Morphological variation in Sporodictyon is scrutinized in an effort to reconcile it with monophyletic groups based on molecular evidence. Molecular data (nucITS, nucLSU, RPB1) are investigated by Bayesian and parsimony phylogenetic analyses, statistical parsimony, and split decomposition. Morphological variation within and between the monophyletic groups is evaluated. Four monophyletic groups strongly supported by molecular data correspond to morphologically well-characterized species. Sporodictyon schaererianum and S. terrestre are morphologically variable, especially with respect to thallus structure. Two distinct subclades are found in both species, but they could, however, not be distinguished morphologically and may be regarded as cryptic species. A combination of ascoma size, spore pigmentation, spore size and thallus structure characterizes the species recognized, whereas thallus thickness, involucrellum thickness and excipulum pigmentation are found to be quite plastic. A taxonomic revision of Sporodictyon in Northern Europe and the adjacent Arctic is provided, recognizing five species. Two new species, S. arcticum and S. minutum, are described. The name Polyblastia theleodes has been misapplied for S. schaererianum. Several taxonomic synonyms are proposed, particularly for S. terrestre, and lectotypes for several species names are designated