Salvinia natans is a warm .cmperatc species still living in Europe (Map 1). Up to 1936 it was only known from Pleistocene interglacial deposits. Florschutz and Jonker (1936) first mentioned it in 1936 in post-glacial deposits; only one macrosporangium was found in the Holocene underneath the Cathedral Square at Utrecht. In 1939 the same authors discovered large amounts of macro- and microsporangia in an Old Atlantic clay near Wijk bij Duurstede (Map 2). According to Godwin (1956), up to that year these were the only occurrences known from the west European Post-Glacial.