The pyrenomycete genusAcanthotheciellaHöhn. is revised to include three species:A. harbata, A. mirabilis, andA. tropicalissp. nov. The form genusYpsiloniais accepted as its conidial state and is shown to belong in the Coelomycetes. Four species are shown to belong inYpsilonia: theYpsiloniastate ofA. barbota, Y. mirabilis, Y. tropicalis, andY. cuspidata. Ypsilonia corticalisWolf is considered as anomen dubium, andY. vagansSpeg. isredisposed in a new genus of Hyphomycetes,Kazulia.