This paper contains a survey of ecological and phytocoenological investigations on maritime vegetation, carried out in the SW Netherlands. After an outline of the nature of the Dutch coasts and of former investigations on salt-marsh vegetation, special attention is devoted to a cybernetic approach to this vegetation and its habitat as realizations in space and time. From an ecological point of view stability and instability in the environment appears to be of essential importance. Starting from this approach estuarine phenomena, the genesis of salt marshes and different physical and chemical properties of the soil (texture, carbonate contents, soil-water relations, salinity and supply of organic matter) are discussed, as well as their connections with some features of the vegetation. Using the same strain of thought, a survey of the vegetation is given, at the same time starting from the principles of classification according to the French-Swiss School of Braun-Blanquet.