Fraxinus ornus L. (C and E-Medit.) – A rare but increasing, locally naturalized escape from cultivation. Apparently first documented in the wild in Belgium as early as 1871 (Verloove 2006). However, the genuine naturalization process probably started only few decades ago. In the 1970’s Fraxinus ornus was already said to be naturalized in the woodland that surrounds the Kolmont castle in Overrepen in Limburg. In the past decades it was also seen in abundance, obviously naturalizing, in, for instance, the Kalkense Meersen in Kalken and the Wolvenberg (Berchem), both nature reserves. Likewise, it is known from coastal dunes in the nature reserve Houtsaegherduinen in De Panne. Although Fraxinus ornus is often found in the immediate surroundings of planted individuals (mostly in urban areas) it is also recorded in fairly remote, more natural habitats, the samaras being easily dispersed by wind and/or water.
Fraxinus ornus belongs to a group of ca. 16 closely similar species (section Ornus), all native to the Old World. In addition to F. ornus several others of these so-called ‘flowering ashes’ are cultivated as ornamentals and could also occur as escapes, for instance F. floribunda Wallich, F. paxiana Lingelsh. , F. sieboldiana Blume and F. lanuginosa Koidz. (e.g. Wallander 2012). Some of these may have been overlooked so far.
Fraxinus ornus often reproduces in high amounts and is regularly considered an invasive species, for instance in riparian habitats (e.g. Thébaud & Debussche 1991, Uribe-Echebarría 2010).
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Selected literature:
Adolphi K. (1995) Neophytische Kultur- und Anbaupflanzen als Kulturflüchtlinge des Rheinlandes. Nardus 2: 272 p.
Baonza Diaz J., Gutierrez Teira A. & Traba Diaz J. (1995) Primeras citas de fresno florido, Fraxinus ornus L., en Burgos. An. Jard. Bot. Madrid 53(1): 128-129. [available online at: https://dialnet.unirioja.es/servlet/articulo?codigo=1419061]
Brandes D. (2006) Zur Einbürgerung von Fraxinus ornus L. in Braunschweig. Braunschweiger naturkundliche Schriften 7(3): 535-544. [available online at: http://digisrv-1.biblio.etc.tu-bs.de:8080/docportal/receive/DocPortal_do...
Laguna Lumbreras E., Guara Requena M. & Curras Cayon R. (1997) Sobre un carácter taxonómico en las poblaciones valencianas de "Fraxinus ornus L.": la heterofilia. Flora Montiberica 6: 60-66. [available online at: http://www.floramontiberica.org/FM/Flora_Monti06.pdf]
Leslie A.C. (2010) Fraxinus ornus (Manna Ash) in Cambridgeshire (v.c. 29). BSBI News 113: 59-60. [available online at: http://archive.bsbi.org.uk/BSBINews113.pdf]
Malos C. (1978) Des données nouvelles concernant la variabilité dans le cadre de l'espèce Fraxinus ornus L. (fam. Oleaceae). Trav. Mus. Hist. Nat. "Grigore Antipa" 19: 237-240.
Molnár Cs. & Czúcz B. (2009) A virágos kőris (Fraxinus ornus L.) terjedése és mai termőhelyei az Északi-középhegységben. Bot. Közlem. 96(1–2): 71–81. [available online at: http://www.botkozlem.elte.hu/en/cont/2009.htm]
Pittoni H. (1980) Ein Neufund von Fraxinus ornus L. in der Steiermark. Notizen Flora Steiermark 5: 29-31. [available online at: http://www.zobodat.at/pdf/NotizenFloraStmk_05_0029-0031.pdf]
Romeo D., Bellini E., Oddo E. & Sajeva M. (2002) Minor veins architecture in Fraxinus ornus leaves. Quad. Bot. Ambient. Appl.12: 91-97.
Schmid M. (2005) Untersuchung zur neophytischen Gehölzflora im Stuttgarter Stadtgebiet. Jh. Ges. Naturkde. Württemberg 161: 178-257.
Thébaud C. & Debussche M. (1991) Rapid Invasion of Fraxinus ornus L. Along the Herault River System in Southern France: The Importance of Seed Dispersal by Water. Journal of Biogeography 18(1): 7-12. [available online at: https://www.researchgate.net/publication/230745833_Rapid_Invasion_of_Fra...
Uribe-Echebarría P.M. (2010) El carácter invasor del fresno de flor (Fraxinus ornus L.) en el norte de la Península Ibérica (Álava y norte de Burgos). Toll Negre 12: 8-15. [available online at: http://www.internatura.org/grupos/apnal/toll_negre12.pdf]
Verloove F. (2006) Catalogue of neophytes in Belgium (1800-2005). Scripta Botanica Belgica 39: 89 p. [available online at: http://alienplantsbelgium.be/sites/alienplantsbelgium.be/files/tabel_2.pdf]
Wallander E. (2012) Systematics and fl oral evolution in Fraxinus (Oleaceae). Belgische Dendrologie Belge 2012: 38-58. [available online at: http://www.oleaceae.info/publications/Wallander2013.pdf]
Wallmann T. & Stingl R. (2011) Die Blumen-Esche Fraxinus ornus am nördlichen Alpenostrand. Neilreichia 6: 183-296. [available online at: http://www.zobodat.at/pdf/NEIL_6_0183-0296.pdf]
Wallnöfer S., Mennel J., Zimmermann J. & Zimmermann S. (2008) Das isolierte Vorkommen von Fraxinus ornus bei Zirl (Nordtirol, Österreich): soziologische Bindung der Art und Beschreibung der Pflanzengesellschaften. Verhandlungen der Zoologisch-Botanischen Gesellschaft in Österreich 145: 49-64. [available online at: http://www.zobodat.at/pdf/VZBG_145_0049-0064.pdf]