Amaranthus dubius Mart. ex Thell., Amaranthaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Risk assessment results:  Reject, score: 14 (Go to the risk assessment)

Common name(s): [more details]

English: spleen amaranth

Fijian: moca, toyala

French: bràde de Malabar, brède malabar

I-Kiribati: te moota, te mota, te uekeueke

Iloko: kauntong

Spanish: bledo, bledos malezas, pira

Habit:  herb

Description:  "Monoecious, erect annual herbs 4-9 (-15) dm tall; stems usually branched, conspicuously striate, pubescent, especially above, the hairs multicellular.  Leaves ovate to rhombic-ovate, blades 1.5-8 (-12) cm long, 0.7-5 (-8) cm wide, lower surface glabrous to sparsely pilose along the veins, petioles 0.6-5 (-8.5) cm long.  Flowers green, in axillary clusters in the lower part of the plant, in unbranched or rarely branched spikes above, the lower clusters of flowers entirely pistillate, staminate flowers only in the upper 1 cm of the spikes, rarely scattered among pistillate ones, bracts and bracteoles deltate-ovate, awn-tipped; sepals (4) 5, those of staminate flowers broadly lanceolate or lanceolate-oblong, apex acuminate, only the midrib green, those of pistillate flowers oblong or spatulate-oblong, apex obtuse or sometimes acute, mucronulate; stigmas 3.  Fruit ovoid, with a short inflated neck below base of style, 1.5-1.8 mm long, dehiscent with a circumscissile lid, the lid rugulose near the line of dehiscence.  Seeds black, shiny, compressed, 1-1.2 mm long, inconspicuously reticulate"  (Wagner et al., 1999; p. 186).

Habitat/ecology:  "A weed of annual crops, plantations, village gardens, secondary vegetation. Cultivated as a green vegetable throughout its range." (Waterhouse & Mitchell, 1998; pp. 19-20).

In Hawai‘i, "naturalized in disturbed sites"  (Wagner et al., 1999; p. 186).  In Fiji, "occurring near sea level as a weed in clearings, gardens, waste places, and along roadsides" (Smith, 1981; p. 288). In Papua New Guinea, "0-1300 m altitude in several unspecified districts" (Waterhouse & Mitchell, 1998; pp. 19-20); "occurring as a weed in plantations, garden areas and secondary vegetation, at 0-1300 m altitude" (Womersley, 1978)..

Propagation:  "Copious quantities of seed produced" (Waterhouse & Mitchell, 1998; pp. 19-20).

