Basidiolichen <i>Multiclavula corynoides</i> new to the Czech Republic and a remarkable occurrence of <i>Multiclavula mucida</i> on soil.

This paper reports the first occurrence of basidiolichen Multiclavula corynoides ( Agaricomycetes , Clavulinaceae ) in the Czech Republic, collected in the Šumava Mountains near Železná Ruda. Additionally, we discuss in detail a remarkable find of M. mucida growing atypically on soil in the Šumava foothills. In Europe, three species of Multiclavula are known: M. corynoides , M. mucida , and M. vernalis . Multiclavula mucida is traditionally considered a lignicolous species, typically found on decaying wood in old-growth forests, while M. corynoides is known to inhabit bare soil, often in association with bryophytes. Multiclavula vernalis , a boreo-montane terricolous species, has not yet been recorded in the Czech Republic. The identity of both specimens was confirmed by the nrITS DNA barcode. The discovery of M. mucida on soil is particularly surprising, as substrate type – wood versus soil – often serves as a crucial criterion for distinguishing the species and M. corynoides in widely used identification keys. The paper further discusses the macroscopic and microscopic characteristics of European Multiclavula species, highlighting small inconsistencies in diagnostic features, such as basidiocarp colour and spore dimensions, in various sources. Finally, we provide an identification key to these species.