Conyza sumatrensis (Retz.) E. Walker, Asteraceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Other Latin names:  Conyza albida Willd. ex Spreng.; Erigeron sumatrensis Retz.

Common name(s): [more details]

Chinese: su men bai jiu cao

English: Guernsey fleabane, broadleaf fleabane, fleabane, tall fleabane

Fijian: matakaro, tho ni papalangi, tho ni vavalangi, thovuka, tumbua, wavuwavu

Tongan: pakaka

Habit:  herb

Description:  "Herbs, annual or biennial, 80-150 cm tall; roots fusiform. Stems erect, thick, branched above middle, densely leafy, densely gray-white strigose, sparsely hirsute. Leaves: basal withered at anthesis, lower cauline petiolate, blade oblanceolate or lanceolate, 6-10 x 1-3 cm, surfaces densely strigose, especially abaxially, base attenuate, margin usually coarsely 4-8-serrate per side, apex acute or acuminate, mid and upper reduced, blade narrowly lanceolate to linear, margin serrate or entire. Capitula 5-8 mm in diameter, numerous, in large and long paniculiform synflorescences; peduncles 3-5 mm. Involucre campanulate to urceolate, ca. 4 x 3-4 mm; phyllaries 3-seriate, gray-green, linear-lanceolate or linear, abaxially scabrous, apex acuminate, outer short or ca. 1/2 as long as inner, inner ca. 4 mm, margin scarious. Ray florets numerous, 4-4.5 mm, lamina yellowish or purplish, short, filiform, apex 2-denticulate; disk florets 6-11, yellowish, ca. 4 mm, tube sparsely puberulent. Achenes linear-lanceoloid, compressed, 1.2-1.5 mm, strigillose. Pappus white, later yellowish brown"  (Flora of China online).

Similar species: Conyza bonariensis

Key to the species (Smith, 1991; pp. 307-308):

C. bonariensis: "Newly exposed receptacles of old heads (2-) 2.5-4.5 mm across, not angular pitted or rarely with 2-3 pits in centre; mature heads 5-6 mm long."

C. sumatrensis:  "Newly exposed receptacles of old heads usually 1.5-2.5 (-3) mm across, angular pitted with projecting points at the angles, sometimes pits and pit margins eroded with age; mature heads 4-5 mm long."

Habitat/ecology:  In Fiji, "from near sea level to 900 m, naturalized on sand dunes and on open hills among ferns and reeds, along roadsides, and in forested areas along streams" (Smith, 1991; pp. 307-308).  In New Zealand, "mostly waste places, also other disturbed sites, coastal areas, forest margins and pasture"  (Webb et al., 1988; 188).

