Five new species of the genus Caloplaca (C. albocrenulata, C. gypsicola, C. renatae, C. subochrochroa and C. wesselsii) and one new Jackelixia-species (J. ottolangei) from the Namib Desert and the adjacent Karoo are described. The type of Caloplaca leucoxantha is investigated. A key of the hitherto known Caloplaca species of the Namib Desert is provided. Keywords: Lichenized Ascomycetes, Caloplaca, Jackelixia, taxonomy, desert biota, Namibia, South Africa.