The lichenicolous Opegrapha species (Roccellaceae, Ascomycota) with 3-septate ascospores on Pertusaria and Ochrolechia.

The Opegrapha species with 3-septate ascospores growing on Pertusaria and Ochrolechia are revised. Two species are recognized: Opegrapha anomea (of which O. pertusariae, O. quaternella, O. wetmorei and possibly Leciographa weissii are considered to be synonyms), and O. blakii Ertz & Diederich sp. nov. described from a sterile lichen with an Ochrolechia-like thallus, known from Ecuador and Venezuela. Opegrapha anomea and several related lichenicolous species with roundish or irregular, often multilocular ascomata are morphologically intermediate between Opegrapha and Plectocarpon, and might represent a distinct genus. © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society, 2004, 144, 235−241. [ABSTRACT FROM AUTHOR]