Basionym Name:Umbilicaria muhlenbergii var. diffissa Nyl., [as 'muehlenbergii'] Annls Sci. Nat., Bot., sér. 4 3: 149 (1855)
Homotypic synonyms:Gyrophora diffissa (Nyl.) Nyl., Lich. Fueg. Patag.: 23 (1888)Umbilicaria diffissa (Nyl.) Llano, Monograph of the Lichen Family Umbilicariaceae in the Western Hemisphere: 196 (1950)Umbilicaria dillenii var. diffissa (Nyl.) Nyl., Syn. meth. lich. (Parisiis) 2: 10 (1869)