The fungal genus Sabuloglossum (earth tongues) was originally described as a monotypic genus based on the species Geoglossum (Microglossum) arenarium. It typically occupies sandy coastal habitats and forms mycorrhizas with Empetrum nigrum (Ericaceae). While studying material from central Europe (Czech Republic, Slovakia, Austria, and Germany), ascomata morphologically very similar to S. arenarium were observed. They were ecologically limited to mid-altitudinal mountainous habitats and associated with Calluna vulgaris or Vaccinium sp. pl. (Ericaceae). The relationship to S. arenarium and related genera was evaluated using a combination of genetic (nrITS1-5.8S-ITS2 and the 28S nrLSU regions) and comparative morphological analysis. Macro- and micromorphological investigations revealed that mountain populations differ from typical S. arenarium in longer apical cells of paraphyses, more frequently septated ascospores, and the presence of inflated cells in the stipe squamules. In phylogenetic analyses, mountain populations appeared in sister position to S. arenarium in a strongly supported clade. According to these morphological and genetic analyses, in addition to ecological and host-type specificities, the mountain populations from central Europe are proposed here as a distinct species, S. monticola sp. nov. Our study indicates that the speciation of S. monticola may have been driven predominantly by a shift in ecology and mycorrhizal association.