Abstract During the examination of fungal material collected in Romania in 2019, two novel taxa within the genus Geoglossum were identified and classified: G. lepidum and G. squamulosum . These taxa were ecologically restricted to alluvial habitats on the stabilized riverbed deposits. Both species produce relatively small ascocarps, G. lepidum is characterized by a black fertile part and a brown stipe with an olivaceous tint. At the same time, G. squamulosum exhibits a distinct scaly stipe surface. The delimitation of these species was based on a combination of unique morphological characteristics and molecular phylogenetic analyses using nuc rDNA ITS1-5.8S-ITS2 (ITS) and nuc 28S rDNA (LSU) regions. Despite pronounced macroscopic differences, microscopic features of both taxa are structurally similar, with primary distinctions observed in the dimensions of key anatomical traits. Phylogenetic inference places these species in close relationship with G. calciphilum , G. dunense , G. infatum , and G. vleugelianum , within a clade characterized by ascospores with predominantly seven septa. Comparative morphological analyses are presented to distinguish the newly described species from closely related taxa. Additionally, a comprehensive list of surveyed localities and the macrofungal species encountered during the study is included in the supplementary file.
Kučera et al. (2026) studied this question.