Sonchus oleraceus L., Asteraceae

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Present on Pacific Islands?  yes

Threat only at high elevations?  no

Other Latin names:  Sonchus asper sensu various authors.

Common name(s): [more details]

Bontoc: gagatang

English: annual milk thistle, annual sow thistle, common sow thistle, hare's-lettuce, milk thistle, sow thistle

Fijian: thandavu

French: laiteron commun, laiteron potager, lastron piquant, polais de lièvre

Hawaiian: pualele

Japanese: nogeshe

Maori (Cook Islands): pū‘ā, pu‘ā, puā

Niuean: puha, pupu lele

Spanish: cerraja, cerrajilla, llisco, morraja, nilhue

Tongan: longolongo‘uha

Habit:  herb

Description:  "An erect, soft, simple or branched, taprooted, annual or sometimes biennial herb; stem smooth, pale bluish green or powdery, sometimes purplish, 30 to 120 cm tall, with milky juice; basal and lower leaves stalked, up to 20 cm long, 3 to 6 cm wide, basal leaves originally rosetted, upper leaves sessile and clasping the stem, the leaves divided into broad toothed and spiny segments with the terminal segments being the largest and triangular, and being green on both sides, sometimes tinged with purple; flowering heads numerous, pale yellow, 2 to 3 cm broad, with smooth involucre; seeds (achene) 2 to 3 mm long, broadest toward the top, tapering to a narrow base, ribbed lengthwise, and transversely wrinkled by the presence of minute warty lumps (tubercles); pappus of numerous silky hairs about 1.5 cm long.  The plant may be distinguished by its toothed leaves, hollow stems, and milky sap.  It has a fibrous taproot" (Holm et al., 1977; p. 436).

"Annual or longer-lived herb, to 50 (-100) cm high, unbranched or with a few branches, glabrous or nearly so, stems often hollow; leaves at base oblong-oblanceolate, pinnately parted, spine-toothed, 15-50 cm long, 5-8 cm wide; middle and upper leaves sessile, basal ones with winged petiole; heads about 2 cm wide; corolla about 1 cm long; achenes slender obovate, about 2.5-3 mm long, transversely scabrously ribbed; pappus about 6-6.5 mm long"  (Stone, 1970; p. 578).

Habitat/ecology:  "The weed is adapted to a number of environments and grows well at low and high elevations in the tropics.  It is usually found in moist conditions in fields, orchards, roadsides, gardens, or waste areas.  It often occur in irrigated lands" (Holm et al., 1977; p. 438).

In Hawai‘i, "naturalized in a variety of disturbed habitats" (Wagner et al., 1999; p. 358).  In Guam, occasional but ephemeral in moist waste ground (Stone, 1970; p. 578).  In Fiji, "naturalized as a weed in clearings and cultivated areas and along forest trails from near sea level to about 900 m"  (Smith, 1991; pp. 265-266).  In Niue, "a common weed in plantations and sometimes in waste places" (Sykes, 1970; p. 68).  "Occasional in disturbed areas" (Whistler, 1988; p. 12). Arid lowlands in the Galápagos Islands; a common weed of disturbed areas such as roadsides and gardens (McMullen, 1999; 197). In New Guinea, "a weed of gardens and field crops; relished by livestock. Sporadic at altitudes from 1000 to 2500 m." (Henty & Pritchard, 1975; p. 79). In New Caledonia, "cité (MacGillivray, 1854) comme mauvaise herbe partout à l'Ile des Pins en 1854. La note de Vieillar & Deplance (1863); "Les néo-calédoniens font un grande usage des feuilles de Sonchus laevis Camer." s'appliquerait probablement à cetter espèce" (MacKee, 1994; p. 38).

Propagation:  "The plant reproduces by seeds that are produced in large quantities and are carried by wind or water" (Holm et al., 1977; p. 436).

Native range:  Europe (Wagner et al., 1999; p. 358). Eurasia and northern Africa (Smith, 1991; pp. 265-266).

