Verbena bracteata Lag. & Rodr. (syn.: V. bracteosa Michx.) – An exceptional and ephemeral alien. A single individual was recorded in 2016 on bare, stony substrate in an abandoned railway yard in Wondelgem (Gent). In 2018 another individual was observed on sandy soil near a grain storage, also in Gent (port area).
Although relatively weedy, this species has only been rarely recorded in recent times in Europe. It is very locally naturalized in a former military base near Bordeaux in France (You & Peytoureau 2005, Tison & de Foucault 2014). It is also locally established in ports in the valley of river Rhine in Germany, for instance in Mannheim (see Breunig 2004; also: http://www.blumeninschwaben.de/Zweikeimblaettrige/xKleineFamilien/verben...). Ephemeral records are available, for instance, from the British Isles (in a quarry without obvious vector of introduction; Clement & Foster 1994) and Sweden (Karlsson 1997).
Selected literature:
Breunig T. (ed.) (2004) Neue Fundorte – Bestätigungen – Verluste (243-386). Ber. Bot. Arbeitsgem. Südwestdeutschland 3: 67-89. [available online at: http://www.botanik-sw.de/BAS/module/wordpress/wp-content/uploads/2016/04...
Clement E.J. & Foster M.C. (1994) Alien plants of the British Isles. BSBI, London: XVIII + 590 p.
Karlsson T. (1997) Förteckning över svenska kärlväxter. Svensk Bot. Tidskr. 91: 241-560.
Tison J.-M. & de Foucault B. (coord.) 2014) Flora Gallica. Flore de France. Editions Biotope, Mèze : xx + 1196 p.
You C. & Peytoureau J.-Y. (2005) Une nouvelle plante pour la France : Verbena bracteata. Bulletin de la Société Botanique du Centre-Ouest 36: 131-132.