Propagation:  Seed

Native range:  "Indigenous in South America, but now widely adventive; sometimes also considered indigenous in southeastern Asia and Malesia by authors who distinguish Conyza sumatrensis as a distinct taxon.  It was probably an early arrival in Pacific archipelagoes, possibly an inadvertent aboriginal introduction in some areas." (Smith, 1991; pp. 307-308).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
American Samoa Tutuila Islands	Tutuila Island		Swarbrick, John T. (1997) (p. 90)
American Samoa Tutuila Islands	Tutuila Island		Anon. (1988) (p. 1)
Australia (Pacific offshore islands) Lord Howe Island	Lord Howe Island	introduced	Pickard, J. (1984) (p. 205)
Australia (Pacific offshore islands) Lord Howe Island	Lord Howe Island	introduced invasive	Orchard, Anthony E., ed. (1994) (p. 18) Vouchers cited: P.S. Green 1948 (K), A.C. Beauglehole 5645 (MEL), L.A.S. Johnson & A.N. Rodd 1222 (NSW)
Australia (Pacific offshore islands) Norfolk Islands	Norfolk Island	introduced invasive	Orchard, Anthony E., ed. (1994) (p. 8) Vouchers cited: P. Ralston 35 (K); W.R. Sykes NI 927 (CHR); 1889 & 1902, I. Robinson (NSW)
Fiji Fiji Islands	Lakemba Island	introduced invasive	Smith, Albert C. (1991) (pp. 307-308) Voucher cited: Garnock-Jones 927. See comment below.
Fiji Fiji Islands	Matuku Island	introduced invasive	Smith, Albert C. (1991) (pp. 307-308) Voucher cited: Milne 111. See comment below.
Fiji Fiji Islands	Nairai Island	introduced invasive	Smith, Albert C. (1991) (pp. 307-308) Voucher cited: Milne 157. See comment below.
Fiji Fiji Islands	Ngau Island	introduced invasive	Smith, Albert C. (1991) (pp. 307-308) Voucher cited: Milne 206. See comment below.
Fiji Fiji Islands	Ovalau Island	introduced invasive	Smith, Albert C. (1991) (pp. 307-308) Voucher cited: Milne 238. See comment below.
Fiji Fiji Islands	Taveuni Island	introduced invasive	Smith, Albert C. (1991) (pp. 307-308) Voucher cited: Seemann 261. See comment below.
Fiji Fiji Islands	Totoya Island	introduced invasive	Smith, Albert C. (1991) (pp. 307-308) Voucher cited: Milne 73. See comment below.
Fiji Fiji Islands	Vanua Levu Island	introduced invasive	Smith, Albert C. (1991) (pp. 307-308) Vouchers cited: DA 10513, Harwood 94. See comment below.
Fiji Fiji Islands	Vanua Mbalavu Island	introduced invasive	Smith, Albert C. (1991) (pp. 307-308) Voucher cited: Graeffe s. n. See comment below.
Fiji Fiji Islands	Viti Levu Island	introduced invasive	Smith, Albert C. (1991) (pp. 307-308) Vouchers cited: Greenwood 246, Greenwood 410, Smith 4264, Parks 20623, DA 10672, Barclay s. n. See comment below.
Fiji Fiji Islands	Wakaya Island	introduced invasive	Smith, Albert C. (1991) (pp. 307-308) Voucher cited: Milne 375. See comment below.
Japan (offshore islands) Ogasawara (Bonin) Islands	Bonin (Ogasawara) Islands	introduced	Kato, Hidetoshi (2007)
New Caledonia Îles Loyauté (Loyalte Islands)	Île Lifou	introduced invasive	MacKee, H. S. (1994) (p. 34) Voucher cited: Schmid 1000 (NOU)
New Caledonia Îles Loyauté (Loyalte Islands)	Îles Ouvéa (Ouvea Atoll)	introduced invasive	MacKee, H. S. (1994) (p. 34) Voucher cited: Schmid 2304
New Caledonia Îles Loyauté (Loyalte Islands)	Île Tiga	introduced invasive	MacKee, H. S. (1994) (p. 34) Voucher cited: MacKee 45906
New Caledonia New Caledonia Archipelago	Île Grande Terre	introduced invasive	MacKee, H. S. (1994) (p. 34) Vouchers cited: Bourret 703 (NOU), Hoff 921, MacKee 42506
Philippines Philippine Islands	Philippine Islands	introduced invasive	U.S. Dept. Agr., Agr. Res. Serv. (2013) Naturalized
Samoa Western Samoa Islands	Western Samoa Islands		Swarbrick, John T. (1997) (p. 90)
Tonga Tonga Islands	Tonga Islands		Swarbrick, John T. (1997) (p. 90)

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	Queensland Herbarium (2002) (p. 3)
China China	China (People's Republic of)	introduced invasive	Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2013) Common weed of grasslands on slopes, open places, roadsides, streamsides; 100-2500 m. Anhui, Fujian, Gansu, Guangdong, Guangxi, Guizhou, Hainan, Hunan, Jiangsu, Jiangxi, Sichuan, Xizang, Yunnan, Zhejiang.
China China	Hong Kong	introduced invasive	Wu, Te-lin (2001) (pp. 278-279) In wasteland.
Indonesia Indonesia	Indonesia (Republic of)		Waterhouse, D. F. (1993) (p. 65)
Japan Japan	Japan	introduced invasive	U.S. Dept. Agr., Agr. Res. Serv. (2013) Naturalized
Japan Japan	Japan	introduced	Mito, Toshikazu/Uesugi, Tetsuro (2004) (p. 190)
Malaysia Malaysia	Malaysia (country of)		Waterhouse, D. F. (1993) (p. 65)
New Zealand New Zealand	New Zealand (country)	introduced invasive	Webb, C. J./Sykes, W. R./Garnock-Jones, P. J. (1988) (p. 188) As Conyza albida Sprengel
Taiwan Taiwan Island	Taiwan Island	introduced invasive	Ching-I Peng, ed. (2013) "Common in open, waste fields and construction sites from lowlands to 2,000 m".

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. 110)
La Réunion (France) La Réunion Island	La Réunion Island	introduced invasive	MacDonald, I. A. W./Thebaud, C./Strahm, W. A./Strasberg, D. (1991) (pp. 51-61)
Mauritius Mautitius Islands (Mauritius and Rodrigues)	Mauritius Island	introduced invasive	U.S. Dept. Agr., Agr. Res. Serv. (2013) Naturalized

Comments:  Fiji specimens are listed as C. bonariensis by Smith (1991; pp. 307-308), who states that it might be better classified as C. sumatrensis. They are listed here as C. sumatrensis.

Control:  If you know of control methods for Conyza sumatrensis, please let us know.