Conyza canadensis (L.) Cronquist, Asteraceae

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Present on Pacific Islands?  yes

Threat only at high elevations?  no

Other Latin names:  Erigeron canadensis L.

Common name(s): [more details]

English: blood-stanch, butterweed, Canada fleabane, Canadian fleabane, Canadian horseweed, colt's tail, fireweed, flea wort, fleabane, hairy horseweed, hogweed, horseweed, mare's tail, mule tail, pride weed, small-leaf horseweed

Fijian: mandramandra

French: herbe gandi, vergerette du Canada

Hawaiian: lani wela

Japanese: himemukashiyomogi

Spanish: altabaca, canem bord, cola de zorra, hierba del caballo, jarilla, olivarda, venadillo, zamarraga

Habit:  herb

Description:  "A slender erect herb, winter annual or biennial, with a long taproot; stem a few cm to more than 3 m in height, nearly smooth or bristly hairy, unbranched at base, branched near top with many small flower heads; leaves alternate but numerous, often appearing opposite, may be light or dark green depending on habitat, without petioles, basal and lower stem leaves 2.5 to 10 cm long, 1 cm wide, strap-shape, entire or toothed, medium and upper stem leaves smaller, sessile, entire, very narrow, soft hairy at first but becoming harsh on older leaves, some southern Africa types almost glabrous both surfaces but margins rigidly and shortly ciliate; flower heads small, numerous on many short branches at top of stem, about 5 mm in diameter, head or capitulum very fluffy at maturity; involucre composed of  2 or 3 series of very small, pointed, greenish bracts 2.5 to 5 mm long; receptacle flat, 1.2 to 2.5 mm broad when bare, ray florets very short, inconspicuous, usually concealed by slightly longer involucral bracts around each flower, greenish white to lavender, pistillate, more than 100 per head, about as long as disk florets; disk florets numerous, perfect, yellow; fruit a dry indehiscent achene, cylindrical, elongated, broadest above the middle, somewhat tapering toward scar that has attached light-colored collar, apex truncate, surface is longitudinally grooved and has scattered white hairs, color a greenish, yellowish brown, 1.3 mm long by 0.3 mm wide, pappus of 10 or up to 265 hairs, brownish yellow, 1.5 to 3 times longer than achene.  The crushed leaves and other plant parts have the faint odor of carrots" (Holm et al., 1997; p. 228).

"Erect herb to 1" m tall; basal leaves oblanceolate; upper leaves linear, entire, ciliate at base, up to 10 cm long; heads numerous, filiform-pedunculate, in elongated axillary racemes combined into a terminal panicle; involucre 2.5-4 mm long, the bracts somewhat puberulent, with narrow scarious margins and a purplish spical spot; florets rather few, white, very small; achenes smooth, less than 1 mm long, the pappus 3 mm long"  (Stone, 1970; p. 577).

Habitat/ecology:  Especially common on limestone soils on Guam (Stone, 1970; p. 577).  In Hawai‘i, "naturalized in relatively dry, disturbed areas"  (Wagner et al., 1999; pp. 288, 1859).  In Fiji, "from near sea level to 850 m, adventive and sometimes locally common on sandy soils near coast, sand dunes, and open grassy hills, in villages, gardens, and waste places, and along roadsides" (Smith, 1991; pp. 306-307).  In Niue, "a common weed in plantations and elsewhere if the ground is exposed" (Sykes, 1970; p. 64).

Propagation:  Wind-dispersed seed.

