The African genus Xanthodactylon is circumscribed and compared with the cosmopolitan genus Xanthoria. The two genera are best distinguished by their ascospores. The South African species Xanthodactylon turbinatum is shown to be heterogeneous. A new species Xanthodactylon wirthii is segregated and the new combination X. alexanderbaai is proposed. Four species are thus included in Xanthodactylon. In addition, African species of the genus Xanthoria, X. sipmanii, and the Afro-Eurasian X. monofoliosa, are described and illustrated. A key to the species of Xanthodactylon and morphologically similar species of Xanthoria is presented.