Cotula coronopifolia L., Asteraceae

Click on an image for links to BIGGER PICTURES

Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Common name(s): [more details]

English: brassbuttons, buttonweed, common brassbuttons, water buttons

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 (Cape Province, Transvaal) (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 (2011)
Australia Australia (continental)	Queensland	introduced invasive	National Herbarium of New South Wales (2011)
Canada Province of British Columbia	Canada (British Columbia)	introduced	U.S. Dept. Agr., Nat. Res. Cons. Serv. (2011)
Chile (continental) Chile	Chile (Republic of)	introduced invasive	Belov, Michail (2011)
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. (2011) 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)
United States (west coast) United States (west coast states)	USA (Oregon)	introduced	U.S. Dept. Agr., Nat. Res. Cons. Serv. (2011)
United States (west coast) United States (west coast states)	USA (California)	introduced	U.S. Dept. Agr., Nat. Res. Cons. Serv. (2011)
United States (west coast) United States (west coast states)	USA (Washington)	introduced	U.S. Dept. Agr., Nat. Res. Cons. Serv. (2011)

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	U.S. Dept. Agr., Nat. Res. Cons. Serv. (2011) Alaska, Arizona, Nevada

Additional information:
Photos and other information from Chileflora.
Fact sheet from the Alaska Natural Heritage Program.

Additional online information about Cotula coronopifolia is available from the Hawaiian Ecosystems at Risk project (HEAR).

Information about Cotula coronopifolia as a weed (worldwide references) may be available from the Global Compendium of Weeds (GCW).

Taxonomic information about Cotula coronopifolia may be available from the Germplasm Resources Information Network (GRIN).

References:

Atkinson, Rachel/Sawyer, John. 2011. Naturalized species in the Juan Fernández Archipelago, Chile. Unpublished spreadsheet.

Belov, Michail. 2011. Chileflora (online resource).

Danton, Philippe/Perrier, Christophe/Martinez Reyes, Guido. 2006. Nouveau catalogue de la flore vaculaire de l'archipel Juan Fernández (Chile) [Nuevo catálogo de la flora vacular del Archipélago Juan Fernández (Chile)]. Acta Bot. Gallica 153(4):399-587.

Flora of North America Editorial Committee, eds. 2011. Flora of North America North of Mexico (online edition).

Mito, Toshikazu/Uesugi, Tetsuro. 2004. Invasive alien species in Japan: the status quo and the new regulation for prevention of their adverse effects. Global Environmental Research 8(2)/2004: 171-191.

National Herbarium of New South Wales. 2011. PlantNet: New South Wales Flora online. The Plant Information Network System of the Botanic Gardens Trust Version 2.0. Online resource.

U. S. Government. 2011. Integrated Taxonomic Information System (ITIS) (on-line resource).

U.S. Dept. Agr., Agr. Res. Serv. 2011. National Genetic Resources Program. Germplasm Resources Information Network (GRIN). Online searchable database.

U.S. Dept. Agr., Nat. Res. Cons. Serv. 2011. The PLANTS Database. National Plant Data Center, Baton Rouge, LA 70874-4490 USA.

Webb, C. J./Sykes, W. R./Garnock-Jones, P. J. 1988. Flora of New Zealand, Volume IV: Naturalised pteridophytes, gymnosperms, dicotyledons. Botany Division, DSIR, Christchurch. 1365 pp.

Weber, Ewald. 2003. Invasive plants of the World. CABI Publishing, CAB International, Wallingford, UK. 548 pp.