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

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Other Latin names:  Melampodium ruderale Sw.

Common name(s): [more details]

Chinese: li yao jin yao jian

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).

Species:  "Herbs, erect, to 30 cm. Stems glabrate to pilose. Petiole 1-2 cm; leaf blade ovate, 3 (-8) cm, 3-veined from near base, both surfaces pubescent and glandular, base obtuse, acute, or acuminate, margin entire or crenulate-dentate, apex acute or acuminate. Synflorescence terminal, of 2-5 capitula; peduncles slender, pilose, usually longer than capitulum. Capitula discoid, 4-6 mm; phyllaries 2-seriate, outer slightly imbricate, ovate, abaxially pubescent toward base, margin ciliate, apex acuminate or acute, inner paleaceous and involute around florets. Florets 2-6, ca. 2.5 mm; anthers black; style branches lanceolate, pubescent abaxially. Achenes brown, ca. 3 mm, 3-angled, body tuberculate, sparsely setuliferous; pappus an apical peg"  (Flora of China online).

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 (2013)
Cook Islands Southern Cook Islands	Rarotonga Island		McCormack, Gerald (2013)
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)	introduced invasive	U.S. Dept. Agr., Agr. Res. Serv. (2013) Naturalized
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
Australia Australia (continental)	Queensland	introduced invasive	U.S. Dept. Agr., Agr. Res. Serv. (2013) Naturalized
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)	Guatemala (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Central America Central America (Pacific rim)	Honduras (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)
Malaysia Malaysia	Malaysia (country of)	introduced invasive	U.S. Dept. Agr., Agr. Res. Serv. (2013) Naturalized
Singapore Singapore	Singapore (Republic of)	introduced invasive	Chong, Kwek Yan/Tan, Hugh T. W./Corlett, Richard T. (2009) (p. 38) Naturalised
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) Recently naturalized in Taiwan.

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)

Control:  If you know of control methods for Eleutheranthera ruderalis, please let us know.