Malcolmia maritima (L.) R. Brown (SE-Eur.) – A rather rare and ephemeral escape from cultivation, M. maritima remained neglected for quite a long time in Belgium. Lambinon (1995) was the first to report about historical Belgian records. It was apparently first collected on waste land in Leuven in 1887 and in Elsene (Brussels) in 1889. In 1902 it was also recorded on the banks of river Vesdre. Then, since the 2nd half of the 20th century, it was slightly increasing. It was seen, for instance, on a dump near Mechelen in 1953, on an old wall in Ninove in 1991 and on stone heaps in Gits in 1992. In the past decades M. maritima has often been sown in wild flower seed mixtures and is now seen most years as an escape from cultivation in various kinds of disturbed habitats, often in urban areas.
The exact identity of the plants found in the horticultural trade is uncertain. According to Tison & de Foucault (2014) the widely cultivated species is M. flexuosa (Sibth. & Sm.) Sibth. & Sm., or perhaps hybrids of it. In M. flexuosa fruiting pedicels are as thick as or broader than fruit base, whereas in M. maritima fruiting pedicels are narrower than fruit base. In plants that were recently observed in Belgium well-developed fruits are rather rarely seen, or not at all. In many cases, however, pedicels seem to be rather thick indeed which may point at M. flexuosa – or even more likely (given poor fruit development) – hybrids of it with M. maritima.
Selected literature:
Lambinon J. (1995) Notes taxonomiques, nomenclaturales et chorologiques relatives à la quatrième édition de la « Nouvelle Flore » de la Belgique et des régions voisines. 3. Données nouvelles sur des plantes adventices ou subspontanées en Belgique. Dumortiera 60: 1-36. [available online at: http://alienplantsbelgium.be/sites/alienplantsbelgium.be/files/dum60%20C...
Stork A.L. (1972) Studies in the Aegean Flora, part 20: Biosystematics of the Malcolmia maritima complex. Opera Botanica 33: 1-118.
Tison J.-M. & de Foucault B. (coord.) (2014) Flora Gallica. Flore de France. Editions Biotope, Mèze : xx + 1196 p.