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) Lord Howe Island	Lord Howe Island	introduced invasive	Orchard, Anthony E., ed. (1994) (p. 18) "A common weed of disturbed soil". Vouchers cited: P.S. Green 1628 (A, K), J. Pickard 2880 (NSW), J. Pickard 2903 (NSW), J.D. McComish 201 (NSW)
Australia (Pacific offshore islands) Norfolk Islands	Norfolk Island	introduced invasive	Orchard, Anthony E., ed. (1994) (p. 8) "A common weed of disturbed soil". Voucher cited: G. Uhe 1131 (K)
Cook Islands Southern Cook Islands	Aitutaki Atoll		McCormack, Gerald (2007)
Cook Islands Southern Cook Islands	‘Atiu Island		McCormack, Gerald (2007)
Cook Islands Southern Cook Islands	Mangaia Island		McCormack, Gerald (2007)
Cook Islands Southern Cook Islands	Ma‘uke Island		McCormack, Gerald (2007)
Cook Islands Southern Cook Islands	Miti‘aro Island		McCormack, Gerald (2007)
Cook Islands Southern Cook Islands	Rarotonga Island		McCormack, Gerald (2007)
Ecuador (Galápagos Islands) Darwin Islands	Darwin Island	introduced invasive	Charles Darwin Research Station (2005)
Ecuador (Galápagos Islands) Fernandina Group	Fernandina Island	introduced invasive	Charles Darwin Research Station (2005)
Ecuador (Galápagos Islands) Floreana Group	Floreana Island	introduced invasive	Charles Darwin Research Station (2005)
Ecuador (Galápagos Islands) Isabela Group	Volcan Alcedo	introduced invasive	Charles Darwin Research Station (2005)
Ecuador (Galápagos Islands) Isabela Group	Volcan Cerro Azul	introduced invasive	Charles Darwin Research Station (2005)
Ecuador (Galápagos Islands) Isabela Group	Volcan Darwin	introduced invasive	Charles Darwin Research Station (2005)
Ecuador (Galápagos Islands) Isabela Group	Volcan Ecuador	introduced invasive	Charles Darwin Research Station (2005)
Ecuador (Galápagos Islands) Isabela Group	Volcan Sierra Negra	introduced invasive	Charles Darwin Research Station (2005)
Ecuador (Galápagos Islands) San Cristóbal Group	San Cristóbal Island	introduced invasive	Charles Darwin Research Station (2005)
Ecuador (Galápagos Islands) Santa Cruz Group	Santa Cruz Island	introduced invasive	Charles Darwin Research Station (2005)
Ecuador (Galápagos Islands) Santiago Group	Santiago Island	introduced invasive	Charles Darwin Research Station (2005)
Ecuador (Galápagos Islands) Wolf Islands	Wolf Island	introduced invasive	Charles Darwin Research Station (2005)
Federated States of Micronesia Pohnpei Islands	Pohnpei Island		Glassman, S. F. (1952) (p. 97) Voucher cited: Glassman 2581 (US)
Fiji Fiji Islands	Kandavu Island	introduced invasive	Smith, Albert C. (1991) (pp. 265-266) Voucher cited: Smith 302
Fiji Fiji Islands	Lakemba Island	introduced invasive	Smith, Albert C. (1991) (pp. 265-266) Voucher cited: Garnock-Jones 902
Fiji Fiji Islands	Matuku Island	introduced invasive	Smith, Albert C. (1991) (pp. 265-266) Voucher cited: Milne 116
Fiji Fiji Islands	Viti Levu Island	introduced invasive	Smith, Albert C. (1991) (pp. 265-266) Vouchers cited: Greenwood 179, Gillespie 4166, DA 9773, DA 11694, Seemann 266, Simmonds s. n.
French Polynesia French Polynesia Islands	French Polynesia Islands		Waterhouse, D. F. (1997) (p. 65)
French Polynesia Society Islands	Bora Bora Island	introduced invasive	Welsh, S. L. (1998) (p. 80) Voucher cited: Grant 4874
French Polynesia Society Islands	Moorea Island		Fosberg, F. R. (1997) (p. 19)
French Polynesia Society Islands	Raiatea (Havai) Island	introduced invasive	Welsh, S. L. (1998) (p. 80) Voucher cited: Moore 379
French Polynesia Society Islands	Tahiti Island	introduced invasive	Welsh, S. L. (1998) (p. 80) Voucher cited: Grant 3569
Guam Guam Island	Guam Island	introduced invasive	Stone, Benjamin C. (1970) (p. 578)
Guam Guam Island	Guam Island	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 290)
