Amaranthus hybridus L., Amaranthaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Other Latin names:  Amaranthus incurvatus Timeroy ex Gren. & Godr.; Amaranthus patulus Bertol.

Common name(s): [more details]

Chinese: lü sui xian

English: green amaranth, green pigweed, hybrid amaranth, prince's feather, red root, slim amaranth, smooth amaranth, smooth pigweed, spleen amaranth, wild cabbage

Fijian: ndriti

Japanese: hoso-ao-geito

Spanish: amaranto, bledo, blero, crista de galo, lero, moco de pavo, penacho, quelite, visnaga, yuyo, yuyo hembra

Habit:  herb

Description:  "Monoecious annual herbs 10-20 (-30) dm tall; stems often tinged reddish, erect, occasionally ascending, branched, striate, glabrous to moderately pubescent with multicellular hairs.  Leaves lanceolate to ovate or rhombic, blades 3-19 (-30) cm long, 1.5-8 (-12) cm wide, lower surface glabrous or sparsely pilose along the margins and veins, petioles 0.5-15 cm long.  Flowers yellowish green, reddish, or purple, in axillary and terminal spikes, both sexes mixed throughout the spikes, bracts and bracteoles deltate-ovate, tipped with a long, pale brown to reddish awn; sepals 5, 1.5-3.5 mm long, lanceolate or oblong, apex acute, often awn-tipped, sometimes the apex of pistillate flowers blunt, only the midrib green; stigmas (2) 3.  Fruit subglobose to ovoid, sometimes with a short, inflated or narrow and smooth neck below base of style, 2-3 mm long, dehiscent with a circumscissile lid, the lid smooth.  Seeds black, sometimes shiny, compressed, 0.8-1.3 mm long, faintly reticulate near the margins."  (Wagner et al., 1999; p. 188)

Subsp. hybridus: "The bracteoles of the pistillate flowers are usually 1.5-2 times longer than the sepals and the fruit has a distinct inflated neck" (Wagner et al.,1999; p. 188).

See also A. cruentus.

Habitat/ecology:  In Hawai‘i, "sparingly naturalized at low elevations" (Wagner et al.,1999; p. 188).

Propagation:  "Reproducing from its many seeds, hundreds of which may be produced by each flowering branch, the plant makes rapid early growth, competing quickly with crops"  (Holm et al., 1977; p. 114). The seeds are dispersed by birds.

Native range:  "Apparently indigenous to mild, moist regions from eastern North America to northern South America, the species has now acquired a broad distribution as a naturalized weed" (Smith, 1981; pp. 288-289).

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 invasive	Danton, Philippe/Perrier, Christophe/Martinez Reyes, Guido (2006) (p. 551)
Ecuador (Galápagos Islands) Floreana Group	Campéon Islet, Floreana 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 Sierra Negra, Isabela Island	introduced invasive	Charles Darwin Foundation (2008)
Ecuador (Galápagos Islands) Pinta Group	Pinta 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)
Fiji Fiji Islands	Ovalau Island	introduced invasive cultivated	Smith, Albert C. (1981) (pp. 288-289) Voucher cited: Seemann 367 Garden escape.
Fiji Fiji Islands	Viti Levu Island	introduced invasive cultivated	Smith, Albert C. (1981) (pp. 288-289) Voucher cited: DA 12182 Garden escape.
French Polynesia Society Islands	Tahiti Island	introduced cultivated	Florence, J. (2004) (p. 65) subsp. cruentus (L.) A. Thellung var. paniculatus (L.) A. Thellung
French Polynesia Society Islands	Tahiti Island	introduced cultivated	Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2013) Cultivée
French Polynesia Austral (Tubuai) Islands	Tubuai Island	introduced cultivated	Florence, J. (2004) (p. 65) subsp. cruentus (L.) A. Thellung var. paniculatus (L.) A. Thellung
French Polynesia Austral (Tubuai) Islands	Tubuai Island	introduced cultivated	Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2013) Cultivée
State of Hawaii Hawaiian Islands	Maui Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 188) subsp. hybridus Sparingly naturalized.
State of Hawaii Hawaiian Islands	O‘ahu Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 188) subsp. hybridus Sparingly naturalized.
Kiribati Line Islands	Teraina (Washington) Island	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Nauru Nauru Island	Nauru Island		Wagner, W. L./ Herbst, D. R./Weitzman, A./Lorence, D.H. (2013)

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)	Queensland	introduced invasive	Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (pp. 116-118)
Central America Central America (Pacific rim)	Costa Rica (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Central America Central America (Pacific rim)	El Salvador (Republic of)	introduced invasive	Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (pp. 116-118)
Central America Central America (Pacific rim)	Guatemala (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Central America Central America (Pacific rim)	Nicaragua (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Central America Central America (Pacific rim)	Panama (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
China China	China (People's Republic of)	probably introduced invasive	Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2013) "Farms, waste places, hillsides".
Indonesia Indonesia	Indonesia (Republic of)	introduced invasive	Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (pp. 116-118)
Japan Japan	Japan	introduced invasive	Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (pp. 116-118)
Japan Japan	Japan	introduced	Mito, Toshikazu/Uesugi, Tetsuro (2004) (p. 182)
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. 106)
South America (Pacific rim) South America (Pacific rim)	Chile (Republic of)	introduced invasive	Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (pp. 116-118)
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)	Perú (Republic of)	introduced invasive	Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (pp. 116-118)
Thailand Thailand	Thailand (Kingdom of)		Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. (1979) (p. 19)
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)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
United States (continental except west coast) United States (other states)	USA (Florida)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)

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