Eleutheranthera ruderalis (Sw.) Sch. Bip., Asteraceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Common name(s): [more details]

Spanish: ogiera

Tongan: pakaka

Habit:  herb

Description: 

Genus:  Annual, erect herbs with opposite, petiolate, simple leaves; flowering heads small, homogamous, discoid, or sometimes heterogamous and radiate, sessile or on short axillary peduncles, solitary or in clusters of 2-4, the phyllaries few, in 1 or 2 series, the inner ones often stramineous, the receptacle bearing keeled, oblong-elliptic, acuminate, scarious, pilose paleae embracing the achenes; ray flowers usually absent or, when present, few, neuter, and with the corolla limb small; disk flowers perfect, fertile, the corolla tubular, 5-lobed, the anther bases sagittate, the style branches linear, acute or acuminate, pilose at apex; achenes narrowly obovoid, somewhat compressed, subangular, narrowed to a small cylindric boss at apex, the pappus absent" (Smith, 1991; pp. 275-276).

Species:  Erect herb to about 75 cm high, with sparse indument; the flowers are yellow, and the achenes are minutely white-puberulent distally.  The species bears a resemblance to Sigesbeckia orientalis"  (Smith, 1991; pp. 275-276).

Habitat/ecology:  Infrequent in Fiji and occurs sparingly in Samoa and Tonga (Smith, 1991; pp. 275-276). In Papua New Guinea, "a weed of roadsides, grazing land, and sometimes cultivation; most often on gravelly soil and in areas of seasonal climate" (Henty & Pritchard, 1975; p. 71). "Occasional to common in cultivated places" (Whistler, 1988; p. 10).

Propagation:  Seed

Native range:  Tropical America, now a widespread weed (Smith, 1991; pp. 275-276).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
American Samoa Manu‘a Islands	Ofu Island		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (1993) (voucher ID: PTBG 41712) Taxon name on voucher: Eleutheranthera ruderalis
American Samoa Tutuila Islands	Tutuila Island		Swarbrick, John T. (1997) (p. 91)
American Samoa Tutuila Islands	Tutuila Island		Anon. (1988) (p. 1)
Cook Islands Northern Cook Islands	Penrhyn (Tongareva) Island		McCormack, Gerald (2011)
Cook Islands Southern Cook Islands	Rarotonga Island		McCormack, Gerald (2011)
Fiji Fiji Islands	Lakemba Island	introduced invasive	Smith, Albert C. (1991) (p. 275) Voucher cited: Garnock-Jones 910
Fiji Fiji Islands	Viti Levu Island	introduced invasive	Smith, Albert C. (1991) (p. 275) Vouchers cited: Greenwood 772A, Greenwood 772, H.B.R. Parham 46
Kiribati Tungaru (Gilbert) Islands	Tarawa Atoll		Swarbrick, John T. (1997) (p. 91) Presence not verified.
Niue Niue	Niue Island	introduced invasive	Whistler, W. A. (1988) (p. 10)
Niue Niue	Niue Island	introduced invasive	Space, James C./Waterhouse, Barbara M./Newfield, Melanie/Bull, Cate (2004) (p. 42)
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. 71) Widely spread at low altitudes.
Papua New Guinea Papua New Guinea (eastern New Guinea Island)	Papua New Guinea (eastern New Guinea Island)		Waterhouse, D. F. (1997) (p. 61)
Samoa Western Samoa Islands	Savai‘i Island		Whistler, W. A. (1988) (p. 10)
Samoa Western Samoa Islands	Upolu Island		Whistler, W. A. (1988) (p. 10)
Solomon Islands Solomon Islands	Solomon Islands		Swarbrick, John T. (1997) (p. 91)
Solomon Islands Solomon Islands	Solomon Islands	introduced invasive	Hancock, I. R./Henderson, C. P. (1988) (p. 71)
Tokelau Tokelau Islands	Tokelau Islands		Waterhouse, D. F. (1997) (p. 61)
Tonga Tonga Islands	Tonga Islands		Whistler, W. A. (1988) (p. 10)
Tonga Tongatapu Group	Tongatapu Island		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (2001) (voucher ID: PTBG 243) Taxon name on voucher: Eleutheranthera ruderalis.
Vanuatu New Hebrides Islands	Vanuatu (Republic of)		Swarbrick, John T. (1997) (p. 91)
Wallis and Futuna Wallis and Futuna (Horne) Islands	Wallis (‘Uvea) Island	introduced invasive	Morat, Ph./Veillon, J.-M. (1985) Morat & Veillon, 1985, cited in Meyer, 2007
Wallis and Futuna Wallis and Futuna (Horne) Islands	Wallis and Futuna Islands		Whistler, W. A. (1988) (p. 10)

Pacific Rim
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Colombia Colombia	Colombia (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Costa Rica Costa Rica	Costa Rica (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Ecuador (Mainland) Ecuador	Ecuador (Republic of) (continental)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Guatemala Guatemala	Guatemala (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Honduras Honduras	Honduras (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Nicaragua Nicaragua	Nicaragua (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Panama Panama	Panama (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Perú Perú	Perú (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Singapore Singapore	Singapore (Republic of)	introduced invasive	Chong, Kwek Yan/Tan, Hugh T. W./Corlett, Richard T. (2009) (p. 38) Naturalised

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. 113)
Australia (Indian Ocean offshore islands) Cocos (Keeling) Islands	Cocos (Keeling) Islands	introduced invasive	Orchard, Anthony E., ed. (1993) (p. 37)

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

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

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

References:

Anon. 1988. Weed list for American Samoa by cropping system. Checklist dated 07/13/88, origin unknown. 3 pp.

Chong, Kwek Yan/Tan, Hugh T. W./Corlett, Richard T. 2009. A checklist of the total vascular plant flora of Singapore: native, naturalised and cultivated species. Raffles Museum of Biodiversity Research, National University of Singapore. 273 pp.

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

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.

McCormack, Gerald. 2011. Cook Islands Biodiversity Database, Version 2007.2. Cook Islands Natural Heritage Trust, Rarotonga.

Meyer, Jean-Yves. 2007. Rapport de mission sur l'Ile d'Uvea (Wallis & Futuna) du 6 au 17 Novembre 2007: Inventaire preliminaire de la flore vasculaire secondaire [unpublished report]. Délégation à la Recherche, Ministère de l'Education, l'Enseignement Supérieur et la Recherche, B.P. 20981 Papeete, Tahiti, Polynésie française. 39 pp.

Morat, Ph./Veillon, J.-M. 1985. Contribution à la connaissance de la végétation et de la flore de Wallis & Futuna. Bull. Mus. Natn. Hist. Nat., Paris, 4e sér., 7, section B. Adansonia 3 : 259-329.

National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.). 2001. Voucher specimen #PTBG243(Tim Flynn 6844).

Orchard, Anthony E., ed. 1993. Flora of Australia. Vol. 50, Oceanic islands 2. Australian Government Publishing Service, Canberra.

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.

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.

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.

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