Scrophularia canina L. (Medit.) - A very rare and probably ephemeral alien. Recorded on two occasions in 2019. First seen in cracks of pavement in Nismes (a single individual, eradicated soon after its discovery). Subsequently, two tall, richly flowering and fruiting specimens were seen in a coal storage area in the Ghent port area. In the latter locality a local naturalization is not unlikely.
Scrophularia canina is naturalized on coalmining spoil heaps in parts of northwestern France, relatively close to the Belgian frontiers (see Verloove & Lambinon 2014 for further details). It seems to steadily spread towards northern Europe and its future occurrence in Belgium was anticipated.
This species is characterized by its pinnatisect leaves and is unmistakable. However, it is quite variable and rather numerous infraspecific taxa have been described. The plants seen in Ghent have strikingly bicolored corollas (due to the conspicuous white margins of the lobes). Such plants have been separated as subsp. bicolor (Sibth. & Sm.) W. Greuter (syn.: S. bicolor Sibth. & Sm.), a variant from southeastern Europe (Richardson 1972), but probably of limited taxonomic value.
Selected literature
Verloove F. & Lambinon J. (2014) The sixth edition of the Nouvelle Flore de la Belgique: nomenclatural and taxonomic remarks. Dumortiera 104: 7-40. [available online at: http://www.br.fgov.be/DUMORTIERA/DUM_104/Dum_104_7-40_NF-6_Taxonomy_Nome...
Richardson I.B.K. (1972) Scrophularia. In: Tutin T.G. & al. (eds.), Flora Europaea, vol. 3. Cambridge University Press, Cambridge: 216-220.