The genusAustraliaena(lichenized Ascomycetes,Physciaceae) with the single speciesA. streimanniisp. nov. is described as new from tropical Australasia. Morphologically it is characterized by crustose thalli with an often radiate-plicate margin, ascospores with a type-B ontogeny, and filiform spermatia. The chemistry of this taxon is diverse (lobaric acid, conlobaric acid, xanthones, gyrophoric acid, lecanoric acid, 5-O-methylhiascic acid, perlatolic acid), and three chemotypes are distinguished.