Arctotheca calendula (L.) Levyns, Asteraceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Risk assessment results: 

Fertile:  high risk, score: 24 (Go to the risk assessment (Pacific)).
Sterile:  high risk, score: 8 (Go to the risk assessment (Pacific)).
High risk (Go to the risk assessment (United States)) (PDF format).

Other Latin names:  Arctotis calendula L.; Cryptostemma calendula (L.) Druce; Cryptostemma calendulacea R. Br.; Venidium decurrens hort.

Common name(s): [more details]

English: African marigold, Cape dandelion, Capeweed, plain treasure-flower

Habit:  herb

Description:  "Annual rosette herb. Stems sprawling, ascending, up to 30 cm long, rarely 0, with subappressed felty or woolly tomentum and sparse coarse dark multicellular hairs above. Leaves lyrate-pinnatifid to 2-pinnatisect, petiolate, (3)-5-30 x 1-5-(10) cm, with broadly ovate to deltoid terminal lobe and 3-5 pairs of lanceolate, oblong, or oblanceolate lateral lobes, green with scattered short hairs above, silvery with appressed felted tomentum beneath; margins toothed; stem leaves amplexicaul. Capitula solitary on erect scapes. Involucre 1-1.5 cm in diameter. Involucral bracts in 4-5 series, glabrous or sparsely tomentose, greenish; outermost bracts narrowed into a linear terminal appendage; inner bracts oblong, obtuse, usually scarious or dark on margins. Ligules 1.5-2.5 cm long, pale yellow, tinged greenish or purplish beneath. Disc florets dark. Achenes obovoid, weakly flattened with narrow lateral ridges and a weak dorsal ridge, finely wrinkled, dark brown, 2-2.5 mm long, densely covered with long, buff to mauve woolly hairs. Pappus scales brown or purple, scarious, c. 1 mm long"  (Webb et al., 1988; p. 292).

Habitat/ecology:  In New Zealand, "roadsides, coastal sand, pasture, lawns, waste land"  (Webb et al., 1988; p. 292).  In Australia, "Widespread weed of cultivation and pastures"  (New South Wales Flora Online).

Propagation:  Most populations are sterile but spread aggressively by stolons; at least three populations in the flora are fertile and highly invasive (Flora of North America online).

Native range:  Lesotho and South Africa; cultivated and 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
Australia (Pacific offshore islands) Norfolk Islands	Norfolk Island	introduced invasive cultivated	Australian Biological Resources Study (2013) Vouchers cited: G. Uhe 1124 (K), P.S. Green 1877 (K).
State of Hawaii Hawaiian Islands	Maui Island	introduced invasive cultivated	Starr, Forest/Starr, Kim (2011) (pp. 23-24) East Maui. Voucher cited: Starr & Starr 080219-01 (BISH) Sparingly naturalized in lawns and yards.
New Zealand (offshore islands) Kermadec Islands	Raoul Island	introduced invasive	Webb, C. J./Sykes, W. R./Garnock-Jones, P. J. (1988) (p. 292)

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)	Australia (continental)	introduced invasive	National Herbarium of New South Wales (2013) Victoria, Tasmania, Western Australia, South Australia
Australia Australia (continental)	Northern Territory	introduced invasive	National Herbarium of New South Wales (2013)
Australia Australia (continental)	Queensland	introduced invasive	National Herbarium of New South Wales (2013)
Japan Japan	Japan	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. 292)
South America (Pacific rim) South America (Pacific rim)	Chile (Republic of)	introduced invasive	U.S. Dept. Agr., Agr. Res. Serv. (2013) Naturalized
United States (west coast) United States (west coast states)	USA (California)	introduced invasive	Flora of North America Editorial Committee, eds. (2013) "The species is listed by the California Exotic Pest Plant Council (CalEPPC) as a weed with the potential to spread explosively (Red Alert, CDFA A)".

Control:  If you know of control methods for Arctotheca calendula, please let us know.