Marginal associations, i.e. floristically impoverished associations at the margin of the distribution area of a higher syntaxon, form a problem in vegetation classification, because true character species are lacking. We propose a new approach for the classification of such marginal associations, making use of the notion of 'chorological tension zones'. In the absence of true character species, the species from other syntaxa of the same formation can be used as such. Our proposal is to use the species group from every formation-true class only once within every marginal alliance, to limit the number of possible marginal associations. This approach is illustrated in a classification of the retamoid thickets in the Netherlands. On the basis of a numerical-subjective classification of the relevant species in the scrub layer and the evaluation of relevant literature, we conclude that the broom and gorse thickets in the Netherlands can be assigned to the Cytisetea scopario-striati Rivas-Mart. 1974, which is represented by four associations, each of which is characterised by the species of other scrub classes. The Ulici europaei-Sarothamnion scoparii Doing ex Weber 1997 is represented by the Rubo plicati-Sarothamnetum scoparii Weber 1987 and the Crataego monogynae-Cytisetum scoparii R. Haveman, I. de Ronde & J.H.J. Schaminée ass. nov., the Ulici europaei-Cytision striati Rivas-Mart., Báscones, Díaz, Fern. Gonz. & Loidi 1991 by the Frangulo alni-Ulicetum europaei De Foucault 1988 and the Rubo ulmifolii-Ulicetum europaei J.-M. Géhu ex R. Haveman, I. de Ronde & J.H.J. Schaminée ass. nov. This classification is based on a restricted dataset though, and a revision, based on a larger dataset from a wider region has to prove the tenability of the classification. ; Die größte Mannigfaltigkeit an retamoiden („Rutenstrauch“-)Gebüschen, zusammengefasst in der Klasse Cytisetea scopario-striati Rivas-Mart. 1974, findet sich auf der Iberischen Halbinsel (COSTA et al. 2003, GAVILÁN et al. 2011, PINTO-GOMES et al. 2012). ...