Native range:  "Northeastern US to the Caribbean basin and Mexico, widely adventive elsewhere" (Smith, 1991; pp. 306-307).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Commonwealth of the Northern Mariana Islands (US) Northern Mariana Islands	Pagan Island	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 285)
Commonwealth of the Northern Mariana Islands (US) Northern Mariana Islands	Pagan Island	introduced invasive	Fosberg, F. R./Falanruw, M. V. C./Sachet, M.-H. (1975) (p. 42) Voucher cited: Moore 307 (US)
Commonwealth of the Northern Mariana Islands (US) Northern Mariana Islands	Rota Island	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 285)
Commonwealth of the Northern Mariana Islands (US) Northern Mariana Islands	Rota Island	introduced invasive	Space, James C./Waterhouse, Barbara/Denslow, Julie S./Nelson, Duane (2000) (p. Voucher specimen) var. pusilla. Specimen collected: BMW 5813 (BISH, BRI)
Commonwealth of the Northern Mariana Islands (US) Northern Mariana Islands	Saipan Island	introduced	Raulerson, L. (2006) (p. 67)
Commonwealth of the Northern Mariana Islands (US) Northern Mariana Islands	Tinian Island	introduced	Raulerson, L. (2006) (p. 67)
Cook Islands Southern Cook Islands	Ma‘uke Island		McCormack, Gerald (2007) ?
Ecuador (Galápagos Islands) Fernandina Group	Fernandina Island	introduced invasive	Charles Darwin Research Station (2005)
Ecuador (Galápagos Islands) Isabela Group	Volcan Alcedo	introduced invasive	Charles Darwin Research Station (2005)
Ecuador (Galápagos Islands) Isabela Group	Volcan Sierra Negra	introduced invasive	Charles Darwin Research Station (2005)
Ecuador (Galápagos Islands) Santa Cruz Group	Santa Cruz Island	introduced invasive	Charles Darwin Research Station (2005)
Federated States of Micronesia Yap Islands	Ulithi Atoll	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 285)
Federated States of Micronesia Yap Islands	Yap (Waqab) Island		Swarbrick, John T. (1997) (p. 90)
Fiji Fiji Islands	Viti Levu Island	introduced invasive	Smith, Albert C. (1991) (pp. 306-307) var. pusilla. Vouchers cited: DA 11761, DA 11410, Greenwood 1164, DA 2920, Greenwood 921, DA 10672, DA 11329
French Polynesia Society Islands	Moorea Island	introduced	Fosberg, F. R. (1997) (p. 16)
French Polynesia Society Islands	Tahiti Island	introduced	Fosberg, F. R. (1997) (p. 16)
Guam Guam Island	Guam Island	introduced invasive	Stone, Benjamin C. (1970) (p. 577) Vouchers cited: Stone 3788 (GUAM), Stone 4239 (GUAM)
Guam Guam Island	Guam Island	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 285)
State of Hawaii Hawaiian Islands	Hawai‘i (Big) Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 288)
State of Hawaii Hawaiian Islands	Kaho‘olawe Island	introduced invasive	Starr, Forest/Starr, Kim/Loope, Lloyd L. (2006) (p. 32) Var. pusilla (Nutt.) Cronq. Voucher cited: Starr, Starr, Higashino, Bruch & Bryce 050208-2 (BISH)
State of Hawaii Hawaiian Islands	Kaua‘i Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 288)
State of Hawaii Hawaiian Islands	Lāna‘i Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 288)
State of Hawaii Hawaiian Islands	Maui Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 288)
State of Hawaii Hawaiian Islands	Moloka‘i Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 288)
State of Hawaii Hawaiian Islands	Ni‘ihau Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 288)
State of Hawaii Hawaiian Islands	O‘ahu Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 288)
Japan (offshore islands) Bonin (Ogasawara) Islands	Bonin (Ogasawara) Islands	introduced	Kato, Hidetoshi (2007)
Marshall Islands Ralik Chain	Bikini (Pikinni) Atoll	introduced invasive	Whistler, W. A./Steele, O. (1999) (p. 34)
Marshall Islands Ralik Chain	Bikini (Pikinni) Atoll	introduced	Fosberg, F. R. (1988) (p. 15)
Marshall Islands Ralik Chain	Enewetak (Ãnewetak) Atoll	introduced invasive	Whistler, W. A./Steele, O. (1999) (p. 34)
Marshall Islands Ralik Chain	Kwajalein (Kuwajleen) Atoll	introduced invasive	Whistler, W. A./Steele, O. (1999) (p. 34) Vouchers cited: Fosberg 31169, Fosberg 36646, Herbst 8887, Whistler 11248
Marshall Islands Ralik Chain	Kwajalein (Kuwajleen) Atoll	introduced invasive	Fosberg, F. R. (1955) (p. 21) Voucher cited: Fosberg 31169 (US)
Marshall Islands Ratak Chain	Arno Atoll	introduced invasive	Vander Velde, Nancy/Vander Velde, Brian (2007) (p. 5) "Common; ruderal areas".
Marshall Islands Ratak Chain	Majuro (Mãjro) Atoll	introduced invasive	Vander Velde, Nancy (2003) (p. 70)
Marshall Islands Ratak Chain	Majuro (Mãjro) Atoll	introduced	Fosberg, F. Raymond (1990) (p. 38)
Marshall Islands Ratak Chain	Maloelap Atoll		Vander Velde, Nancy (year unknown) Var. pusilla
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. 34) Vouchers cited: MacKee 7986, MacKee 45473, MacKee 45808
Niue Niue	Niue Island	introduced invasive	Sykes, W. R. (1970) (p. 64) Voucher cited: CHR 170429
Niue Niue	Niue Island	introduced invasive	Whistler, W. A. (1988) (p. 9)
Niue Niue	Niue Island	introduced invasive	Space, James C./Waterhouse, Barbara M./Newfield, Melanie/Bull, Cate (2004) (p. 41)
Palau Palau (main island group)	Angaur Island	introduced invasive	Space, James C./Waterhouse, Barbara/Miles, Joel E./Tiobech, Joseph/Rengulbai, Kashgar (2003) (p. 103)
Palau Palau (main island group)	Babeldaob Island	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 285)
Palau Palau (main island group)	Babeldaob Island	introduced invasive	Space, James C./Waterhouse, Barbara/Miles, Joel E./Tiobech, Joseph/Rengulbai, Kashgar (2003) (p. 100)
Palau Palau (main island group)	Peleliu Island	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 285)
Palau Palau (main island group)	Peleliu Island	introduced invasive	Space, James C./Waterhouse, Barbara/Miles, Joel E./Tiobech, Joseph/Rengulbai, Kashgar (2003) (p. 106)
Palau Rock Islands	Ngercheu Island	introduced invasive	Space, James C./Waterhouse, Barbara/Miles, Joel E./Tiobech, Joseph/Rengulbai, Kashgar (2003) (p. 108) Carp Resort
Palau Rock Islands	Ngerchong Island	introduced invasive	Space, James C./Waterhouse, Barbara/Miles, Joel E./Tiobech, Joseph/Rengulbai, Kashgar (2003) (p. 108)
Papua New Guinea Papua New Guinea (eastern New Guinea Island)	Papua New Guinea (eastern New Guinea Island)		Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 226)
Philippines Philippine Islands	Philippine Islands		Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 226)
Tonga Tongatapu Group	Tongatapu Island		Whistler, W. A. (1992) (p. 8) Voucher cited: Soakai 917
United States (other Pacific offshore islands) Midway Atoll	Midway Atoll	introduced invasive	Wagner, Warren L./Herbst, Derral R. (1995) (p. 16) var. pusilla (Nutt.) Cronq.; voucher cited: Herbst & Takeuchi 9072 (BISH)
United States (other Pacific offshore islands) Wake Islands	Wake Island	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 285)
United States (other Pacific offshore islands) Wake Islands	Wake Island	introduced invasive	Fosberg, F. R./Sachet, M.-H. (1969) (p. 15) Vouchers cited: Sachet 897a (US), Fosberg 43536 (US), McFarlane 75 (US), McFarlane 79 (US)

