., Decock, W., De Wever, A., Nieukerken, E. van, Zarucchi, J. & Penev, L., eds. 2022. Species 2000 & ITIS Catalogue of Life. Published online. Accessed: 2022 Mar 05. Reference page.
Tropicos.org 2022. Juncus dichotomus. Missouri Botanical Garden. Published online. Accessed: 05 Mar 2022.
International Plant Names Index. 2022. Juncus dichotomus. Published online. Accessed: Mar 05 2022.

Vernacular names
English: Forked rush

Juncus dichotomus (common name is forked rush[3]) is a monocot which belongs to the Juncaceae family of rushes. The plant is native in the Americas in temperate zones but has been introduced to other parts of the world. The species is often confused with other Juncus plants due to morphological similarity. Juncus dichotomus often is found in areas which prove to be very moist, and rainfall is a common occurrence. Juncus dichotomus is often most recognizable in the spring and summer months of the year due to its conspicuous flowers and infructescence.

This plant can be difficult to identify due in part to its similar appearance to other Juncus species.[4] Often Juncus dichotomus is overlooked because it is inconspicuous in the field, and some can be difficult to identify and some consider Juncus dichotomus a weed.

Description

Juncus dichotomus is a graminoid, i.e., a grass-like plant.[5] Juncus dichotomus belongs to the monocot group in which it is a member of a Juncaceae family otherwise known as the rushes.[5] While this species of rush is not tall and lacks many distinctive features making it especially hard to identify by non-specialists. In North America July through August is when Juncus dichotomus is most frequently observed. Juncus dichotomus can occur in dry sites but it thrives best in soils that are damp, such as a roadside ditches where runoff is frequent.[4][6]
Habitat and distribution

Juncus dichotomus is native and distributed widely in the Americas in temperate zones but has been reported as introduced in other temperate climate zones. Juncus dichotomus is a more specialized species least temporarily wet habitats: riverbanks, pond margins, depressions in heaths, sometimes also near rice fields.[7] Flowering and fruiting occurs in late spring—summer in ditches, shores, clearings, and other typically open areas, usually in sandy, well-drained (but frequently wet) soil.[8] Juncus dichotomus usually grows in sandy soils.[4] Any habitat that hold sufficient groundwater with stable temperate temperatures, then this location has the capability to hold a population of J. dichotomus.[5][8]
Taxonomy[1][4]

Juncus dichotomus is considered perennial herbs to 10 dm. Rhizomes densely branched to short creeping. Cataphylls 1--3. Leaves basal; auricles 0.2--0.5(--0.6) mm, scarious to leathery; blade nearly terete, channeled or flat, 10–25(--40) cm(0.5--)0.7--1(--1.2) mm, margins entire. Inflorescences terminal, (5--)10–85(--100)-flowered, congested to somewhat loose, (1--)2.5--10–13) cm; primary bract usually exceeding inflorescence. Flowers: bracteoles 2; tepals green, lanceolate, (3--)3.3--4.5(--5.5) mm; outer and inner series nearly equal; stamens 6, filaments 0.6--1.2 mm, anthers 0.4--0.8(--1) mm; style 0.2 mm. Capsules tan to brown, 1-locular to pseudo-3-locular, ellipsoid to widely. Seeds brownish to amber, ellipsoid to lunate, 0.3--0.4 mm, not tailed. 2n = ca. 80.[9]
Uses

The uses for Juncus dichotomus are limited. Since the plant is often found next to or near water sources which may play a role in preventing erosion.
Management

Juncus dichotomus, a native of the Americas, is also now being reported as invasive in Europe.[4] Juncus dichotomous has been confused with Juncus tenuis, a very widespread plant, in Europe which may have contributed to its spread there.[7] Throughout the southeastern United States and some Northeastern parts on the US found there dichotomus is common.[5] Systemic rusts and smuts have a major effect on individual plants and populations as they affect growth and survival and diseased plants may become distorted, stunted and/or elongated although the results are variable.[10] More work on the life history of J. dichotomus is required to better understand how it responds to disease and other abiotic factors.[10] Management of this species as an invasive in Europe is unclear, although water regime is important and may be manipulated to control the plant as well as herbicides
History

It is clear that Juncus dichotomus has increased its range substantially due to human aided dispersal. Although the biogeographic history of J. dichotomus is somewhat unclear due in part to its similarities with other graminoid species.[4]
References

"IPNI Plant Name Query Results". ipni.org.
The Plant List: A Working List of All Plant Species, retrieved 8 December 2016
USDA, NRCS (n.d.). "Juncus dichotomus". The PLANTS Database (plants.usda.gov). Greensboro, North Carolina: National Plant Data Team. Retrieved 8 December 2016.
Verloove, Filip (1 December 2010). "Juncus dichotomus (Juncaceae) in northwestern Italy, a xenophyte new to Europe". Willdenowia. 40 (2): 173–178. doi:10.3372/wi.40.40202. S2CID 85140553.
"Plants Profile for Juncus dichotomus (forked rush)". plants.usda.gov.
Dowhan, Joseph J.; Rozsa, Ron (July 1989). "Flora of Fire Island, Suffolk County, New York". Bulletin of the Torrey Botanical Club. 116 (3): 265. doi:10.2307/2996816. JSTOR 2996816.
Verloove, Filip (1 January 2010). "Invaders in disguise. Conservation risks derived from misidentification of invasive plants". Management of Biological Invasions. 1 (1): 1–5. doi:10.3391/mbi.2010.1.1.02. ISSN 1989-8649.
"SERNEC - Juncus dichotomus". sernecportal.org.
"Taxon Page". www.efloras.org.
Wennström, Anders (1999). "The effect of systemic rusts and smuts on clonal plants in natural systems". Plant Ecology. 141: 93–97. doi:10.1023/A:1009831202875. S2CID 46682944.