State of Hawaii Hawaiian Islands	French Frigate Shoals	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 358)
State of Hawaii Hawaiian Islands	Hawai‘i (Big) Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 358)
State of Hawaii Hawaiian Islands	Kaho‘olawe Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 358)
State of Hawaii Hawaiian Islands	Kaua‘i Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 358)
State of Hawaii Hawaiian Islands	Ka‘ula Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 358)
State of Hawaii Hawaiian Islands	Kure Atoll	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 358)
State of Hawaii Hawaiian Islands	Lāna‘i Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 358)
State of Hawaii Hawaiian Islands	Lehua Island	introduced invasive	Wood, K. R./LeGrande, Maya (2006) (p. 21) Voucher cited: Flynn et al. 4861 (PTBG)
State of Hawaii Hawaiian Islands	Maui Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 358)
State of Hawaii Hawaiian Islands	Moloka‘i Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 358)
State of Hawaii Hawaiian Islands	Nihoa Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 358)
State of Hawaii Hawaiian Islands	Ni‘ihau Island	introduced invasive	Herbarium Pacificum Staff (1996) (p. 3) Vouchers cited: J.F.G. Stokes s.n. (BISH), H. St. John 23581 (BISH)
State of Hawaii Hawaiian Islands	O‘ahu Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 358)
State of Hawaii Hawaiian Islands	Pearl and Hermes Reef	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 358)
Japan (offshore islands) Bonin (Ogasawara) Islands	Bonin (Ogasawara) Islands		Kato, Hidetoshi (2007)
Japan (offshore islands) Marcus Island	Marcus Island (Minami Tori Shima)	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 290)
Kiribati Line Islands	Tabuaeran (Fanning) Atoll	introduced invasive	Wester, Lyndon (1985) (p. 33)
Kiribati Tungaru (Gilbert) Islands	Tarawa Atoll		Swarbrick, John T. (1997) (p. 97) Presence not verified.
Marshall Islands Ralik Chain	Kwajalein (Kuwajleen) Atoll	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 290)
Marshall Islands Ralik Chain	Kwajalein (Kuwajleen) Atoll	introduced invasive	Whistler, W. A./Steele, O. (1999) (p. 37) Voucher cited: Fosberg 31164. Not found in this survey and may no longer be present.
Marshall Islands Ratak Chain	Arno Atoll	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 290)
Marshall Islands Ratak Chain	Majuro (Mãjro) Atoll	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 290)
New Caledonia Îles Bélep (Belep Islands)	Île Art	introduced invasive	MacKee, H. S. (1994) (p. 38) Voucher cited: MacKee 19446
New Caledonia Hunter Island	Île Hunter	introduced invasive	MacKee, H. S. (1994) (p. 38) Voucher cited: Monzier in Veillon 6941
New Caledonia Îles Loyauté (Loyalte Islands)	Îles Loyauté (Loyalty Islands)	introduced invasive	Tassin, Jacques (2005)
New Caledonia Îles Loyauté (Loyalte Islands)	Île Lifou	introduced invasive	MacKee, H. S. (1994) (p. 38) Voucher cited: MacKee 27278
New Caledonia Îles Loyauté (Loyalte Islands)	Îles Ouvéa (Ouvea Atoll)	introduced invasive	MacKee, H. S. (1994) (p. 38) Voucher cited: MacKee 18905
New Caledonia Îles Loyauté (Loyalte Islands)	Île Tiga	introduced invasive	MacKee, H. S. (1994) (p. 38) Voucher cited: MacKee 45850
New Caledonia Îles Loyauté (Loyalte Islands)	Île Walpole	introduced invasive	MacKee, H. S. (1994) (p. 38) Voucher cited: Cherrier in MacKee 43814
New Caledonia Îles Loyauté (Loyalte Islands)	Île Walpole	introduced	Renevier, Alain/Cherrier, Jean-Francois (1991) (p. 16) Voucher cited: Cherrier in MacKee 44083
New Caledonia Matthew Island	Île Matthew	introduced invasive	MacKee, H. S. (1994) (p. 38) Voucher cited: Veillon 3413 (NOU)
New Caledonia New Caledonia	New Caledonia Islands	introduced invasive	Gargominy, Oliver/Bouchet, Philipe/Pascal, Michel/Jaffre, Tanguy/Tourneu, Jean-Christophe (1996) (p. 379) Rudérale, nombreuses localités
