The floristic composition is studied of the so-called ‘Haf-district’, a region roughly comprising the soils below sea level. The delimitation of this ‘plant-geographical’ region as distinguished by Van Soest (1929) strongly coincides with certain parts of the physical geographical classification by Hof (1983). It is argued here that the term ‘plant-geographical district’ should be changed into ‘floristic district’. The floristic composition of the sea clay soils in the southwestern estuarine region of the country has more resemblance with that of the classical Haf-district than with that of the riverine (‘Fluviatiele’) district. In all, 48 species are typical for the redefined ‘Haf-district’.