Flaveria trinervia (Spreng.) C.Mohr, Asteraceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Other Latin names:  Flaveria australasica Hook.; Oedera trinervia Spreng.

Common name(s): [more details]

English: clustered yellowtops, speedyweed, yellow twinstem

Habit:  herb

Description:  "Taprooted annual herbs 1.5-8 (-20) dm tall, puberulent or subglabrous; stems often purplish, divaricately branched.  Leaves lanceolate, oblanceolate to elliptic or narrowly ovate, 3-15 cm long, (0.7-) 1-4 cm wide, distinctly 3-nerbed from base, margins subentire to serrate-dentate, petioles of principal leaves 1-2 cm long, petiole bases nearly connate, upper leaves sessile and usually connate.  Heads with a single floret, aggregated into secondary head-like clusters ca. 1 cm in diameter the common receptacle thus formed with scattered bristles ca. 1/2 as long to as long as primary heads, secondary heads subtended by a few leafy bracts, heads radiate or discoid, radiate heads usually peripheral in secondary heads, the central ones usually discoid; involucre of primary heads of 1-2 bracts, 3-4.5 mm long; rays pale yellow or whitish, 0.5-1 mm long; disk corollas 2-2.5 mm long; pappus absent.  Achenes 2-2.6 mm long"  (Wagner et al., 1999; p. 317).

Habitat/ecology:  "A widespread tropical and subtropical weed; in Hawai‘i sparingly naturalized in strand vegetation and coastal sites" (Wagner et al., 1999; p. 317).

Propagation:  Seed

Native range:  The Americas; naturalized elsewhere (GRIN).

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	Kaho‘olawe Island	introduced invasive	Herbst, Derral R./Wagner, Warren L. (1996) (pp. 9-10) Voucher cited: Ellshoff 196 (BISH)
State of Hawaii Hawaiian Islands	Kaua‘i Island	introduced invasive	Lorence, David H./Flynn, Timothy W./Wagner, Warren L. (1995) (p. 24) Voucher cited: T. Flynn et al. 3186 (BISH, F, MO, PTBG, US)
State of Hawaii Hawaiian Islands	Kure Atoll	introduced invasive	Starr, Forest/Starr, Kim/Loope, Lloyd L. (2010) (p. 62) Voucher cited: Starr & Starr 010522-02 (BISH)
State of Hawaii Hawaiian Islands	Maui Island	introduced invasive	Oppenheimer, Hank L. (2003) (p. 7) West Maui. Vouchers cited: Oppenheimer H80108 (BISH, PTBG), Starr & Martz 000204-1 (BISH), Oppenheimer H100044 (BISH, PTBG), Oppenheimer H40135 (BISH, PTBG)
State of Hawaii Hawaiian Islands	O‘ahu Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 317) Voucher cited: Engler 37-232 (BISH)

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)	New South Wales	introduced invasive	U.S. Dept. Agr., Agr. Res. Serv. (2013) Naturalized
Australia Australia (continental)	Australia (continental)	introduced invasive	U.S. Dept. Agr., Agr. Res. Serv. (2013) South Australia, Western Australia Naturalized
Australia Australia (continental)	Northern Territory	introduced invasive	U.S. Dept. Agr., Agr. Res. Serv. (2013) Naturalized
Australia Australia (continental)	Queensland	introduced invasive	U.S. Dept. Agr., Agr. Res. Serv. (2013) Naturalized
Mexico Mexico	Mexico (United Mexican States)	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) Arequipa
United States (west coast) United States (west coast states)	USA (California)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)

Indian Ocean
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Mauritius Mautitius Islands (Mauritius and Rodrigues)	Mauritius Island	introduced invasive	U.S. Dept. Agr., Agr. Res. Serv. (2013) Naturalized

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 Flaveria trinervia, please let us know.