Additions and corrections are provided for the South African species of Graphidaceae tribe Graphideae with hyaline ascospores. Allographa oldayana I. Medeiros sp. nov. is described as new to science based on morphological, chemical and molecular data. The new species is characterized by lirellae with striate labia and a complete thalline margin, a completely carbonized excipulum, large, muriform ascospores, and the presence of hirtifructic acid. Allographa consanguinea (Müll. Arg.) Lücking, A. leptospora (Vain.) Lücking & Kalb, Diorygma aff. minisporum Kalb et al., Graphis crebra Vain., Gr. dupaxana Vain., Gr. furcata Fée, Gr. handelii Zahlbr., Gr. longula Kremp., Gr. pinicola Zahlbr., Gr. proserpens Vain, Gr. subhiascens (Müll. Arg.) Lücking and Platythecium sp. are reported as new records for South Africa. Allographa striatula (Ach.) Lücking & Kalb, Graphis analoga Nyl. and Gr. scripta (L.) Ach. are shown to be misapplied names that should be removed from the South African checklist. The new combination Mangoldia bylii (Vain.) I. Medeiros comb. nov. (bas. Graphis bylii Vain) is made; this represents an earlier name for M. atronitens (A. W. Archer) Lücking et al. Taxonomic notes are provided for Graphis bylii var. lividula Vain. and Gr. denudans Vain., species that are known only from their South African holotypes. Phylogenetic analyses that include new DNA sequence data from the nrLSU, mtSSU and RPB2 loci confirm the generic placements of several species for which molecular data were lacking: Allographa consanguinea, Glyphis atrofusca (Müll. Arg.) Lücking, Graphis crebra and Gr. subhiascens. biodiversity, Graphis pergracilis complex, Northern Mistbelt Forest, savannah, Southern Afrotemperate Forest, taxonomy, tropical lichens