Basionym Name:Placodium illitum C. Knight, Trans. Linn. Soc. London, Bot., Ser. 2 1(5): 282 (1878)
Homotypic synonyms:Lecanora illita (C. Knight) Forssell, Bih. K. svenska VetenskAkad. Handl., Afd. 3 8(no. 3): 53 (1883)Placopsis illita (C. Knight) I.M. Lamb, Lilloa 13: 266 (1947)