Cryptolechia carneolutea is the type species of the genus Cryptolechia, a rare taxon classified as endangered in the UK, now largely confined to ancient Fraxinus trees. The only tree with abundant growth of the species in one of its strongholds, the Slapton Ley National Nature Reserve in Devon, was blown over in a storm in April 2017, making it possible to collect material for molecular studies and transplant specimens to other Fraxinus trees in the area. The results of the phylogenetic analysis revealed C. carneolutea to be nested within the genus Gyalecta (Gyalectaceae). This further supports a broad circumscription of Gyalecta, after also including species previously placed in Belonia and Pachyphiale as proposed in other recent studies. It might be possible to introduce an alternative genus concept in Gyalectaceae, not schematically based on ascoma type and ascospore number, but presently not enough data are available to proceed with such a novel classification. A review of the taxonomic concept of Cryptolechia demonstrates that this name was used inconsistently in the past, and its possible inclusion in Gyalecta was anticipated by other authors. As the majority of species presently classified in Cryptolechia had been placed in Gyalecta before, only five new combinations are required to provide formal inclusion of all taxa in the latter genus: Gyalecta bicellulata (Kalb) D. Hawksw. & Lücking comb. nov., G. caudata (Kalb) D. Hawksw. & Lücking comb. nov., G. pittieriana (Kalb et al.) D. Hawksw. & Lücking comb. nov., G. saxatilis (Vězda) D. Hawksw. & Lücking comb. nov. and G. stellaris (Müll. Arg.) D. Hawksw. & Lücking comb. nov. We also supersede the previous lectotypification of Parmelia carneolutea Turner with the discovery of the holotype specimen in BM.