One of the three lineages found within Oncophorus wahlenbergii Brid. in a recent revision of Scandinavian Oncophorus is explored in detail. Consistent and well-supported nuclear ITS and plastid trnG and rps4 signals for a total of eight specimens belonging to this lineage, and the possibility to recognize its members by morphology, support recognition of Oncophorus demetrii (Renauld & Cardot) Hedenäs, comb. nov. (Dicranum demetrii Renauld & Cardot). This species differs from members of the other two O. wahlenbergii lineages by its more longly and narrowly acuminate leaves, projecting cell walls in the upper leaf margins, and the excurrent costa being rough from projecting cells or cell walls. Contrary to members of the other two O. wahlenbergii lineages, O. demetrii seems to prefer base-rich habitats. Outside Scandinavia, it is at present known from Labrador in Canada. Oncophorus compactus (Bruch & Schimp.) Kindb. is considered a synonym of O. wahlenbergii since Dicranum homannii Boeck, a synonym of O. wahlenbergii, was cited as a synonym of Dicranumvirens var. compactum Bruch & Schimp. when the latter was described.