New Caledonia New Caledonia Archipelago	Île Grande Terre	introduced invasive	Tassin, Jacques (2005)
New Caledonia New Caledonia Archipelago	Île Grande Terre	introduced invasive	MacKee, H. S. (1994) (p. 38) Vouchers cited: Balansa 19, Hoff 971 (NOU)
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 invasive	MacKee, H. S. (1994) (p. 38) Voucher cited: Germain s.n.
New Zealand (offshore islands) Kermadec Islands	Kermadec Islands	introduced invasive	Webb, C. J./Sykes, W. R./Garnock-Jones, P. J. (1988) (p. 344) "Waste land, grassland, coastal rocks, dunes and beaches, forest margins, crevices in walls and footpaths, gardens, pasture, roadsides, railway land&
New Zealand (offshore islands) Kermadec Islands	Raoul Island	introduced invasive	Sykes, W. R. (1977) (p. 96) "Waste land, grassland, coastal rocks, dunes and beaches, forest margins, crevices in walls and footpaths, gardens, pasture, roadsides".
Niue Niue	Niue Island	introduced invasive	Sykes, W. R. (1970) (p. 68) Voucher cited: CHR 170428
Niue Niue	Niue Island	introduced invasive	Whistler, W. A. (1988) (p. 12)
Niue Niue	Niue Island	introduced invasive	Whistler, W. A./Atherton, J. (1997) (p. 26)
Niue Niue	Niue Island	introduced invasive	Yuncker, T. G. (1943) (p. 119) Vouchers cited: Yuncker 9758 (BISH), Yuncker 9909 (BISH), Yuncker 10076 (BISH) "A common weed in waste areas and plantations".
Niue Niue	Niue Island	introduced invasive	Space, James C./Waterhouse, Barbara M./Newfield, Melanie/Bull, Cate (2004) (p. 47)
Papua New Guinea Papua New Guinea (eastern New Guinea Island)	Papua New Guinea (eastern New Guinea Island)	introduced invasive	Henty, E. E./Pritchard, G. H. (1975) (p. 79)
Papua New Guinea Papua New Guinea (eastern New Guinea Island)	Papua New Guinea (eastern New Guinea Island)		Waterhouse, D. F. (1997) (p. 65)
Philippines Philippine Islands	Philippine Islands	introduced invasive	Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (p. 439)
Pitcairn Islands Pitcairn Islands	Pitcairn Island	introduced	St. John, H. (1987) (p. 54) Voucher cited: Fosberg & B. Christian 11212
Pitcairn Islands Pitcairn Islands	Pitcairn Island	introduced	Fosberg, F. R./Paulay, Gustav/Spencer, T./Oliver, Royce (1989) (p. 15) Voucher cited: Paulay, Spencer & Schuster 671 (US)
Samoa Western Samoa Islands	Western Samoa Islands		Waterhouse, D. F. (1997) (p. 65)
Tonga Tonga Islands	Tonga Islands		Whistler, W. A. (1988) (p. 12)
Tonga Tonga Islands	Tonga Islands	introduced invasive	Yuncker, T. G. (1959) (p. 270) "Probably grows throughout Tonga".
Tonga Tongatapu Group	Tongatapu Island	introduced invasive	Yuncker, T. G. (1959) (p. 270) Voucher cited: Yuncker 16239
Tonga Vava‘u Group	Late Island	introduced	Sykes, W. R. (1981) (p. 349)
United States (other Pacific offshore islands) Johnston Atoll	Johnston Island	introduced invasive	Amerson, A. Binion, Jr./Shelton, Philip C. (1976) (p. 60) Identification uncertain. May be Sonchus asper.
United States (other Pacific offshore islands) Midway Atoll	Midway Atoll	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 358)
United States (other Pacific offshore islands) Wake Islands	Wake Island	introduced invasive	Fosberg, F. R. (1959) (p. 19) Voucher cited: Fosberg 34464, Fosberg 34483 Rare weed.
United States (other Pacific offshore islands) Wake Islands	Wake Island	introduced	Fosberg, F. R./Sachet, M.-H. (1969) (p. 15) Not seen in 1961 or 1963.
United States (other Pacific offshore islands) Wake Islands	Wake Island	introduced invasive	Fosberg, F. R. (1955) (p. 22) Vouchers cited: Fosberg 34464 (US), Fosberg 34483 (US)
Vanuatu New Hebrides Islands	Vanuatu (Republic of)		Swarbrick, John T. (1997) (p. 97)
Wallis and Futuna Wallis and Futuna (Horne) Islands	Wallis and Futuna Islands		Whistler, W. A. (1988) (p. 12)

