A new species and 2 new records of lichen genus Buellia were discovered from Chuja-do Island in Jeju Province during a recent floristic survey: B. chujana X. Y. Wang, S. Y. Kondr., L. Lőkös & J.-S. Hur sp. nov., B. halonia (Ach.) Tuck., and B. mamillana (Tuck.) W. A. Weber. The new species is characterized by a brown, areolate thallus, the presence of perlatolic acid, and a saxicolous habitat. Together with previously recorded species, 10 Buellia species were confirmed from Jeju-do Island. Among these species, 3 growing in the exposed rocky area contained xanthone (yellowish lichen thallus, UV + orange), indicating that production of xanthone in this genus might be a defense strategy against the harm of UV light. Although the genus Buellia has been thoroughly studied in Korea before, novel species have been discovered continuously, and large species diversity has been found in this crustose genus, even from a small rocky island. This study indicates that the coastal area harbors a vast number of crustose lichen species, and there is great potential to discover unknown lichens in the coastal rocky area in Korea.
Keywords: Coastal area; Lichenized fungi; New species; Taxonomy.