This paper is a contribution to a discussion among Dutch phytosociologists on the concept of “chief formation”, introduced by the author in former publications as a unit in the Braun-Blanquet vegetation system. It is contended that structure should play a major role mainly in the construction of the higher units of classification, floristics in the units of medium rank and species dominance in the lower units. The way in which these criteria can be applied in relation to each other is discussed and demonstrated on some examples of Australian and European vegetation. Special attention is given to the evaluation of dwarf shrub communities, tree savannas and tree and shrub deserts.