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)	Australia (continental)	introduced invasive	Weber, Ewald (2003) (p. 413)
Australia Australia (continental)	Queensland	introduced invasive	Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (p. 439)
Cambodia Cambodia	Cambodia (Kingdom of)		Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. (1979) (p. 345)
Chile (continental) Chile	Chile (Republic of)	introduced invasive	Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (p. 439)
China China	China (People's Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2007)
Colombia Colombia	Colombia (Republic of)	introduced invasive	Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (p. 439)
Costa Rica Costa Rica	Costa Rica (Republic of)		Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. (1979) (p. 345)
Indonesia Indonesia	Indonesia (Republic of)	introduced invasive	Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (p. 439)
Japan Japan	Japan (country)	introduced invasive	Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (p. 439)
North Korea North Korea	North Korea (Democratic People's Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2007)
South Korea South Korea	South Korea (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2007)
Mexico Mexico	Mexico (United Mexican States)	introduced invasive	Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (p. 439)
New Zealand New Zealand	New Zealand (country)	introduced invasive	Webb, C. J./Sykes, W. R./Garnock-Jones, P. J. (1988) (p. 344) "Waste land, grassland, coastal rocks, dunes and beaches, forest margins, crevices in walls and footpaths, gardens, pasture, roadsides, railway land".
Perú Perú	Perú (Republic of)	introduced invasive	Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (p. 439)
Taiwan Taiwan	Taiwan Island	introduced invasive	Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (p. 439)
Vietnam Vietnam	Vietnam (Socialist Republic of)	introduced invasive	Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (p. 439)

