In 1975 two specimens of O. crocata were found in the dunes of Voorne. Since then the number increased to c. 50. The species is described and compared to other umbelliferous species, as it is likely to be mistaken for Petroselinum crispum or Apium graveolens vegetatively. Different observations on the smell of the plant and the colour of its juice are mentioned. The plant is virulently poisonous, which is illustrated with some references from literature. Its Atlantic-Westmediterranean area (fig. 2) has been reconstructed from literature and herbarium collections; somewhat uncertain is a record from Morocco. From an old collection its presence along the Northwest-coast of Italy could be confirmed. The habitats in Voorne, Normandy and Jersey are described and compared, also with records from other localities. At the localities in the northern part of France and in Holland it grows in coastal habitats characterized by a considerable seepage of fresh water rather rich in carbonates.