Platythecium seychellense, a new species in the family Graphidaceae (lichenized Ascomycota: Ostropales) from the Seychelles and a world key to the genus.

The new corticolous lichen fungus Platythecium seychellense is described from the Seychelles. Morphological characters as well as distribution and resemblance to related species are discussed. The species is characterized by a crustose, grey-green, smooth thallus lacking lichen substances, elongate and slender apothecia having flat, red-brown discs and grey 3-septate ascospores. A world key to all currently known species in the genus is presented. [ABSTRACT FROM AUTHOR]