Indian Ocean
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Australia (Indian Ocean offshore islands) Christmas Island Group	Christmas Island	introduced invasive	Swarbrick, J. T. (1997) (p. 128)
Australia (Indian Ocean offshore islands) Cocos (Keeling) Islands	Cocos (Keeling) Islands	introduced	Williams, D. G. (1994) (p. 22)
Mauritius Mautitius Islands (Mauritius and Rodrigues)	Mauritius Island	introduced invasive	Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (p. 439)

Control: 

Physical:  "Since plants do not regenerate from root fragments, physical control by cutting or mowing may control the plant".

Chemical:  "Effective pre-emergence herbicides are simazine or atrazine.  Seedlings and rosettes are sprayed with MCPA or 2,4-D"  (Weber, 2003; p. 413).

Additional information:  Additional online information about Sonchus oleraceus is available from the Hawaiian Ecosystems at Risk project (HEAR).

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

References:

Amerson, A. Binion, Jr./Shelton, Philip C. 1976. The natural history of Johnston Atoll. Atoll Research Bulletin No. 192. Smithsonian Institution, Washington. 479 pp.

Charles Darwin Research Station. 2005. CDRS Herbarium records.

Fosberg, F. R. 1955. Northern Marshall Islands Expedition, 1951-1952. Land biota: vascular plants. Atoll Research Bulletin No. 39. Pacific Science Board, National Academy of Sciences, Washington. 22 pp.

Fosberg, F. R. 1959. Vegetation and flora of Wake Island. Atoll Research Bulletin 67. Pacific Science Board, National Academy of Sciences, Washington. 20 pp.

Fosberg, F. R. 1997. Preliminary checklist of the flowering plants and ferns of the Society Islands. Ed. by David R. Stoddart. U. Cal. Berkeley.

Fosberg, F. R./Paulay, Gustav/Spencer, T./Oliver, Royce. 1989. New collections and notes on the plants of Henderson, Pitcairn, Oeno, and Ducie Islands. Atoll Research Bulletin No. 329. Smithsonian Institution, Washington. 18 pp.

Fosberg, F. R./Sachet, M.-H. 1969. Wake Island vegetation and flora, 1961-1963. Atoll Research Bulletin No. 123. Smithsonian Institution, Washington. 15 pp.

Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce. 1979. A geographical checklist of the Micronesian dicotyledonae. Micronesica 15:1-295.

Gargominy, Oliver/Bouchet, Philipe/Pascal, Michel/Jaffre, Tanguy/Tourneu, Jean-Christophe. 1996. Conséquences des introductions d'espèces animales et végétales sur la biodiversité en Nouvelle-Calédonie. Rev. Ecol. (Terre Vie) 51:375-401.

Glassman, S. F. 1952. The flora of Ponape. Bishop Mus. Bull. 209: 1-152.

Henty, E. E./Pritchard, G. H. 1975. Weeds of New Guinea and their control. 2nd edition. Department of Forests, Division of Botany, Botany Bull. No. 7. Lae, Papua New Guinea. 180 pp.

Herbarium Pacificum Staff. 1996. New Hawaiian pest plant records for 1995. In: Evenhuis, Neal L. and Miller, Scott, E., eds. Records of the Hawaii Biological Survey for 1995. Part 2: Notes. Bishop Museum Occasional Papers. 46:3-8.

Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. 1977. The world’s worst weeds: distribution and biology. East-West Center/University Press of Hawaii. 609 pp.

Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. 1979. A geographical atlas of world weeds. John Wiley & Sons, New York. 391 pp.

Kato, Hidetoshi. 2007. Herbarium records of Makino Herbarium, Tokyo Metropolitan University. Personal communication.

MacKee, H. S. 1994. Catalogue des plantes introduites et cultivées en Nouvelle-Calédonie. Muséum National d'Histoire Naturelle, Paris, 164 p.

McCormack, Gerald. 2007. Cook Islands biodiversity and natural heritage. On-line database.

McMullen, C. K. 1999. Flowering plants of the Galápagos. Comstock Pub. Assoc., Ithaca, N.Y. 370 p.

Orchard, Anthony E., ed. 1994. Flora of Australia. Vol. 49, Oceanic islands 1. Australian Government Publishing Service, Canberra.

Renevier, Alain/Cherrier, Jean-Francois. 1991. Flore et vegetation de l'Ile de Walpole. Smithsonian Institution, Atoll Research Bulletin No. 352. 21 pp.

Smith, Albert C. 1991. Flora Vitiensis nova: a new flora of Fiji. National Tropical Botanical Garden, Lawai, Kauai, Hawaii. Volume 5. 626 pp.