Native range:  Paleotropics (Wagner et al., 1999; p. 186). Tropical America; now occasionally found in the Old World tropics as a weed (Smith, 1981; p. 288).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Commonwealth of the Northern Mariana Islands (US) Northern Mariana Islands	Alamagan Island	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 69)
Commonwealth of the Northern Mariana Islands (US) Northern Mariana Islands	Alamagan Island	introduced invasive	Fosberg, F. R./Falanruw, M. V. C./Sachet, M.-H. (1975) (p. 23) Voucher cited: Fosberg 31690 (US)
Ecuador (Galápagos Islands) Española Group	Española Island	introduced invasive	Charles Darwin Foundation (2008)
Ecuador (Galápagos Islands) Floreana Group	Floreana Island	introduced invasive	Charles Darwin Foundation (2008)
Ecuador (Galápagos Islands) Isabela Group	Isabela Island	introduced invasive	Charles Darwin Foundation (2008)
Ecuador (Galápagos Islands) Isabela Group	Volcán Alcedo, Isabela Island	introduced invasive	Charles Darwin Foundation (2008)
Ecuador (Galápagos Islands) Isabela Group	Volcán Darwin, Isabela Island	introduced invasive	Charles Darwin Foundation (2008)
Ecuador (Galápagos Islands) Isabela Group	Volcán Sierra Negra, Isabela Island	introduced invasive	Charles Darwin Foundation (2008)
Ecuador (Galápagos Islands) San Cristóbal Group	San Cristóbal Island	introduced invasive	Charles Darwin Foundation (2008)
Ecuador (Galápagos Islands) Santa Cruz Group	Santa Cruz Island	introduced invasive	Charles Darwin Foundation (2008)
Ecuador (Galápagos Islands) Santiago Group	Santiago Island	introduced invasive	Charles Darwin Foundation (2008)
Federated States of Micronesia Kosrae Island	Kosrae Island	introduced invasive	Whistler, W. A./Steele, O. (1999) (p. 31)
Federated States of Micronesia Yap Islands	Ulithi Atoll	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 69)
Federated States of Micronesia Yap Islands	Yap (Waqab) Island	introduced invasive	Whistler, W. A./Steele, O. (1999) (p. 31)
Fiji Fiji Islands	Kandavu Island	introduced invasive	Smith, Albert C. (1981) (p. 288) Voucher cited: Smith 303
Fiji Fiji Islands	Viti Levu Island	introduced invasive	Smith, Albert C. (1981) (p. 288) Vouchers cited: Greenwood 66A, Greenwood 66
French Polynesia Society Islands	Tahiti Island	introduced invasive	Welsh, S. L. (1998) (pp. 26-27) Voucher cited: BRY 26049
French Polynesia Society Islands	Tahiti Island	introduced invasive	Florence, J. (2004) (pp. 58-60)
French Polynesia Society Islands	Tahiti Island	introduced invasive	Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2013) Amaranthus cf. dubius Thellung. Voucher cited: J. Florence 2814 (PAP) Mauvaise herbe dans l'ombrière du jardin.
French Polynesia Society Islands	Tupai Island	introduced invasive	Florence, J. (2004) (pp. 58-60)
French Polynesia Society Islands	Tupai Island	introduced	Sachet, M.-H. (1983) (p. 16) Voucher cited: Sachet 2002 (US)
French Polynesia Society Islands	Tupai Island	introduced invasive	Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2013) Adventice
French Polynesia Tuamotu Archipelago	Toau (Tovau) Atoll	introduced invasive	Florence, J. (2004) (pp. 58-60)
French Polynesia Tuamotu Archipelago	Toau (Tovau) Atoll	introduced invasive	Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2013) Adventice
State of Hawaii Hawaiian Islands	Hawai‘i (Big) Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (pp. 186, 188)
State of Hawaii Hawaiian Islands	Kaua‘i Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (pp. 186, 188)
State of Hawaii Hawaiian Islands	Lāna‘i Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (pp. 186, 188)
State of Hawaii Hawaiian Islands	Maui Island	introduced invasive	Starr, Forest/Starr, Kim/Loope, Lloyd L. (2006) (p. 32) East Maui. Voucher cited: Starr, Starr, Medeiros & vonAllmen 040527-1 (BISH)
State of Hawaii Hawaiian Islands	O‘ahu Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (pp. 186, 188) Voucher cited: Herat & Wirawan 212 (BISH)
Kiribati Phoenix Islands	Kanton Island	introduced invasive	Fosberg, F. R./Stoddart, D. R. (1994) (p. 8) Not seen after 1951. Voucher cited: Degener & Hatheway 21295
Kiribati Tungaru (Gilbert) Islands	Abemama Atoll	introduced invasive	Space, James C./Imada, Clyde T. (2004) (p. 76) Voucher: Imada 2003-176 (BISH 697787)
Kiribati Tungaru (Gilbert) Islands	Butaritari Atoll	introduced invasive	Space, James C./Imada, Clyde T. (2004) (p. 77) Voucher: Imada 2003-73 (BISH 697688)
Kiribati Tungaru (Gilbert) Islands	Tarawa Atoll	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 69)
Kiribati Tungaru (Gilbert) Islands	Tarawa Atoll	introduced invasive	Space, James C./Imada, Clyde T. (2004) (p. 73) Voucher: Imada 2003-28 (BISH 697643); Imada 2003-182 (BISH 697793)
Marshall Islands Ralik Chain	Bikini (Pikinni) Atoll	introduced invasive	Whistler, W. A./Steele, O. (1999) (p. 31)
Marshall Islands Ralik Chain	Enewetak (Ãnewetak, Eniwetok) Atoll	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 69)
Marshall Islands Ralik Chain	Enewetak (Ãnewetak, Eniwetok) Atoll	introduced invasive	St. John, Harold (1960) (p. 325) Voucher cited: St. John 23702
Marshall Islands Ralik Chain	Enewetak (Ãnewetak, Eniwetok) Atoll	introduced invasive	Fosberg, F. R. (1955) (p. 9) Voucher cited: Fosberg 24390 (US)
Marshall Islands Ralik Chain	Jaluit (Jãlwõj) Atoll	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 69)
Marshall Islands Ralik Chain	Kwajalein (Kuwajleen) Atoll	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 69)
Marshall Islands Ralik Chain	Kwajalein (Kuwajleen) Atoll	introduced invasive	Whistler, W. A./Steele, O. (1999) (p. 31) Vouchers cited: Fosberg 26503, Fosberg 31178, Herbst 8951. Not seen on this survey and may no longer be present.
Marshall Islands Ralik Chain	Kwajalein (Kuwajleen) Atoll	introduced invasive	Fosberg, F. R. (1955) (p. 9) Vouchers cited: Fosberg 31178 (US), Fosberg 31185 (US), Fosberg 26503 (US)
Marshall Islands Ratak Chain	Majuro (Mãjro) Atoll	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 69)
Marshall Islands Ratak Chain	Majuro (Mãjro) Atoll	introduced invasive	Vander Velde, Nancy (2003) (p. 61)
Nauru Nauru Island	Nauru Island	introduced invasive	Thaman, R. R./Fosberg, F. R./Manner, H. I./Hassall, D. C. (1994) (pp. 84-85) Vouchers cited: Thaman & Manner 22309 (SUVA), Thaman & Manner 22312 (SUVA)
New Caledonia New Caledonia	New Caledonia Islands		Swarbrick, John T. (1997) (p. 88)
New Caledonia New Caledonia	New Caledonia Islands	introduced invasive	Tassin, Jacques (2005)
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. 11) Vouchers cited: MacKee 12165, MacKee 33708
Palau Palau (Belau ) (main island group)	Babeldaob Island	introduced invasive	Space, James C./Waterhouse, Barbara/Miles, Joel E./Tiobech, Joseph/Rengulbai, Kashgar (2003) (p. 100)
Palau Palau (Belau ) (main island group)	Koror (Oreor) Island	introduced invasive	Space, James C./Waterhouse, Barbara/Miles, Joel E./Tiobech, Joseph/Rengulbai, Kashgar (2003) (p. 96)
Palau Palau (Belau ) (main island group)	Malakal (Ngemelachel) Island	introduced invasive	Space, James C./Waterhouse, Barbara/Miles, Joel E./Tiobech, Joseph/Rengulbai, Kashgar (2003) (p. 96)
Papua New Guinea Papua New Guinea (eastern New Guinea Island)	Papua New Guinea (eastern New Guinea Island)	introduced invasive	Waterhouse, B. M./Mitchell, A. A. (1998) (pp. 19-20)
Papua New Guinea Papua New Guinea (eastern New Guinea Island)	Papua New Guinea (eastern New Guinea Island)	introduced invasive	Womersley, John S., ed. (1978) (p. 24)
Philippines Philippine Islands	Philippine Islands	introduced invasive	Waterhouse, B. M./Mitchell, A. A. (1998) (pp. 19-20)
United States (other Pacific offshore islands) Johnston Atoll	Johnston Island	introduced invasive	Amerson, A. Binion, Jr./Shelton, Philip C. (1976) (p. 54)
United States (other Pacific offshore islands) Wake Islands	Wake Island	introduced invasive	Fosberg, F. R. (1959) (p. 12) Voucher cited: Fosberg 34938
United States (other Pacific offshore islands) Wake Islands	Wake Island	introduced invasive	Fosberg, F. R./Sachet, M.-H. (1969) (p. 8) Voucher cited: Sachet 887 (US)
United States (other Pacific offshore islands) Wake Islands	Wake Island	introduced invasive	Fosberg, F. R. (1955) (p. 9) Vouchers cited: Fosberg 34452 (US), Fosberg 34938 (US)

