Notes on the identity of Hygrophoropsis rufa (Fungi, Boletales)

Jan Holec1*, Miroslav Kolařík2

1National Museum, Mycological Department, Cirkusová 1740, CZ-193 00 Praha 9, Czech Republic, jan_holec@nm.cz; 2Institute of Microbiology ASCR, Vídeňská 1083, CZ-142 20 Praha 4, Czech Republic; *presenting author

During a mycological study of sandstone gorges in the České Švýcarsko (Bohemian Switzerland) National Park, Czech Republic, a dark-coloured Hygrophoropsis was found and identified as Hygrophoropsis rufa (D.A. Reid) Knudsen. The fungus was described as H. aurantiaca var. rufa D.A. Reid and transferred to the rank of species by Knudsen. Hygrophoropsis rufa is not documented in Czech scientific literature (there are some reports and photographs on the Internet, however lacking important data) and seems to be rare in Europe. In GenBank, there are no sequences of it. Consequently, the Czech collection is described and discussed using both classical and molecular methods. 
The rare fungus Hygrophoropsis rufa is documented from the Czech Republic for the first time. Both classical and DNA study results have proved that H. rufa is a good species, clearly separated from H. aurantiaca. Macroscopically, it differs by an orange-brown to dark brown pileus surface. The stability of the observed differences in spores, being slightly smaller and thick-walled in H. rufa, has to be confirmed using a larger set of collections. A brief comparison with dark-coloured taxa of the group of H. aurantiaca is added. Hygrophoropsis aurantiaca var. atrotomentosa most probably represents a synonym, but its nomenclatural status has to be clarified.