Caylusea abyssinica (Fresen.) Fisch. et C.A. Mey. (syn.: Reseda abyssinica Fresen.) (E-Afr.) – A very rare and ephemeral alien. Apparently first recorded in a clearing in woodland in Wolvertem in 1981, possibly from pheasant feed. In 2012 also observed on a demolition site in Overpelt, among numerous birdseed aliens.
There are rather few other alien records of Caylusea abyssinica in western Europe. It was formerly recorded in the port of Rotterdam in the Netherlands (van Ooststroom & Reichgelt 1960) and in the British Isles it has been grown from birdseed waste (Hanson & Mason 1985).
Another species, Caylusea hexagyna (Forssk.) Green, was seen as an alien prior to 1930 in the British Isles (Clement & Foster 1994).
Selected literature: van Ooststroom & Reichgelt (1960), Hanson & Mason (1985), Clement & Foster (1994).