Pacific Island Ecosystems at Risk (PIER)

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Juncus acutus
L., Juncaceae
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Present on Pacific Islands?  no

Primarily a threat at high elevations?  no

Risk assessment results:  Reject, score: 15 (Go to the risk assessment)

Common name(s): [more details]

English: sharp rush, spiny rush

Habit:  rush

Description:  "Very stout, forming dense prickly tufts; rhizomes stout, woody. Stems (40) -60-100cm x 1.5-5 mm, very stiff and erect, smooth, light green. Basal sheaths shining dark red-brown. Leaves 1-2, basal, terete, similar to stem, with very pungent tip. Inflorescence large, compact 5-15 cm long. Flowers crowded. Tepals c. 3 mm long, ± equal, very hard, outer mucronate, inner truncate to emarginate with wide membranous margin at tip. Stamens 6. Capsule 4.5-5 mm long, much > tepals, ovoid, abruptly tapered, acute, reddish-brown to brownish-orange. Seeds with distinct tails.  Recognised by the dense, robust, stiff, prickly clumps, large congested heads, large reddish-brown to brownish-orange capsules much > tepals, and long-tailed seeds"  (Healy & Edgar, 1980; p. 99).

Habitat/ecology:  "Coastal flats and saline areas, grassland, riparian habitats, disturbed sites.  Native habitats of this plant include sandy seashores, drier parts of salt marshes, and other sandy places.  It is a highly variable species with numerous varieties.  The large and dense tussocks lead to dense patches that support little native vegetation.  In infested watercourses, the plant restricts water flow"  (Weber, 2003; p. 223).

In the United States, "moist saline habitats and alkaline seeps; below 300 m"  (Flora of North America online).  Coastal saline flats where naturalized in New Zealand  (Healy & Edgar, 1980; p. 99).

Propagation:  "Seeds are dispersed mainly by water"  (Weber, 2003; p. 223).

Native range:  Northern Africa, Europe, western Asia, southwestern USA, northern Mexico, Bermuda, southern South America; naturalized in Australia and New Zealand (GRIN).

Presence:

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
National Herbarium of New South Wales (2013)
South Australia, Tasmania, Victoria, Western Australia
Naturalised
Australia
Australia (continental)
New South Wales introduced
invasive
National Herbarium of New South Wales (2013)
A weed of damp areas in temperate regions.
Naturalised
Australia
Australia (continental)
Northern Territory introduced
invasive
National Herbarium of New South Wales (2013)
Naturalised
Australia
Australia (continental)
Queensland introduced
invasive
National Herbarium of New South Wales (2013)
Naturalised
Chile (continental)
Chile
Chile (Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Mexico
Mexico
Mexico (United Mexican States) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Baja Norte, Puebla
New Zealand
New Zealand
New Zealand (country) introduced
invasive
Healy, A. J./Edgar, E. (1980) (p. 99)
Coastal saline flats.
United States (west coast)
United States (west coast states)
USA (California) native
U.S. Dept. Agr., Nat. Res. Cons. 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
United States (continental except west coast)
United States (other states)
United States (other states) native
U.S. Dept. Agr., Nat. Res. Cons. Serv. (2013)
Arizona, Nevada

Control: 

Physical:  "Single tussocks may be removed mechanically.  Cutting at ground level is used for larger infestations, and a follow-up programme is necessary to control regrowth and emerging seedlings".

Chemical:  "Effective herbicides are 2,4-D ester or hexazinone"  (Weber, 2003; p. 223).


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

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This page was created on 15 DEC 2008 and was last updated on 15 MAY 2013.