Pacific Island Ecosystems at Risk (PIER)

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Juncus tenuis
Willd., Juncaceae
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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Common name(s): [more details]

Chinese: jian bei deng xin cao

English: field rush, path rush, slender rush, slender yard rush, soft rush, wiregrass

French: jonc grêle

Habit:  rush

Description:  "Perennial herbs; stems 1-6 dm long, 1-2 mm in diameter, loosely cespitose.  Leaves basal, numerous and crowded, blades variable in length, 7-30 cm long, 1-1.3 mm wide, sheaths loose with wide hyaline margins prolonged into white scarious auricles up to 5 mm long.  Flowers (3-) numerous, borne singly on 1 side of rachis, in relatively compact dichasial cymes 1-7 cm long, forming less than 1/3 of plant, bracts 2-3, foliaceous, usually far exceeding inflorescence, each flower subtended by 2 bracteoles, these hyaline, triangular-ovate; perianth parts greenish, lanceolate, 3-4.5 mm long, apex long-acuminate, outer ones slightly reflexed at apex, inner ones with wide hyaline margins below; stamens 6, 1/2 as long as perianth; anthers shorter than filaments.  Capsules reddish brown, 1-celled, broadly ovoid, thin-walled, slightly beaked, 2/3 to rarely scarcely shorter than perianth.  Seeds pale brown, oblong, 0.3-0.4 mm long, slightly apiculate at both ends"  (Wagner et al., 1999; p. 1454).

Habitat/ecology:  In Hawai‘i, "naturalized in usually wet sites along trails, disturbed places, and pastures, 700-2,000 m"  (Wagner et al., 1999; p. 1454).

Propagation:  Seed

Native range:  North and South America; naturalized elsewhere (GRIN).

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
Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1454)
State of Hawaii
Hawaiian Islands
Kaua‘i Island introduced
invasive
Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1454)
State of Hawaii
Hawaiian Islands
Maui Island introduced
invasive
Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1454)
East Maui
State of Hawaii
Hawaiian Islands
Moloka‘i Island introduced
invasive
Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1454)
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)
New South Wales introduced
invasive
National Herbarium of New South Wales (2013)
Naturalized, scattered, mostly near towns and other areas of human disturbance.
Australia
Australia (continental)
Australia (continental) introduced
invasive
National Herbarium of New South Wales (2013)
Tasmania, Victoria
Naturalised
British Columbia (province of Canada)
Province of British Columbia
Canada (British Columbia) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Central America
Central America (Pacific rim)
Costa Rica (Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Central America
Central America (Pacific rim)
El Salvador (Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Central America
Central America (Pacific rim)
Guatemala (Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Central America
Central America (Pacific rim)
Honduras (Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
China
China
China (People's Republic of) introduced
invasive
Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2013)
Riversides, streamsides, wet grasslands; ca. 400 m. Heilongjiang, Henan, Jiangxi, Shandong, Zhejiang.
Japan
Japan
Japan introduced
invasive
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Naturalized
Japan
Japan
Japan introduced
Mito, Toshikazu/Uesugi, Tetsuro (2004) (p. 191)
var. anthelatus Wiegand and var. nakaii Satake
North Korea
North Korea
North Korea (Democratic People's Republic of)   Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2013)
South Korea
South Korea
South Korea (Republic of)   Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2013)
Mexico
Mexico
Mexico (United Mexican States) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Chiapas, Coahuila, Guerrero, Hidalgo, Mexico, Oaxaca, Veracruz
New Zealand
New Zealand
New Zealand (country) introduced
invasive
Healy, A. J./Edgar, E. (1980) (pp. 92-93)
"Widely occurring, occasional to locally abundant in dry to damp sites, sea-level to over 1000 m".
South America (Pacific rim)
South America (Pacific rim)
Colombia native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
South America (Pacific rim)
South America (Pacific rim)
Ecuador (Republic of) (continental) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
South America (Pacific rim)
South America (Pacific rim)
Perú (Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Taiwan
Taiwan Island
Taiwan Island introduced
invasive
Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2013)
Riversides, streamsides, wet grasslands; ca. 400 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 introduced
invasive
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Naturalized
Also reported from
Country/Terr./St. &
Island group
Location Cited status &
Cited as invasive &
Cited as cultivated &
Cited as aboriginal introduction?
Reference &
Comments
Canada
Canada
Canada 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:  If you know of control methods for Juncus tenuis, please let us know.


Need more info? Have questions? Comments? Information to contribute? Contact PIER! (pier@hear.org)

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This page was created on 11 MAR 2007 and was last updated on 16 MAY 2013.