Argemone ochroleuca Sweet, Papaveraceae

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Present on Pacific Islands?  no

Primarily a threat at high elevations?  no

Common name(s): [more details]

English: Mexican poppy, pale Mexican poppy, prickly poppy, white thistle, white-flower Mexican-poppy, yellow poppy

Spanish: chicalote

Habit:  herb

Description:  "Annual herb to 1 m tall; sap yellow.  Stems erect, pithy, covered with stiff yellow prickles.  Leaves in a basal rosette when young; stem leaves alternate, light green to blue-green mottled with white, irregularly toothed or lobed with prickles at the tips, margins wavy.  Flowers solitary at the end of the branchlets, pale yellow, 3-7 cm diameter.  Fruit a prickly capsule, 2-5 cm long, opening at the top.  Seeds brown or black, globular, 1.5 mm diameter" (Smith, 2002; p. 58).

Habitat/ecology:  In Australia, "found in seasonal creeks, stream beds, drainage lines and disturbed areas. Competes with native species especially in seasonal creeks and riverbeds. It can restrict movement of animals and cause injury due to its spiny nature." (Smith, 2002; p. 58).  "Grassland, stream beds and alluvial flats of ephemeral streams, disturbed places.  Where invasive, it forms large and dense populations that affect wildlife movement and crowd out native vegetation"  (Weber, 2003; p. 55).

Propagation:  "Seeds produced in large numbers tend to fall near the parent plant producing dense stands. Seeds float and can be moved by water flow. The seed is also dispersed in mud adhering to vehicles, machinery and stock. The plant is known to break off at the base and be blown long distances helping to spread the seed. Seed has also been dispersed as a contaminant in hay and pasture seed." (Smith, 2002; p. 58).

Native range:  Central America, now widespread in warm areas of the world (Smith, 2002; p. 58). Mexico (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)	Northern Territory	introduced invasive	Smith, Nicholas M. (2002) (p. 58)
Australia Australia (continental)	Queensland	introduced invasive	Smith, Nicholas M. (2002) (p. 58)
Mexico Mexico	Mexico (United Mexican States)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
New Zealand New Zealand	New Zealand (country)	introduced invasive	Webb, C. J./Sykes, W. R./Garnock-Jones, P. J. (1988) (p. 927) "Sporadic in waste places, fields, often associated with fowl runs or fowl manure".

Indian Ocean
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Mascarene Islands Mascarene Islands (Mauritius, La Reunion, Rodrigues)	Mascarene Islands	introduced invasive	U.S. Dept. Agr., Agr. Res. Serv. (2013)

Comments:  A declared noxious weed in Western Australia and the Northern Territory (Smith, 2002; p. 58).

Control:  "Control should aim at preventing seed formation.  Plants can be hand pulled, grubbed or cut before fruits ripen.  Seedlings can be sprayed or mowed"

Chemical:  "Effective herbicides are 2,4-D ester, 2,4-D amine, or glyphosate" (Weber, 2003; p. 55).