Conyza leucantha (D. Don) Ludlow & Raven, Asteraceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Other Latin names:  Conyza viscidula Wall. ex DC.; Erigeron leucanthus D. Don

Habit:  shrub

Description:  "Annual herbs. Stems erect, 30-150 cm tall, branched, striate, viscid glandular pubescent, especially in inflorescence, later glabrate. Basal and lower leaves withered and deciduous at anthesis, middle cauline leaves elliptic-lanceolate, 5-10 cm long, 1-4 cm wide, apex acute to acuminate, base attenuate, nearly sessile, margins serrate, sparsely puberulous and glandular dotted on both surfaces. Heads numerous, in glomerules terminating stems and branches, 5 mm long, 6 mm across; peduncle 1-9 mm long. Involucre campanulate, bracts 3-seriate, herbaceous, margins scarious, purplish tinged, subequal, linear-lanceolate, 3-4 mm long, densely glandular puberulous and with few eglandular hairs. Ray florets numerous, corolla tubular, filiform, 0.5-1 mm long, lacerate apically; styles 3-3.5 mm long, prominent, nearly equaling pappus, upper part red-purple. Disc florets 5-10, corolla funnelform, ca. 6 mm long, upper part slightly shorter than lower, minutely pubescent just below apex, 5-lobed; lobes and styles sometimes red-purple. Achenes obovate, compressed, 0.5-0.6 mm long, 0.3-0.4 mm wide, sparsely pubescent, glabrate, pale umber. Pappus slightly reddish, bristles numerous, in one row, 4-6 mm long at maturity, deciduous"  (Digital Flora of Taiwan).

"Robust, woody shrub to 2 m high, densely glandular, stems pubescent with rusty hairs.  Leaves lanceolate, 7-10 cm long, 12-18 mm wide, margins minutely toothed, upper surface darker, both surfaces densely covered in minute yellow glandular hairs; sessile.  Inflorescence a rounded panicle; heads broad-campanulate to globose, 5-6 mm long, 5-7 mm diameter; involucral bracts rusty pubescent with paler margins.  Florets reddish; marginal florets many, filiform; inner florets ca 4.  Achenes ovoid, sparsely hairy with thickened margins; pappus of many cream to purplish fine barbellate bristles about 3 mm long" (New South Wales Flora Online).

Habitat/ecology:  In Australia, a "weed of roadsides and disturbed ground" (New South Wales Flora Online).  In Taiwan, "exposed places and roadside slopes at low elevations in the south"  (Digital Flora of Taiwan).

Propagation:  Seed

Native range:  "India, Thailand, southern China, Taiwan, the Ryukyus, the Philippines, Java and Australia"  (Digital Flora of Taiwan).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
New Caledonia New Caledonia	New Caledonia Islands	introduced invasive	Gargominy, Oliver/Bouchet, Philipe/Pascal, Michel/Jaffre, Tanguy/Tourneu, Jean-Christophe (1996) (p. 379) Rudérale, nombreuses localités
Philippines Philippine Islands	Philippine Islands	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Philippines Philippine Islands	Philippine Islands		Merrill, Elmer D. (1923) (p. 601) In old clearings, in thickets, and along trails in ope forests from sea level to 1,800 m.

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	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Australia Australia (continental)	Queensland	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Cambodia Cambodia	Cambodia (Kingdom of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
China China	China (People's Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Indonesia Indonesia	Indonesia (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Japan Ryukyu Islands	Ryukyu Islands	native	Ching-I Peng, ed. (2011)
Taiwan Taiwan	Taiwan Island	native	Ching-I Peng, ed. (2011) "Exposed places and roadside slopes at low elevations in the south".
Vietnam Vietnam	Vietnam (Socialist Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)

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

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

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

References:

Ching-I Peng, ed. 2011. Digital flora of Taiwan (online resource).

Gargominy, Oliver/Bouchet, Philipe/Pascal, Michel/Jaffre, Tanguy/Tourneu, Jean-Christophe. 1996. Conséquences des introductions d'espèces animales et végétales sur la biodiversité en Nouvelle-Calédonie. Rev. Ecol. (Terre Vie) 51:375-401.

Merrill, Elmer D. 1923. An enumeration of Philippine flowering plants, vol. 3 [reprint]. Bureau of Printing, Manila. 628 pp.

National Herbarium of New South Wales. 2006. Flora of New South Wales (online edition).

U.S. Dept. Agr., Agr. Res. Serv. 2011. National Genetic Resources Program. Germplasm Resources Information Network (GRIN). Online searchable database.