SUMMARYObservations are presented on the morphology and life histories ofChromastrum kylinoides(Feldm.) comb. nov.,Kylinia rosulataRosenv., andAudouinella pectinata(Kylin) Papenfuss. Each species shows an alternation of dissimilar generations.Although in earlier publicationsC. kylinoidesandK. rosulatahave been confused, andA. pectinatahas been considered conspecific withK. rosulata, it is concluded in the present study that the species are quite different and should be assigned to separate genera.The tetrasporophyte ofC. kylinoidesisChromastrum reductum(Rosenv.) comb. nov.. The tetrasporophyte ofK. rosulatawas indentified asAcrochaetium strictum(Rosenv.) Hamel. The gametophyte ofA. pectinataappears not to have been described as a separate entity from the European coast.A critical evaluation of life histories in the Acrochaetiaceae is supposed to alter the current classifications of the species in this family of red algae.