1. Cytisus multiflorus (L’Hérit.) Sweet (Iberian Peninsula) – A rare, locally naturalised escape from or relic of cultivation. First collected in woodland in Brecht in 1955 (without further details). Discovered in Tilff (Sainval) in 1991 on rocky slopes along a motorway, obviously initially sown for erosion control but now well-established (along with Cytisus striatus and Spartium junceum). Also known since at least 2002 from a coal mine heap in Lanklaar (initially planted but massively reproducing). Occasionally seen elsewhere, for instance on a canal bank of the Albertkanaal in Schoten.
Cytisus multiflorus usually grows on dry and sunny habitats. In its area of origin it is calcifuge and usually occurs in heathlands.
Selected literature:
Galunder R. (1988) Zur Identifikation in Deutschland neu auftretender Cytisus-Arten. Flor. Rundbr. 22(1): 14-17.
Dupont P., Godeau M. & Rivière G. (1984) Remarques sur des espèces ibériques d’ajoncs et de genêts semées au long des routes du Morbihan, de Loire-Atlantique et des territoires voisins. Bull. Soc. Sc. Nat. Ouest de la France N.S. 6(3): 125-129.
Vilks A. (1973) Un genêt a fleurs blanches: Cytisus multiflorus Sweet naturalisé(?)en Haute-Vienne. Bull. Soc. Bot. Centre-Ouest n.s. 4: 40-44.