Perigrapha Hafellner,
Type : * Perigrapha superveniens (Nyl.) Hafellner [= * Melanotheca superveniens Nyl.]
Description : Lichenicolous, developing on the upper surface of host. Ascomata stromatic, perithecioid, with a kind of ostiole, the ascomatal surface sprinkled with numerous, punctiform holes. Stroma reduced, multilocular, sterile, carbonised stromatic tissue above fertile locules with atra- brown pigment. Hamathecium of netted, branched paraphyses. Asci of Opegrapha -type, clavate to cylindrical, 4-,6-, 8-spored. Ascospores colourless, fusiform, 3-septate, with a distinct, colourless perispore, and with or without an apical appendage.
Perigrapha was recently described as a monospecific genus in the Arthoniales (Hafellner 1996c), being characterised by ascomata that are very similar to those of Plectocarpon (q.v.), but where each fertile locule is perithecioid, with a punctiform ostiole, and ascospores with a hyaline perispore and with or without a long, caudate appendage at one end. One species is known from New Zealand (Ertz et al. 2005).
