The anatomical and reproductive adaptations of two closely related lichen species. Caloplaca elegantissima (Nyl.) Zahlbr. and C. namibensis Karnef., sp. nov., occurring in the outer Namib fog desert, are discussed. Both species belong to the cmstose forms, frequently found in the remarkably rich lichen communities, which largely depend on fog precipitation for their water supply. Both species are endemic to the Namib Desert. They are mainly distributed in South West Africa/Namibia but also extend into south-western Angola. The asexual isidiate species. C. namibensis Karnef., is described as new. Keywords: anatomy, Caloplaca elegantissima, C. namibensis, sp. nov., Lichenes, Namib Desert, Teloschistaceae.