The present paper gives an account of the taxonomy, nomenclature, ecology and distribution of eleven European species of the lichen genus Cyphelium belonging to Caliciales. Much valuable taxonomical information has been obtained from the study of spore surface structures. These studies have been carried out by light microscopy in combination with transmission and scanning electron microscopy. The last method especially has proved to be a very powerful tool for analyses of surface structures. Interesting correlations are noted between spore surface structures and other taxonomically important features, particularly excipular structure. These correlations suggest the lines for a natural subdivision of the genus, but this will not be undertaken until the Extra-European species have been studied. The chemistry has been studied by thin layer chromatography and in some cases mass spectrometry. The revision of a comprehensive herbarium material seems to have yielded a rather good picture of the distribution of the species.