Pacific Island Ecosystems at Risk (PIER)

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Carduus pycnocephalus
L., Asteraceae
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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  yes

Common name(s): [more details]

English: compact-headed thistle, Italian plumeless thistle, Italian thistle, sheep thistle, shore thistle, slender thistle, slender winged thistle, slender-flower thistle, winged slender thistle, woolly thistle

Habit:  herb

Description:  "Annual herbs 5-10 dm tall; stems arachnoid pubescent, spiny-winged throughout.  Leaves oblanceolate to oblong-lanceolate, upper surface sparsely pubescent, lower surface arachnoid-woolly, 8-25 cm long, 2.5-6 cm wide, pinnatifid, with 2-5 pairs of lobes, margins spiny, the spines up to 12 mm long, base decumbent for entire internode.  Heads 1-3 in clusters; involucre cylindrical, 1.5-2 cm long, 0.7-1.3 cm in diameter, arachnoid pubescent, the outer bracts spine-tipped, the inner ones up to 1.3 times as long as the middle ones, faintly 3-nerved, attenuate; corollas purple, 10-14 mm long; pappus 10-14 mm long.  Achenes 4-5 mm long, compressed, smooth"  (Wagner et al., 1999; p. 284).

Habitat/ecology:  "Grassland, scrub, woodland, disturbed places.  In the native range, this highly variable species grows on stony hillslopes, in coastal scrub and disturbed places.  Once established where introduced, it can become dominant and exclude native species.  In savannas, it can carry grass fires to tree canopies and thus increases fire hazards"  (Weber, 2003; p. 85).

In Hawai‘i, "naturalized in dry sites, 1,340-2,130"  (Wagner et al., 1999; p. 284).

Propagation:  Seed.  Fruit production is prolific and the long-lived seeds may remain viable up to 10 years  (Weber, 2003; p. 85).

Native range:  Europe (Wagner et al., 1999; p. 284).

Presence:

Pacific
Country/Terr./St. &
Island group
Location Cited status &
Cited as invasive &
Cited as cultivated &
Cited as aboriginal introduction?
Reference &
Comments
Chile (offshore islands)
Rapa Nui (Easter) Island
Rapa Nui (Easter) Island (Isla de Pasqua) introduced
cultivated
Meyer, Jean-Yves (2008) (pp. 40, 41)
"Lefeuvre et al., 2005. Nous n’avons pas vues lors de cette" (Meyer, 2008).
Chile (offshore islands)
Juan Fernández Islands
Isla Más a Tierra (Robinson Crusoe Island) introduced
invasive
Cuevas, Jaime G./Marticorena, Alicia/Cavieres, Lohengrin A. (2004) (p. 535)
Voucher cited: JF 63
Chile (offshore islands)
Juan Fernández Islands
Isla Más a Tierra (Robinson Crusoe Island) introduced
invasive
Atkinson, Rachel/Sawyer, John (2011)
Chile (offshore islands)
Juan Fernández Islands
Isla Más a Tierra (Robinson Crusoe Island) introduced
invasive
Danton, Philippe/Perrier, Christophe/Martinez Reyes, Guido (2006) (p. 552)
State of Hawaii
Hawaiian Islands
Maui Island introduced
invasive
Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 284)
Voucher cited: Wagner 5657 (BISH)
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)
Tasmania, Victoria, Western Australia
Naturalised
Australia
Australia (continental)
New South Wales 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) introduced
invasive
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Naturalized
Japan
Japan
Japan (country) introduced
Mito, Toshikazu/Uesugi, Tetsuro (2004) (p. 189)
New Zealand
New Zealand
New Zealand (country) introduced
invasive
Webb, C. J./Sykes, W. R./Garnock-Jones, P. J. (1988) (p. 300)
"Waste land, pasture, riverbeds, roadsides, railway yards, tussock grassland".
United States (west coast)
United States (west coast states)
USA (Oregon) introduced
invasive
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Naturalized
United States (west coast)
United States (west coast states)
USA (California) 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
United States (continental except west coast)
United States (other states)
United States (other states) introduced
invasive
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Naturalized

Control:  Additional control information from the Bugwood Wiki.

Physical:  "Hand pulling is possible, but the root must be cut at least 10 cm below ground level to prevent regrowth.  Mowed plants can regrow fast and still produce seeds.  Grazing by sheep or goats has been proved to be effective".

Chemical:  "Chemical control is done by herbicides containing glyphosate, picloram, or 2,4-D"  (Weber, 2003; p. 85).


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

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This page was created on 19 FEB 2007 and was last updated on 5 NOV 2011.