Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Common name(s): [more details]

English: amaranth

Marquesan: ea ea mata

Habit:  herb

Description:  "Erect or decumbent, from 6 in. to nearly 2 ft. high. Leaves petiolate, ovate or almost rhomboidal, obtuse, 1/2 in to near 2 in. long. Cymes or clusters dense or at length rather loose, the lower ones axillary, the upper ones forming a long loose spike leafy at the base, either simple or rarely with a few short branches. Bracts and bracteoles shorter than the perianth or about as long, scarcely pointed. Segments of the fruiting perianth 5, narrow, erect, slightly spathulate, shortly but finely pointed, about 3/4 line long, white and scarious on the margins, dark in the centre, those of the male flowers usually 3 only and not dilated upwards. Pericarp membranous, rugose, not ribbed, indehiscent or bursting irregularly, loose over the seed with a short thick summit about as long as the perianth. Styles 2 or rarely 3" (Bentham, 1866; p. 215).

Habitat/ecology:  (no habitat/ecology info known by PIER)

Propagation:  Seed

Native range:  Australia

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
French Polynesia Marquesas Islands	Hiva Oa Island	introduced invasive	Florence, J. (2004) (pp. 60-61)
French Polynesia Marquesas Islands	Hiva Oa Island	introduced invasive	Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2011) Adventice
French Polynesia Society Islands	Tahiti Island	introduced invasive	Florence, J. (2004) (pp. 60-61)
French Polynesia Society Islands	Tahiti Island	introduced invasive	Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2011) Adventice
New Caledonia Récifs D'Entrecasteaux (D'Entrecasteaux Reefs)	Île Surprise	introduced	MacKee, H. S. (1994) (p. 11) Voucher cited: Blanchon 435 (NOU)
New Caledonia Îles Loyauté (Loyalte Islands)	Îles Loyauté (Loyalty Islands)	introduced invasive	Tassin, Jacques (2005)
New Caledonia Îles Loyauté (Loyalte Islands)	Île Lifou	introduced	MacKee, H. S. (1994) (p. 11) Voucher cited: Hoff 1419 (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	MacKee, H. S. (1994) (p. 11) Vouchers cited: Vieillard 1063 s.loc., Pancher, s.n., Balansa 1028, MacDaniels 2049, MacKee 18131, MacKee 26372
Papua New Guinea Papua New Guinea (eastern New Guinea Island)	Papua New Guinea (eastern New Guinea Island)	introduced invasive	Womersley, John S., ed. (1978) (pp. 24-25)
Samoa Western Samoa Islands	Western Samoa Islands		Swarbrick, John T. (1997) (p. 88)
Solomon Islands Solomon Islands	Solomon Islands		Swarbrick, John T. (1997) (p. 88)
Solomon Islands Solomon Islands	Solomon Islands	native	Hancock, I. R./Henderson, C. P. (1988) (p. 46)

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)	native	Bentham, G./Mueller, F. (1864) (p. 214)
Indonesia Indonesia	Indonesia (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011) Lesser Sunda Islands

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

Information about Amaranthus interruptus as a weed (worldwide references) may be available from the Global Compendium of Weeds (GCW).

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

References:

Bentham, G./Mueller, F. 1864. (1967 reprint). Flora Australiensis: A description of the plants of the Australian Territory. Reeve & Co.

Florence, J. 2004. Flore de la Polynésie française, Vol. 2. Paris. IRE Editions, Publications Scientifiques, Collection Faune et Flore Tropicales 41. 503 pp.

Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. 2011. Base de données botaniques Nadeaud de l'Herbier de la Polynésie Française (PAP). (online resource).

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.

Hancock, I. R./Henderson, C. P. 1988. Flora of the Solomon Islands. Research Bulletin No. 7. Ministry of Agriculture and Lands, Honiara. 203 pp.

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

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

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

U.S. Dept. Agr., Agr. Res. Serv. 2011. National Genetic Resources Program. Germplasm Resources Information Network (GRIN). Online searchable database.

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.

Womersley, John S., ed. 1978. Handbooks of the flora of Papua New Guinea, vol. 1. Melbourne University Press, Melbourne. 278 pp.