The exsiccata 'Dupla Graecensia Lichenum (numbers 1451–1500)' comprises 50 collections (767 specimens) of lichen duplicates from the following 12 countries [the number of taxa is given in square brackets]: Albania (district of Nat [1]), Austria (states of Carinthia [2], Salzburg [3], Styria [12], Tyrol [3], and Upper Austria [10]), Cameroon [2], Canada (pro-vinces of British Columbia [1] and Quebec [1]), France (region Auvergne-Rhône-Alpes [1]), Greece (region of Central Mazedonia [1], islands of Hydra [4] and Rhodes [1]), Italy (regions of Lombardy [1] and Trentino-Alto Adige [1]), Russia (Murmansk Region [1]), Slovenia [1], Sweden (Norrbotten County [1], U.S.A. (states of Alaska [1] and Montana [1]), and Venezuela (state of Mérida [1]). Allographa frischiana and Lecanactis moralesiana are newly described, and the holotype and isotype material is distributed here. In addition, paratype material of Leprocaulon inexpectatum is issued. - TLC-investigations were carried out for 31 species.