Studies of type specimens and other specimens of Menegazzia subsimilis and M. dissecta have shown that they are referable to the same taxon. Thus, M. dissecta is reduced to synonymy with M. subsimilis, which is characterized by lacerate soralia protruding from lobe apices or vertical lobules (protuberances), small perforations and the presence of the stictic acid complex in the medulla. It has 2-spored asci. The synonymy implies that M. subsimilis has a much wider distribution range than previously known. It is reported here from Oceania (Hawaii, Solomon Islands), Asia (Japan, Papua New Guinea, Russia), Europe (Austria, Germany, Portugal), South America (Ecuador, Peru), the Caribbean (Dominican Republic, Jamaica) and North America (Canada, USA).
