Three new Diorygma (Graphidaceae) species from Brazil, with a revised world key.

Three new corticolous Diorygma species are described from Brazil. Diorygma incantatum has transversely 29–31-septate, filiform ascospores 105–108×6 µm, and produces an unidentified substance with Rf 44 in solvent C. Diorygma pauciseptatum produces norstictic and connorstictic acids and has transversely 7–9-septate, I+ blue-violet, large ascospores 28–32×7 µm, surrounded by a gelatinous sheath c. 2 µm wide that is often somewhat expanded at one end. Diorygma tocantinense contains protocetraric acid and has muriform, broadly fusiform ascospores with rounded ends, 24–40×10–15 µm, surrounded by an gelatinous sheath up to c. 5 µm wide that is somewhat expanded at central parts of the ascospore. A revised world key is given to all currently known species of Diorygma. [ABSTRACT FROM PUBLISHER]