ABSTRACT Collema leptosporum was originally included in Collemataceae as part of the Collema fasciculare group, an informal group that also included C. fasciculare, C. papuanorum, and C. uviforme. However, molecular data from C. fasciculare showed that this species belongs to Arctomiaceae, and all species in this informal group were relocated to Arctomia, although no molecular data were generated and analyzed for C. leptosporum, C. papuanorum and C. uviforme. To investigate the phylogenetic relationships of Collema leptosporum, currently Arctomia leptospora, we analyzed three DNA loci and examined morphological and anatomical features of specimens collected near the type locality. Genetic data suggest that this species is not included in Arctomiaceae and should be treated as a new genus in Collemataceae. Hondaria gen. nov. is characterized by having the longest transversely-septate ascospores in the family ((100-)120-175(-200) × 2-4(-5) µm). This study also suggests that the structures characterizing the C. fasciculare group are a result of convergent evolution, since this group includes species from different distantly related species.