The - lineage: multilocus phylogenetic analysis and morphology confirm and in the Neotropics.

Many species of exhibit a high phenotypic plasticity. Hence, particularly among them, the morphological species concept remains difficult to apply, resulting in a currently confused taxonomy; as a consequence, the geographical distribution range of many species also remains very uncertain. One of the areas with a strong uncertainty, as far as morphological species concept is concerned, is the Neotropics. It is common that names of species described from other regions, mainly from northern temperate areas, have been applied to Neotropical species. The aim of the present study was to determine which species might lay behind the complex in the Neotropics, using morphological studies and phylogenetic inferences based on both single (ITS) and multilocus (ITS, , and -α) sequences. The results indicated that Steyaert, which is the usually accepted concept for this taxon, was absent from the Neotropics. In this area, Steyaert encompassed at least two phylogenetic species, which are tentatively, for the time being, identified as belonging to and . These two species could be distinguished morphologically, notably by the ornamentation or its absence on their chlamydospores. The results also showed that additional species from the Neotropics might still exist, including, e.g., , but their circumscription remains uncertain until now because of the paucity of material available. Furthermore, it was found that the current concept of embraced a complex of species.