6. Erigeron sumatrensis Retz. (syn.: E. naudinii (Bonnet) Bonnier, Conyza sumatrensis (Retz.) E. Walker, C. albida Willd. ex Spreng.; incl. Erigeron daveauanus
(Sennen) Greuter) (S-Am.) – A rare but locally commonly naturalised alien. First recorded in 1990 on a coalmine heap in Châtelineau (Lannoy 1990) and in the port of Antwerpen (Lambinon 1991). Very soon spreading and Erigeron sumatrensis soon became a common urban weed in the largest cities in (especially Antwerpen, Brussel and Gent) (Verloove & Boullet 2001). More or less dense concentrations are furthermore known from the surroundings of Kortrijk and in the climatologically favourable coastal areas (Verloove 2006). In Wallonia Erigeron sumatrensis was long confined to the former coal mining area in Hainaut but recently also occurred in and around Liège (especially in the valley of river Meuse). It will surely further extend its distribution range in a near future and probably will become one of the most characteristic urban weeds (locally even surpassing the much earlier introduced Erigeron canadensis).
Erigeron sumatrensis obviously is a thermophilous species and chiefly occupies sun-exposed, dry and often stony habitats: foot of walls, fences, disused railway yards, coalmine heaps, old walls, road verges, railway tracks or canal banks.
Sell & Murrell (2006) recognized Erigeron daveauanus (syn.: Conyza daveauiana Sennen) as a distinct species. It is distinguished by its long, slender, rigidly erect, straight inflorescence branches from low down the stem and involucral bracts 3-4 x 0,4-0,5 mm (versus shorter, stouter branches with a greater tendency to be curved and involucral bracts 4-5 x 0,5-0,6 mm in Conyza sumatrensis s.str.). The former seems to be the most widespread and is probably slightly less thermophilous. However, their distinction is not straightforward (see also Rand 2008) and both are tentatively treated as synonyms here. Rather typical plants of E. daveauanus have recently been detected in the Netherlands, e.g. in Amsterdam (see: http://waarneming.nl/soort/view/722160).
Selected literature:
Anastasiu P. & Memedemin D. (2012) Conyza sumatrensis: a new alien plant in Romania. Botanica Serbica 36(1): 37-40. [available online at: http://www.specii-invazive.ro/system/files/Anastasiu-et-Memedemin-2012-Conyza-sumatrensis-a-new-alien-plant-in-Romania.pdf]
Burton R.M. (1995) The present distribution of Guernsey Fleabane, Conyza sumatrensis, in the London area. London Naturalist 74: 169-176.
Crawley M. (1995) The inexorable spread of Conyza sumatrensis. BSBI News 68: 37.
Lambinon J. (1991) Adventices grainières et autres plantes intéressantes observées en 1990 au port d’Anvers (Belgique). Dumortiera 49: 1-6.
Lannoy M. (1990) Une adventice nouvelle pour la Belgique: Conyza sumatrensis à Châtelineau (province du Hainaut). Nat. Mosana 43: 121-123.
Marshall J.B. (1974) A note on Conyza sumatrensis (Retz.) E. Walker (C. floribunda Kunth). Watsonia 10: 166-167.
McClintock D. & Marshall J.B. (1988) On Conyza sumatrensis (Retz.) E. Walker and certain hybrids in the genus. Watsonia 17: 172-173.
Nesom G.L. (2018) Erigeron floribundus and E. sumatrensis (Asteraceae) in the USA and Mexico. Phytoneuron 2018-27: 1–19. [available online at: http://www.phytoneuron.net/2018Phytoneuron/27PhytoN-Conyzasumatrensis.pdf]
Nesom G.L. (2018) Notes on the occurrence of Erigeron sumatrensis (Asteraceae) in Georgia. Phytoneuron 2018-66: 1–5. [available online at: http://www.phytoneuron.net/2018Phytoneuron/66PhytoN-ErigsumatrensisGeorg...
Pruski J.F. & Sancho G. (2006) Conyza sumatrensis var. leiotheca (Compositae: Astereae), a new combination for a common neotropical weed. Novon 16: 96-101. [available online at: http://www.bioone.org/doi/pdf/10.3417/1055-3177%282006%2916%5B96%3ACSVLC...
Rand M. (2008) Difficulties with Conyza (Fleabanes). BSBI News 108: 40-43.
Reutelingsperger L. (2000) Conyza sumatrensis (Retz.) E. Walker: het begin van de opmars in Nederland? Gorteria26: 224-226.
Sell P. & Murrell G. (2006) Flora of Great Britain and Ireland. Vol. 4 Campanulaceae – Asteraceae. Cambridge University Press, Cambridge: XXVIII + 624 p.
Verloove F. (2002) Ingeburgerde plantensoorten in Vlaanderen. Mededeling van het Instituut voor Natuurbehoud n° 20: 227 p.
Verloove F. (2006) Conyza sumatrensis. In: Van Landuyt W., Hoste I., Vanhecke L., Van den Bremt P., Vercruysse W. & De Beer D., Atlas van de flora van Vlaanderen en het Brussels gewest. Instituut voor Natuur- en Bosonderzoek, Nationale Plantentuin van België en Flo.Wer: 304-305.
Verloove F. & Boullet V. (2001) Conyza bonariensis en Conyza sumatrensis: recent ingeburgerd in België? Dumortiera 77: 2-8. [available online at: https://www.researchgate.net/publication/294142435_Conyza_bonariensis_en...
Vladimirov V. (2009) Erigeron sumatrensis (Asteraceae): a recently recognized alien species in the Bulgarian flora. Phytol. Balcan. 15(3): 361-365. [available online at: http://www.bio.bas.bg/~phytolbalcan/PDF/15_3/15_3_09_Vladimirov.pdf]
Vladimirov V., Matevski V., Bancheva S., Delcheva M., Kostadinovski M. & Ćušterevska R. (2016) First report of Erigeron sumatrensis (Asteraceae) for the flora of the Republic of Macedonia. Fl. Medit. 26: 203-207. [available online at: http://147.163.105.223/flora/26-203.pdf]
Wurzell B. (1988) Conyza sumatrensis (Retz.) E. Walker established in England. Watsonia 17: 145-148.