EN
The article deals with the definition problems of the German adjective morphology with nominal reference, generally described as a three-class-system. We pretend to criticize especially the idea of an allomorph concept of congruence, which in our opinion is not able to represent correctly the functionality of the different criteria of application. Actually, even its combination with a quite more realistic vision of the theory of mono-inflexion will not change this impression. We also try to explain didactic consequences, which the traditional scheme of explication might have on learners with a native speaker’s background really based upon the principle of congruence in the mentioned context.