Caloplaca lucifuga Thor sp. nov. is described and reported from Denmark, England, France, Germany, Italy and Sweden. It is only found sterile and is mainly characterized by its endophloedic, sorediate thallus, chemistry and habitat. In Sweden, the species is found in dense wooded pastures dominated by Quercus robur, growing on the bark of very old trunks of Quercus robur or, rarely, Tilia cordata. Outside Sweden, it is found also on Castanea sativa, Fagus sylvatica and Ulmus glabra.