Six new Graphidaceae (lichenized Ascomycota: Ostropales) from Horton Plains National Park, Sri Lanka

Based on new collections of Graphidaceae originating from Horton Plains National Park in Sri Lanka, six new species are described: Chapsa thambapanni Weerakoon, Jayalal & Lucking, differing from C. laemensis in the larger ascomata and ascospores produced in numbers of 2-4 per ascus; Fissurina lumbschiana Weerakoon, Jayalal & Lucking, differing from F. consentanea in the larger, comparatively short, gaping ascomata; F. tuberculifera Weerakoon, Jayalal & Lucking, differing from F. insidiosa in the tuberculate thallus and the larger, more emergent ascomata with tuberculate margins, as well as the amyloid ascospores and psoromic acid chemistry; Graphis mahaeliyensis Weerakoon, Jayalal & Lucking, differing from G. subintermedians in the single-spored asci with larger ascospores; Thelotrema heladiwense Weerakoon, Jayalal & Lucking, differing from T. weberi and T. subweberi in the transversely septate ascospores and presence of a unique, unknown secondary compound; and Topeliopsis subtuberculifera Weerakoon, Jayalal & Lucking, differing from T. tuberculifera in the large, basally constricted thallus verrucae, the substipitate ascomata with bumpy margins and wider pore, and the narrower ascospores. The rather unique lichen biota encountered in the Horton Plains National Park, as exemplified by these new taxa, underlines the recognition of this area as one of the world heritage sites in Sri Lanka. Nevertheless, further extensive field work is necessary to document the overall lichen biota in the park.