Pacific Island Ecosystems at Risk (PIER)

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Juncus effusus
L., Juncaceae
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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  yes

Common name(s): [more details]

Chinese: deng xin cao

English: common rush, Japanese mat rush, lamp rush, soft rush

French: jonc à lier, jonc diffus, jonc épars

Spanish: junco de esteras, junquera

Habit:  rush

Description:  "Perennial herbs, rhizomes stout, covered with overlapping scales, roots thick; stems crowded along rhizome, reddish brown to purple at base, striate, terete, 4-8 dm long, pith solid.  Leaves basal, scale-like, bladeless, sheaths dark reddish brown to purple at base, paler toward apex.  Flowers numerous in usually contracted or sometimes more open, cymose inflorescences up to 8 cm long, appearing lateral, lowest bract terete, appearing to be a continuation of the stem, bracteoles 3, colorless, ca. 1/4 as long as perianth; perianth parts pale, rigid, narrow, not obscuring the capsule, outer ones ca. 2.5 mm long, inner ones ca. 2 mm long, about as long as capsule, apex long-acuminate; stamens 3; anthers and filaments about equal.  Capsules pale to medium brown, in contrast to the pale perianth, shiny, 3-celled, ovoid, apex truncate.  Seeds pale brown, ca. 0.5 mm long, ca. 3 times longer than wide"  (Wagner et al., 1999; p. 1453).

Habitat/ecology:  "Freshwater wetlands, wet grassland.  Where native, this plant is found in wet ground, cypress swamps, shores of ponds, marshes, bogs, riparian habitats, and damp woods.  It grows mostly on acid soils.  The species is a troublesome weed of pastures and also invades native communities.  The plant forms dense patches that suppress native species by shading them out, and becomes dominant over large areas.  Single tussocks collate into a continuous cover over time"  (Weber, 2003; p. 225).  "Displaces natives in wet forests and bogs"  (Motooka et al., 2003).

 In Hawai‘i, "cultivated and naturalized along margins of ponds and streams, in open boggy sites, and wet areas along trails, 1,000-2000 m"  (Wagner et al., 1999; p. 1453).

Propagation:  Seed

Native range:  "Widely distributed in temperate regions of both hemispheres" (Wagner et al., 1999; p. 1453).

Presence:

Pacific
Country/Terr./St. &
Island group
Location Cited status &
Cited as invasive &
Cited as cultivated &
Cited as aboriginal introduction?
Reference &
Comments
State of Hawaii
Hawaiian Islands
Hawai‘i (Big) Island introduced
invasive
cultivated
Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1453)
State of Hawaii
Hawaiian Islands
Kaua‘i Island introduced
invasive
Frohlich, Danielle/Lau, Alex (2012) (p. 40)
Voucher cited: T. Flynn 7395 (BISH)
State of Hawaii
Hawaiian Islands
Maui Island introduced
invasive
cultivated
Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1453)
State of Hawaii
Hawaiian Islands
Moloka‘i Island introduced
invasive
cultivated
Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1453)
State of Hawaii
Hawaiian Islands
O‘ahu Island introduced
invasive
Imada, Clyde (2007) (p. 37)
Voucher cited: L.M Crago, C. Imada & C. McGuire 2005-238 (BISH)
Philippines
Philippine Islands
Philippine Islands   Merrill, Elmer D. (1925) (p. 201)
In open swampy places, altitude 1,400 to 2,300 m.
Pacific Rim
Country/Terr./St. &
Island group
Location Cited status &
Cited as invasive &
Cited as cultivated &
Cited as aboriginal introduction?
Reference &
Comments
Australia
Australia (continental)
Australia (continental) introduced
invasive
U.S. Dept. Agr., Agr. Res. Serv. (2013)
South Australia, Tasmania, Western Australia
Naturalised
Australia
Australia (continental)
New South Wales introduced
invasive
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Naturalised
Canada (British Colombia)
Province of British Columbia
Canada (British Columbia) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Chile (continental)
Chile
Chile (Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
China
China
China (People's Republic of) native
Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2013)
Forest margins, wet grasslands, pools, morasses, lake margins, river banks, fields, rice fields; 200-3400 m. Anhui, Fujian, Gansu, Guangdong, Guangxi, Guizhou, Hebei, Heilongjiang, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Jilin, Liaoning, Shandong, Sichuan, Xizang, Yunnan, Zhejiang.
China
China
Hong Kong native
Wu, Te-lin (2001) (p. 306)
In wet places.
Costa Rica
Costa Rica
Costa Rica (Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Ecuador (Mainland)
Ecuador
Ecuador (Republic of) (continental) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
El Salvador
El Salvador
El Salvador (Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Guatemala
Guatemala
Guatemala (Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Honduras
Honduras
Honduras (Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Indonesia
Indonesia
Indonesia (Republic of)   Hafliger, E. (1092) (p. 76)
Japan
Japan
Japan (country)   Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. (1979) (p. 200)
South Korea
South Korea
South Korea (Republic of)   Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. (1979) (p. 200)
Mexico
Mexico
Mexico (United Mexican States) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
New Zealand
New Zealand
New Zealand (country) introduced
invasive
Healy, A. J./Edgar, E. (1980) (p. 95)
"In damp pasture and wet places".
Perú
Perú
Perú (Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Taiwan
Taiwan Island
Taiwan Island native
Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2013)
Forest margins, wet grasslands, pools, morasses, lake margins, river banks, fields, rice fields; 200-3400 m.
United States (west coast)
United States (west coast states)
USA (Oregon) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
United States (west coast)
United States (west coast states)
USA (California) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
United States (west coast)
United States (west coast states)
USA (Washington) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Indian Ocean
Country/Terr./St. &
Island group
Location Cited status &
Cited as invasive &
Cited as cultivated &
Cited as aboriginal introduction?
Reference &
Comments
Mauritius
Mautitius Islands (Mauritius and Rodrigues)
Mauritius Island native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Also reported from
Country/Terr./St. &
Island group
Location Cited status &
Cited as invasive &
Cited as cultivated &
Cited as aboriginal introduction?
Reference &
Comments
Canada (except British Colombia)
Canada
Canada (country) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
United States (continental except west coast)
United States (other states)
United States (other states) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
United States (continental except west coast)
United States (other states)
USA (Florida) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)

Control: 

Physical:  "Cutting at ground level reduces the vigour but a follow-up programme is necessary to treat regrowth and seedlings.  Continuous grazing can eliminate the plant from pastures"  (Weber, 2003; p. 225).

Chemical: "Difficult because of thick rhizomes and roots.  Susceptible to glyphosate at 1-1.5% product applied to foliage (Hank Oppenheimer, Maui Pine"  (Motooka et al., 2003).


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This page was created on 11 MAR 2007 and was last updated on 11 JUL 2013.