Pacific Island Ecosystems at Risk (PIER)

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Sonchus arvensis
(Juss.) Sweet, Asteraceae
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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Common name(s): [more details]

English: corn sow thistle, field milk thistle, field sow thistle, perennial sow thistle

French: laiteron des champs

Japanese: hachijona, taiwan-hachijona

Spanish: cerraja, cerraja arvense, lechuguilla

Habit:  herb

Description: 

Genus: "Annual or perennial erect herbs or subshrubs with hollow stems, milky latex, and alternate, sessile, simple to pinnately divided, often semiamplexicaul and auriculate leaves; flowering heads homogamous, ligulate, large or fairly large, many-flowered, pedunculate, disposed in cymose corymbiform or paniculiform capitulescences, the phyllaries membranous-margined, in several imbricated series, the receptacle naked; flowers ligulate, perfect, the anther bases sagittate, caudate-acuminate, the style branches thin, subobtuse; achenes obovate to narrowly oblong, ribbed, the pappus dimorphic, of fine narrow bristles and downy capillary hairs, weakly coherent at base." (Smith, 1991)

Species:  "Coarse, freely branched herb 0.3-2 m high, perennial, with abundant milky latex...; flowers dull red in center, yellow at margin, the styles yellow" (Smith, 1991; p. 265).

"A deep-rooted perennial with milky sap in all plant parts; roots creamy-white, fleshy, vertical and horizontal, widely spreading, to 6 mm in diameter; often crooked and easily broken, with buds at close intervals; stems erect 0.5 to 1.5 m tall, hollow, smooth on lower part of plant but often glandular-hairy above, often branched above; leaves variable in size and shape; rosette leaves up to 30 cm long, petiolate, cut into backward-curving lobes, terminal lobe tips broadly triangular; stem leaves crowded on lower stem with weak prickles on margins; upper stem leaves sparse alternate, small, divided or almost entire, margins weakly prickled, sessile and clasping the stem; inflorescence composed of flower heads of 2 to 5 cm in diameter; in large open corymbose clusters; flower florets bright yellow, perfect, ligulate; involucre about 1.5 cm long, the bracts linear-lanceolate, obtuse, the outer densely covered with coarse gland-bristles; peduncle glandular pubescent or smooth; fruit a dark brown to reddish-brown achene, 2.5 to 4.5 mm long, narrowly ovate with the base somewhat truncate, the apex with an expanded collar, somewhat flattened with longitudinally 5 prominent ribs on each side, often slightly curved, transversely wrinkled; pappus composed of numerous simple, persistent, white hairs to 1.5 cm long.  This plant can be distinguished from other Sonchus species by its long, creeping thickened roots with many buds; its relatively large inflorescence of yellow, ligulate flowers; the 5-ribbed achenes; and the presence of glandular hairs on the peduncles of most biotypes.  The hollow stem and milky juice in all plant parts separate it from thistles in other genera"  (Holm et al., 1997; p. 789).

Habitat/ecology:  In Fiji, "found as a naturalized weed in open places, along roadsides, and sometimes in openings along streams in dense forest from near sea level to 400 m" (Smith, 1991; p. 265).

Habitat/ecology:  In Fiji, "found as a naturalized weed in open places, along roadsides, and sometimes in openings along streams in dense forest from near sea level to 400 m" (Smith, 1991; p. 265).

Propagation:  Seed

Native range:  Eurasia, now naturalized elsewhere (Smith, 1991; p. 265).

Presence:

Pacific
Country/Terr./St. &
Island group
Location Cited status &
Cited as invasive &
Cited as cultivated &
Cited as aboriginal introduction?
Reference &
Comments
Fiji
Fiji Islands
Viti Levu Island introduced
invasive
Smith, Albert C. (1991) (p. 265)
Vouchers cited: Smith 8684, DA 2534, DA 9379, DA 9647, DA 11109
New Caledonia
Îles Bélep (Belep Islands)
Île Art introduced
MacKee, H. S. (1994) (p. 38)
Voucher cited: MacKee 30545
New Caledonia
Îles Loyauté (Loyalte Islands)
Îles Ouvéa (Ouvea Atoll) introduced
MacKee, H. S. (1994) (p. 38)
Voucher cited: MacKee 18905
New Caledonia
New Caledonia Archipelago
Île Grande Terre introduced
invasive
Tassin, Jacques (2005)
New Caledonia
New Caledonia Archipelago
Île Grande Terre introduced
MacKee, H. S. (1994) (p. 38)
Vouchers cited: MacKee 13473, MacKee 40954, MacKee 45154
New Caledonia
New Caledonia Archipelago
Île des Pins (Isle of Pines) introduced
invasive
Tassin, Jacques (2005)
New Caledonia
New Caledonia Archipelago
Île des Pins (Isle of Pines) introduced
MacKee, H. S. (1994) (p. 38)
Vouchers cited: MacKee 15790, MacKee 33826
Philippines
Philippine Islands
Philippine Islands introduced
invasive
Merrill, Elmer D. (1923) (p. 621)
In waste places, along trails, old gardens, talus slopes, etc., altitude 1,200 to 2,000 m; unquestionably introduced.
Samoa
Western Samoa Islands
Western Samoa Islands   Swarbrick, John T. (1997) (p. 97)
Tonga
Tonga Islands
Tonga Islands   Swarbrick, John T. (1997) (p. 97)
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
Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 787)
Central America
Central America (Pacific rim)
Guatemala (Republic of) introduced
invasive
Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 793)
China
China
China (People's Republic of)   Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. (1979) (p. 344)
China
China
Hong Kong native
Wu, Te-lin (2001) (p. 287)
In wasteland.
Indonesia
Indonesia
Indonesia (Republic of)   Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 787)
Japan
Japan
Japan   Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 787)
Japan
Japan
Japan introduced
Mito, Toshikazu/Uesugi, Tetsuro (2004) (p. 190)
South Korea
South Korea
South Korea (Republic of)   Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 787)
Mexico
Mexico
Mexico (United Mexican States) introduced
invasive
Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 787)
New Zealand
New Zealand
New Zealand (country) introduced
invasive
Webb, C. J./Sykes, W. R./Garnock-Jones, P. J. (1988) (p. 343)
"Roadsides, hedges, swamps, cultivated land".
Taiwan
Taiwan Island
Taiwan Island probably native
Ching-I Peng, ed. (2013)
"Wastelands and river banks, low to mid elevations, common".
Thailand
Thailand
Thailand (Kingdom of)   Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 787)

Control: 

Biological: "The leaf-gall fly (Cystiphora sonchi) of Europe and the former Soviet Union offer hope of supressing S. asper and S. arvensis in Canada. Females lay eggs on the undersides of leaves, forming up to 270 galls/plant and this insect was initially released in Canada in 1981" (Peschken, 1982, cited in Holm et al., 1997; p. 800).


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This page was created on 20 AUG 2002 and was last updated on 22 JAN 2007.