Madia sativa Molina, Asteraceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  yes

Common name(s): [more details]

English: Chile tarweed, Chilean oilplant, Chilean tarweed, coast tarweed, coastal tarweed, madia-oil-plant, pitchweed, tarplant, tarweed

French: madie cultivée, madie olifère

Spanish: madi, madia, madie, melosa

Habit:  herb

Description:  "Plants (0.3-) 35-100 (-240) cm, self-compatible (heads not showy). Stems hirsute and glandular-pubescent, glands yellowish, purple, or black, lateral branches rarely surpassing main stems. Leaf blades broadly lanceolate to linear-oblong or linear, 2-18 cm x 3-18 (-29) mm. Heads in usually crowded, paniculiform, racemiform, or spiciform arrays. Involucres ovoid to urceolate, 6-16 mm. Phyllaries hirsute and glandular-pubescent, glands yellowish, purple, or black, apices erect or ± reflexed, flat. Paleae mostly persistent, connate 1/2+ their lengths. Ray florets (5-) 8-13; corollas greenish yellow or sometimes purplish red abaxially or throughout, laminae 1.5-4 mm. Disc florets 11-14, bisexual, fertile; corollas 2-5 mm, pubescent; anthers ± dark purple. Ray cypselae black or brown, sometimes mottled, dull, compressed, beakless. Disc cypselae similar"  (Flora of North America online).

Habitat/ecology:  In the United States (native), "grasslands, openings in shrublands and woods, disturbed sites, stream banks, roadsides; 0-1000 m"  (Flora of North America online).  In New Zealand, "Waste places, coastal sites, cultivated land and pasture"  (Webb et al., 1988; p. 224).  "In Chile this species grows in the following environmental conditions:   Medium altitude up to the timber line; low altitude, interior valleys; coastal mountains, 500=2000 m; coastal areas, 0-500 m. Humid areas, with almost constant rainfall, hort dry periods are possible (generally not longer than 1 month); somewhat dry areas where the drought may last 3-5 months, precipitations of 400-800 mm. are concentrated in winter; dry, arid areas, with long drought periods of 6-10 months, precipitations of 100-300 mm. are concentrated in winter. 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

Native range:  Canada (British Columbia), United States (Oregon, Washington, California), Argentina, Chile; 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
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	Danton, Philippe/Perrier, Christophe/Martinez Reyes, Guido (2006) (pp. 458, 459, 555) "Planta colectada una sola vez en 1986, 'una sola planta vista en una pradera cerca del mar'. Nunca hemos visto esta especie en terreno. Posiblemente se trata de una adventicia fugaz, pero si tuvo la oportunidad de producir semillas antes de su colecta, podría reaparecer algún dia".de Alfredo d
State of Hawaii Hawaiian Islands	Maui Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 345) var. sativa. Known only from Haleakalā Crater. Voucher cited: Degener 7449 (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)	New South Wales	introduced invasive	National Herbarium of New South Wales (2013)
Australia Australia (continental)	Australia (continental)	introduced invasive	U.S. Dept. Agr., Agr. Res. Serv. (2013) Victoria
British Columbia (province of Canada) Province of British Columbia	Canada (British Columbia)	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. 224)
South America (Pacific rim) South America (Pacific rim)	Chile (Republic of)	native cultivated	U.S. Dept. Agr., Agr. Res. Serv. (2013) Also cultivated.
United States (west coast) United States (west coast states)	USA (Oregon)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
United States (west coast) United States (west coast states)	USA (California)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
United States (west coast) United States (west coast states)	USA (Washington)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)

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) Adventive

Control:  If you know of control methods for Madia sativa, please let us know.