Pacific Rim
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Central America Central America (Pacific rim)	Honduras (Republic of)		Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. (1979) (pp. 18-19)
Central America Central America (Pacific rim)	Nicaragua (Republic of)		Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. (1979) (pp. 18-19)
Indonesia Indonesia	Indonesia (Republic of)	introduced cultivated	U.S. Dept. Agr., Agr. Res. Serv. (2013) Lesser Sunda Islands
Indonesia Indonesia	West Papua Province (Indonesia) (western New Guinea Island) (formerly Irian Jaya)	introduced invasive	Waterhouse, B. M./Mitchell, A. A. (1998) (pp. 19-20)
Mexico Mexico	Mexico (United Mexican States)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
South America (Pacific rim) South America (Pacific rim)	Colombia	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
South America (Pacific rim) South America (Pacific rim)	Ecuador (Republic of) (continental)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
South America (Pacific rim) South America (Pacific rim)	Perú (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Taiwan Taiwan Island	Taiwan Island	introduced invasive	Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2013)

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. 103)
Mauritius Mautitius Islands (Mauritius and Rodrigues)	Mauritius Island		McIntyre, Guy (1991) (p. 11)
Seychelles Seychelles Islands	Coetivy Island		Robertson, S. A./Fosberg, F. R. (1983) (p. 146) Voucher cited: Robertson 1096 (K)
Seychelles Seychelles Islands	Cousin Island	introduced invasive	Fosberg, F. R. (1983) (p. 24) Voucher cited: Fosberg 52034 (US)
Seychelles Seychelles Islands	Desnoeufs Island		Wilson, J. R. (1983) (p. 207)
Seychelles Seychelles Islands	Frégate Island		Robertson, S. A./Todd, D. M. (1983) (p. 44) Voucher cited: Todd 15
Seychelles Seychelles Islands	Marie-Louise Island		Wilson, J. R. (1983) (p. 188)
Seychelles Seychelles Islands	Platte Island		Robertson, S. A./Fosberg, F. R. (1983) (p. 159) Voucher cited: Robertson 3012 (K)
Seychelles Seychelles Islands	Poivre Island		Robertson, S. A./Fosberg, F. R. (1983) (p. 167) Voucher cited: Robertson 2363 (K)
Seychelles Seychelles Islands	Seychelles Islands	introduced	Invasive Species Specialist Group (2017)

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)	USA (Florida)	introduced invasive	U.S. Dept. Agr., Agr. Res. Serv. (2013) Naturalized

Control:  If you know of control methods for Amaranthus dubius, please let us know.