Alternanthera pungens Kunth, Amaranthaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Risk assessment results:  Reject, score: 17 (Go to the risk assessment)

Common name(s): [more details]

English: khaki weed

Spanish: hierba del pollo

Habit:  herb

Description:  "Perennial herbs; stems prostrate, rarely ascending, sometimes rooting at the nodes, 1-5 dm long, pilose, the hairs multicellular.  Leaves ovate to obovate, 0.5-4.5 cm long, 0.3-2 cm wide, glabrous to sparsely appressed pilose, petioles 2-10 mm long.  Flowers in sessile, sparsely pubescent spikes, bract ca. 4 mm long, tipped with a spine 2-3 mm long, bracteoles 3-4 mm long, acute; sepals unequal, the 2 abaxial ones 4-5 mm long, spine-tipped, the spine usually more than 2 mm long, other sepals not spine-tipped; stamens 5, all fertile.  Utricles 1.2-1.5 mm long, enclosed by the sepals"  (Wagner et al., 1999; pp. 183-185).

Habitat/ecology:  "Colonises bare ground and disturbed areas usually forming a dense mat, particularly around houses, lawns, camp sites, stockyards or overgrazed areas. Known to invade native pastures and out-compete more desirable species. Its large taproot makes control difficult." (Smith, 2002; p. 57). In Hawai‘i, "a common weed of beach parks and other low elevation, dry, disturbed areas" (Wagner et al., 1999; pp. 183-185). In New Guinea, "a weed of pastures; suspected of causing deaths of pigs and digestive disturbances and dermatitis of cattle" (Henty & Pritchard, 1975; p. 52).  In Papua New Guinea, "a weed of dry open habitats at 0-750(?) m altitude"  (Womersley, 1978).

Propagation:  "Burrs carrying seeds are spread when attached to clothing, footwear, swags, tyres, machinery and animals. Water will spread the burrs short distances. Some spread has been recorded by the movement of fodder. Populations can expand by roots forming at the nodes and by fragmentation." (Smith, 2002; p. 57).

Native range:  Neotropics, now widely naturalized in many parts of the world (Wagner et al., 1999; pp. 183-185).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
State of Hawaii Hawaiian Islands	Hawai‘i (Big) Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (pp. 183-184)
State of Hawaii Hawaiian Islands	Kaua‘i Island	introduced invasive	Lorence, David/Flynn, Tim (1999) (p. 3) Voucher cited: D. Jamieson s.n. (PTBG)
State of Hawaii Hawaiian Islands	Lāna‘i Island	introduced invasive	Oppenheimer, Hank L./Bartlett, Randal T. (2002) (p. 2) Voucher cited: Oppenheimer H109916 (BISH)
State of Hawaii Hawaiian Islands	Maui Island	introduced invasive	Oppenheimer, Hank L./Bartlett, R. T. (2000) (p. 1) West Maui. Vouchers cited: Oppenheimer H119810 (BISH), Oppenheimer H119811 (BISH), Oppenheimer H89940 (BISH), Oppenheimer H89909 (BISH)
State of Hawaii Hawaiian Islands	Maui Island	introduced invasive	Starr, Forest/Martz, Kim/Loope, Lloyd L. (2002) (p. 17) East Maui. Vouchers cited: Starr & Martz 000323-1 (BISH), Starr & Martz 000608-1 (BISH)
State of Hawaii Hawaiian Islands	Moloka‘i Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (pp. 183-184)
State of Hawaii Hawaiian Islands	O‘ahu Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (pp. 183-184)
New Caledonia New Caledonia	New Caledonia Islands		Swarbrick, John T. (1997) (p. 88)
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. 11) Vouchers cited: MacKee 16024, MacKee 21692, MacKee 39764
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. 52) Reported from dry lowland areas.
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. 19-20)

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)	Northern Territory	introduced invasive	Smith, Nicholas M. (2002) (p. 57)
Australia Australia (continental)	Queensland	introduced invasive	Smith, Nicholas M. (2002) (p. 57)
China China	Hong Kong	introduced	Wu, Te-lin (2001) (p. 77)
Ecuador (Mainland) Ecuador	Ecuador (Republic of) (continental)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Perú Perú	Perú (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)

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)

Comments:  Prohibited in Western Australia and a declared noxious weed in the Northern Territory (Smith, 2002; p. 57).

Control: 

Physical:  "Manual removal can give effective control if the bulk of the taproot is removed, or if roots are cut well below the soil surface"

Chemical:  "Seedlings can be treated with herbicides containing dicamba.  Established plants are treated with amitrole or picloram herbicides, best applied before flowering occurs"  (Weber, 2003; p. 41).

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

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

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

References:

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.

Lorence, David/Flynn, Tim. 1999. New naturalized plant records for the Hawaiian Islands. In: Evenhuis, Neal L. and Eldredge, Lucius G., eds. Records of the Hawaii Biological Survey for 1998. Part 2: Notes. Bishop Museum Occasional Papers. 59:3-6.

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

Oppenheimer, Hank L./Bartlett, R. T. 2000. New plant records from Maui, O‘ahu, and the Hawai‘i Islands. In: Evenhuis, Neal L. and Eldredge, Lucius G., eds. Records of the Hawaii Biological Survey for 1999. Part 2: Notes. Bishop Museum Occasional Papers. 64:1-10.

Oppenheimer, Hank L./Bartlett, Randal T. 2002. New plant records from the main Hawaiian Islands. In: Evenhuis, Neal L. and Eldredge, Lucius G., eds. Records of the Hawaii Biological Survey for 2000. Part 2: Notes. Bishop Museum Occasional Papers. 69:1-14.

Smith, Nicholas M. 2002. Weeds of the wet/dry tropics of Australia - a field guide. Environment Centre NT, Inc. 112 pp.

Starr, Forest/Martz, Kim/Loope, Lloyd L. 2002. New plant records from the Hawaiian archipelago. In: Evenhuis, Neal L. and Eldredge, Lucius G., eds. Records of the Hawaii Biological Survey for 2000. Part 2: Notes. Bishop Museum Occasional Papers. 69:16-27.

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.

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.

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).

Weber, Ewald. 2003. Invasive plants of the World. CABI Publishing, CAB International, Wallingford, UK. 548 pp.

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

Wu, Te-lin. 2001. Check List of Hong Kong Plants. Hong Kong Herbarium and the South China Institute of Botany. Agriculture, Fisheries and Conservation Department Bulletin 1 (revised). 384 pp.