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		Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 226)
Australia Australia (continental)	Queensland		Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 226)
Canada Canada	Canada (country)	native	U.S. Dept. Agr., Agr. Res. Serv. (2007)
Chile (continental) Chile	Chile (Republic of)		Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 226)
China China	China (People's Republic of)		Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 226)
Colombia Colombia	Colombia (Republic of)		Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 226)
Costa Rica Costa Rica	Costa Rica (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2007)
Ecuador (Mainland) Ecuador	Ecuador (Republic of) (continental)		Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 226)
El Salvador El Salvador	El Salvador (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2007)
Guatemala Guatemala	Guatemala (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2007)
Honduras Honduras	Honduras (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2007)
Indonesia Indonesia	Indonesia (Republic of)		Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 226)
Japan Japan	Japan (country)		Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 226)
South Korea South Korea	South Korea (Republic of)		Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 233)
Mexico Mexico	Mexico (United Mexican States)	native	U.S. Dept. Agr., Agr. Res. Serv. (2007)
New Zealand New Zealand	New Zealand (country)	introduced invasive	Webb, C. J./Sykes, W. R./Garnock-Jones, P. J. (1988) (p. 190) "Waste places, dry open gullies".
Nicaragua Nicaragua	Nicaragua (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2007)
Panama Panama	Panama (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2007)
Taiwan Taiwan	Taiwan Island		Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 226)
Thailand Thailand	Thailand (Kingdom of)		Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 226)
Vietnam Vietnam	Vietnam (Socialist Republic of)		Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 226)

Indian Ocean
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
British Indian Ocean Territory Chagos Archipelago	Diego Garcia Island	introduced invasive	Topp, J. M. W. (1988) (p. 9)
Mauritius Mautitius Islands (Mauritius and Rodrigues)	Mauritius Island		Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 226)

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. (2007)

Comments:  var. pusilla in Micronesia (Fosberg et al., 1979; p. 285).

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

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

References:

Charles Darwin Research Station. 2005. CDRS Herbarium records.

Fosberg, F. R. 1955. Northern Marshall Islands Expedition, 1951-1952. Land biota: vascular plants. Atoll Research Bulletin No. 39. Pacific Science Board, National Academy of Sciences, Washington. 22 pp.

