Racodium Pers. per Fr. 1821 (starting-point date of nomenclature, 1821) has to be typified by Racodium cellare Pers., which makes it a genus of imperfect fungi (Deuteromycetes). Even if Racodium Fr. 1829 is accepted as a genus nomenclatively distinct from Racodium Pers. per Fr. 1821 and as such is referred to the (imperfect) lichens (starting-point date, 1753), it still must be rejected as a later homonym. Zasmidium Fr. 1849 is another name for Racodium Pers. ex. Fr. 1821 and a later synonym of it. For the lichen genus Racodium Fr. 1829 the substitute name Rhacodiopsis Donk, nom. nov. is introduced and for its type species the name Rhacodiopsis rupestris (Pers. per. S. F. Gray) Donk, comb. nov.