The extensive and diverse flora of Braunton Burrows, North Devon, may be attributed to a large extent to the coastal position, favourable climate, wide range of habitat conditions, the low level of soil nutrients and the considerable age of the dune system. The water regime varies from that of dry dunes well above the water table, supporting xerophytes, to wet slacks flooded for much of the year. Severe deficiencies of nitrogen and phosphorus lead to a sparse, open, but species-rich vegetation. Factors influencing the occurrence of a number of rare plants are discussed as well as the spread of some invading species and the effects of the reduction in numbers of rabbits by myxomatosis. Details of the colonization and subsequent development of the vegetation of a slack studied over three decades are given as an example of one type of successional change.