Fosberg, F. R. 1988. Vegetation of Bikini Atoll. Smithsonian Institution, Washington. Atoll Research Bulletin 315:1-28.

Fosberg, F. R. 1997. Preliminary checklist of the flowering plants and ferns of the Society Islands. Ed. by David R. Stoddart. U. Cal. Berkeley.

Fosberg, F. R./Falanruw, M. V. C./Sachet, M.-H. 1975. Vascular flora of the northern Marianas Islands. Smithsonian Contrib. Bot. 22:1-45.

Fosberg, F. R./Sachet, M.-H. 1969. Wake Island vegetation and flora, 1961-1963. Atoll Research Bulletin No. 123. Smithsonian Institution, Washington. 15 pp.

Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce. 1979. A geographical checklist of the Micronesian dicotyledonae. Micronesica 15:1-295.

Fosberg, F. Raymond. 1990. A review of the natural history of the Marshall Islands. Atoll Research Bulletin No. 330. Smithsonian Institution, Washington. 100 pp.

Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James. 1997. World weeds: natural histories and distribution. John Wiley & Sons. 1129 pp.

Kato, Hidetoshi. 2007. Herbarium records of Makino Herbarium, Tokyo Metropolitan University. Personal communication.

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

McCormack, Gerald. 2007. Cook Islands biodiversity and natural heritage. On-line database.

Raulerson, L. 2006. Checklist of Plants of the Mariana Islands. University of Guam Herbarium Contribution 40:1-69. .

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.

Space, James C./Waterhouse, Barbara/Denslow, Julie S./Nelson, Duane. 2000. Invasive plant species on Rota, Commonwealth of the Northern Mariana Islands.  USDA Forest Service, Honolulu. 31 pp.

Space, James C./Waterhouse, Barbara/Miles, Joel E./Tiobech, Joseph/Rengulbai, Kashgar. 2003. Report to the Republic of Palau on invasive plant species of environmental concern. USDA Forest Service, Honolulu. 174 pp.

Starr, Forest/Starr, Kim/Loope, Lloyd L. 2006. New plant records from the Hawaiian Archipelago. In: Evenhuis, Neal L. and Eldredge, Lucias G., eds. Records of the Hawaii Biological Survey for 2004-2005. Part 1: Articles. Bishop Museum Occasional Papers 87:31-43.

Stone, Benjamin C. 1970. The flora of Guam. Micronesica 6:1-659.

Swarbrick, John T. 1997. Weeds of the Pacific Islands. Technical paper no. 209. South Pacific Commission, Noumea, New Caledonia. 124 pp.

Sykes, W. R. 1970. Contributions to the flora of Niue. New Zealand Department of Scientific and Industrial Research Bulletin 200, Wellington. 321 pp.

Tassin, Jacques. 2005. Jacques Tassin (IAC-CIRAD), personal communication.

Topp, J. M. W. 1988. An annotated check list of the flora of Diego Garcia, British Ocean Territory. Atoll Research Bulletin No. 313. Smithsonian Institution, Washington. 21 pp.

U.S. Dept. Agr., Agr. Res. Serv. 2007. National Genetic Resources Program. Germplasm Resources Information Network (GRIN). Online searchable database.

Vander Velde, Nancy. 0. Nancy Vander Velde, pers. com.

Vander Velde, Nancy. 2003. The vascular plants of Majuro Atoll, Republic of the Marshall Islands. Smithsonian Institution, Atoll Research Bulletin No. 503:1-141.

Vander Velde, Nancy/Vander Velde, Brian. 2007. Arno plants [preliminary working listing of plant species]. Unpublished checklist, 13 pp.

Wagner, Warren L./Herbst, Derral R. 1995. Contributions to the Flora of Hawai‘i. IV. New Records and name changes. In: Evenhuis, Neal L. and Miller, Scott, E., eds. Records of the Hawaii Biological Survey for 1994. Part 2: Notes. Bishop Museum Occasional Papers. 42:13-27.

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).

Webb, C. J./Sykes, W. R./Garnock-Jones, P. J. 1988. Flora of New Zealand, Volume IV: Naturalised pteridophytes, gymnosperms, dicotyledons. Botany Division, DSIR, Christchurch. 1365 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.

Whistler, W. A. 1992. Flora of Tonga [unpublished checklist]. 107 pp.

Whistler, W. A./Steele, O. 1999. Botanical survey of the United States of America Kwajalein Atoll (USAKA) Islands. Prepared for Oak Ridge Institute for Science and Education and the U. S. Army Environmental Center. 111 pp.