Contributions to the lichen genus Cresponea (Roccellaceae)

Abstract Two Tasmanian species of the genus Cresponea are treated: C. graemeannae Kantvilas sp. nov., characterized by a very thin, saxicolous thallus, apothecia with a thick, radially fissured margin, thinly pruinose disc, hypothecium inspersed with oil droplets, and 5–9-septate ascospores, 25–40 × 6–8 μm; and C. subpremnea (Kantvilas & Vĕzda) Kantvilas comb. nov. The latter has ascospores 30–58 × 4.5–7 μm, which distinguish it from the related C. plurilocularis (Nyl.) Egea & Torrente (ascospores 27–45 × 6–8 μm). The taxa are illustrated, discussed and compared. Cresponea litoralis Elix, based on an Australian type, is considered a synonym of Bactrospora myriadea (Fée) Egea & Torrente. A key to the species of Cresponea reported from Australia is presented.