Geoglossum simile of North America and Europe: Distribution of a widespread earth tongue species and designation of an epitype

Geoglossum simile is a distinctive species of the earth tongue class Geoglossomycetes, first described in 1873. The taxonomic standing of this species has long been disputed, resulting in nearly 70 years of potential misdiagnoses. Although G. simile was originally described from North America, it has subsequently been reported from several European countries as well as Asia, Australasia, and India. In this study, we report the first records of G. simile from Slovakia and the Czech Republic, examine the morphological and molecular diversity of Northern Hemisphere collections, discuss the taxonomic history and current status of the species, and designate a recent North American collection as the epitype of this widely distributed and conservationally significant species.