Space, James C./Waterhouse, Barbara M./Newfield, Melanie/Bull, Cate. 2004. Report to the Government of Niue and the United Nations Development Programme: Invasive plant species on Niue following Cyclone Heta. UNDP NIU/98/G31 - Niue Enabling Activity. 80 pp.

St. John, H. 1987. An account of the flora of Pitcairn Island with new Pandanus species. Honolulu, 65 pp.

Stone, Benjamin C. 1970. The flora of Guam. Micronesica 6:1-659.

Swarbrick, J. T. 1997. Environmental weeds and exotic plants on Christmas Island, Indian Ocean: a report to Parks Australia. 101 pp. plus appendix.

Swarbrick, John T. 1997. Weeds of the Pacific Islands. Technical paper no. 209. South Pacific Commission, Noumea, New Caledonia. 124 pp.

Sykes, W. R. 1970. Contributions to the flora of Niue. New Zealand Department of Scientific and Industrial Research Bulletin 200, Wellington. 321 pp.

Sykes, W. R. 1977. Kermadec Islands flora: an annotated checklist. New Zealand Department of Scientific and Industrial Research Bulletin 219, Wellington. 216 pp.

Sykes, W. R. 1981. The vegetation of Late, Tonga. Allertonia 2(6):323-353.

Tassin, Jacques. 2005. Jacques Tassin (IAC-CIRAD), personal communication.

U.S. Dept. Agr., Agr. Res. Serv. 2007. National Genetic Resources Program. Germplasm Resources Information Network (GRIN). Online searchable database.

Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. 1999. Manual of the flowering plants of Hawaii. Revised edition. Bernice P. Bishop Museum special publication. University of Hawai‘i Press/Bishop Museum Press, Honolulu. 1919 pp. (two volumes).

Waterhouse, D. F. 1997. The major invertebrate pests and weeds of agriculture and plantation forestry in the Southern and Western Pacific. The Australian Centre for International Agricultural Research, Canberra. 93 pp.

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.

Welsh, S. L. 1998. Flora Societensis: A summary revision of the flowering plants of the Society Islands. E.P.S. Inc., Orem, Utah. 420 pp.

Wester, Lyndon. 1985. Checklist of the vascular plants of the northern Line Islands. Smithsonian Institution, Washington. Atoll Reseach Bulletin 287:1-38.

Whistler, W. A. 1988. Checklist of the weed flora of western Polynesia. Technical Paper No. 194, South Pacific Commission, Noumea, New Caledonia. 69 pp.

Whistler, W. A./Atherton, J. 1997. Botanical survey of the Huvalu Forest Conservation Area, Niue. Unpublished technical report. 76 pp.

Whistler, W. A./Steele, O. 1999. Botanical survey of the United States of America Kwajalein Atoll (USAKA) Islands. Prepared for Oak Ridge Institute for Science and Education and the U. S. Army Environmental Center. 111 pp.

Wiggins, I. L./Porter, D. M. 1971. Flora of the Galapágos Islands. Stanford University Press. 998 pp.

Williams, D. G. 1994. Vegetation and flora of the Cocos (Keeling) Islands. Atoll Research Bulletin No. 404. Smithsonian Institution, Washington. 29 pp.

Wood, K. R./LeGrande, Maya. 2006. An annotated checklist and new island records of flowering plants from Lehua Islet, Ni‘ihau, Hawai‘i. In: Evenhuis, Neal L. and Eldredge, Lucias G., eds. Records of the Hawaii Biological Survey for 2004-2005. Part 1: Articles. Bishop Museum Occasional Papers 87:19-29.

Yuncker, T. G. 1943. The flora of Niue Island. Bishop Mus. Bull. 178. Bishop Museum Press, Honolulu. 126 pp.

Yuncker, T. G. 1959. Plants of Tonga. Bishop Museum Bull. 220. Bishop Museum Press, Honolulu. 343 pp.