Catalonia (Spain) | Mediterranean | n.s. | Valley woods, especially alder and ash woods | n.s. | Naturalized | Casasayas 1990 |
Italy | Mediterranean | n.s. | Forest, urban | n.s. | Naturalized | Viegi 1993; Bacchetta et al. 2009 |
Hastings Reservation (California) | Mediterranean | n.s. | n.s. | n.s. | Naturalized | Knops et al. 1995 |
Central Ruhrgebiet (Germany) | Temperate | n.s. | Synanthropic from gardening | n.s. | Casual or naturalized | Keil and Loos 2005 |
Portugal | Mediterranean/Oceanic | 1954 | Established in natural or seminatural communities | n.s. | Naturalized | de Almeida and Freitas 2006 |
Belgium | Maritime temperate | 1972 | n.s. | n.s. | Casual | Verloove 2006 |
Crete | Mediterranean | n.s. | n.s. | n.s. | Naturalized (locally common) | Dal Cin D’Agata et al. 2009 |
Spain | Mediterranean | n.s. | n.s. | n.s. | Naturalized | Sanz Elorza et al. 2011 |
Belgium | Temperate | n.s. | Riparian habitats but also the south-facing, sandy slopes (temporarily wet), (abandoned) and clay quarries, limestone slopes | n.s. | Naturalized (recent spread) | Verloove 2011 |
Southern Poland | Continental | n.s. | Abandoned fields, ploughed field margins, forests | Increase in seed dispersers (Corvus frugilegus and Garrulus glandarius), and land abandonment | Invasive | Lenda et al. 2012, 2018 |
Piešt’any spa town (Slovakia) | Continental | n.s. | Forests (oaks, lime-maples, oak-hornbeams, ash-alder alluvial, shrubs and edges, lanes and ravines, alluvial meadows) | n.s. | Naturalized (abundant) | Medvecká et al. 2012; Uhliarová et al. 2012 |
Czech Republic | Continental | n.s. | Different habitats | n.s. | Naturalized | Pyšek et al. 2012 |
France | Mediterranean | n.s. | n.s | n.s. | Naturalized over a large scale | Filoche et al. 2014 |
Greece | Mediterranean | n.s. | n.s. | n.s. | Naturalized | Galanos 2015 |
Dnipropetrovsk province (Ukraine) | Continental | n.s. | n.s. | n.s. | Naturalized | Baranovski et al. 2016 |