New and overlooked species from the Galapagos Islands: the generic concept ofDiploiciareassessed

Three new species ofDiploiciaare described from the Galapagos Islands and a fourth,D. glebosa, is transferred fromPyxine; all four are considered endemic to the archipelago. In order to accommodate these species, the generic concept ofDiploiciahas been emended. Two of the species are sterile;D. leproidicais placodioid-leproid, where the thalli derive from pseudocorticate granules aggregating into small, placodioid rosettes with distinctly lobate margins. The second sterile species,D. squamulosa, forms scattered squamules that eventually aggregate into small, placodioid rosettes. The two fertile species,D. glebosa, with an olivaceous to beige, smooth, epruinose upper surface, andD. neotropica, with a white to grey-white, roughened, pruinose upper surface, form larger thalli typical ofDiploicia, have apothecia that are initially lecideine, but are soon engulfed and hidden by a thick thalline margin. Anatomically the proper exciple remains visible for a considerable part of the ontogeny, although it eventually becomes almost completely reduced to a few pigmented or almost hyaline hyphae. This transition from lecideine to lecanorine apothecia is similar to thephysciaeformis-type ontogeny observed in somePyxinespecies. Several species currently accommodated inBuellias. lat. with diploicin and effigurate thalli that lack distinctly lobate margins are discussed and the Socotran endemicPhyscia endopyxineais transferred intoDiploicia.