Pacific Island Ecosystems at Risk (PIER)

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Cotula coronopifolia
L., Asteraceae
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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Common name(s): [more details]

English: bachelor's-button, brassbuttons, buttonweed, common brassbuttons, water buttons, water cotula

French: cotule, cotule à feuilles de sénebière

Spanish: botón de oro

Habit:  herb

Description:  "Ascending to erect, fleshy, glabrous annual or short-lived perennial up to 30 cm tall. Stems terete, branched from base and above, up to 25-(40) cm long, rooting freely from lower nodes. Leaves fleshy, alternate, apetiolate, linear, lanceolate or spathulate, entire, with few irregular large lobes, or shallowly 1-(2)-pinnatisect, usually perfoliate, rarely amplexicaul, (10)-15-80 mm long; leaves above becoming shorter, more triangular, less often divided and more often amplexicaul. Involucral bracts in 2-3 rows, 4-6 mm long. Capitula solitary, bright yellow, (6)-8-10-(13) mm in diameter; peduncles scarcely expanded at apex, solid, 2-7 cm long, c. 1 mm diameter; ♀ florets in 1 or < 1 row, pedicellate, with a corolla; ☿ florets numerous, subsessile, with flattened tubular corolla. Achenes all flattened, hairy on inner surface, glabrous on outer. Achenes of ♀ florets 1.5-2 x 1-1.2 mm; lateral angles with thick, corky, entire, marginal wings. Achenes of ☿ florets 1.1-1.2 x 0.5-0.6 mm; lateral angles thinly ribbed"  (Webb et al., 1988; p. 168).

Description from Flora of North America online.

Habitat/ecology:  Saline and freshwater marshes, swamp edges, streambanks.  A pioneeer plant of bare, wet and nutrient-rich soils, growing both in freshwater and brackish water habitats.  The plant is able to build up dense populations that crowd out native vegetation"  (Weber, 2003; p. 125).

In New Zealand, "Coastal sites, especially lagoons and swamps, also inland in wet sites and waste places"  (Webb et al., 1988; p. 168).  In New South Wales, Australia, "grows in damp, often saline disturbed communities; widespread"  (NSW PlantNET).  "In Chile this species grows in the following environmental conditions: Low altitude, interior valleys; coastal mountains, 500-2000 m; coastal areas, 0-500 m. The plant grows in water or it has its roots within a permanent water course. This corresponds to marshes, bogs, water courses, lake and river shores. Humid areas, with almost constant rainfall. Short dry periods are possible (generally not longer than 1 month).  Fully exposed to the sun. Level areas or slopes facing north. Some shadow. Some protection against direct sunlight, some shadow from vegetation, filtering about 20-40% of light"  (Chileflora).

Propagation:  Seed.  "It is a prolific seed producer, and seeds are mainly dispersed by water.  Weeds remain viable for 1-2 years"  (Weber, 2003; p. 125).

Native range:  Namibia, South Africa (Eastern Cape, Gauteng, Northern Cape, Western Cape); 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
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) (pp. 460, 464, 552)
Chile (offshore islands)
Juan Fernández Islands
Isla Santa Clara introduced
invasive
Atkinson, Rachel/Sawyer, John (2011)
Chile (offshore islands)
Juan Fernández Islands
Isla Santa Clara introduced
invasive
Danton, Philippe/Perrier, Christophe/Martinez Reyes, Guido (2006) (pp. 460, 464, 552)
Voucher cited: Danton B(446)403
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)
Australia
Australia (continental)
Queensland introduced
invasive
National Herbarium of New South Wales (2013)
Canada (British Colombia)
Province of British Columbia
Canada (British Columbia) introduced
invasive
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Naturalized
Chile (continental)
Chile
Chile (Republic of) introduced
invasive
Belov, Michail (2013)
Ecuador (Mainland)
Ecuador
Ecuador (Republic of) (continental) introduced
invasive
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Naturalized
Japan
Japan
Japan (country) introduced
Mito, Toshikazu/Uesugi, Tetsuro (2004) (p. 190)
Mexico
Mexico
Mexico (United Mexican States) introduced
Flora of North America Editorial Committee, eds. (2013)
Baja California
New Zealand
New Zealand
New Zealand (country) uncertain if introduced
invasive
Webb, C. J./Sykes, W. R./Garnock-Jones, P. J. (1988) (p. 168)
Perú
Perú
Perú (Republic of) introduced
invasive
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Naturalized
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
United States (west coast)
United States (west coast states)
USA (Washington) 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 (except British Colombia)
Canada
Canada (country) introduced
invasive
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Naturalized
United States (continental except west coast)
United States (other states)
United States (other states) introduced
invasive
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Alaska, Arizona, Maryland, Nevada
Naturalized


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This page was created on 15 DEC 2010 and was last updated on 17 MAR 2013.