Diversity of Chroogomphus (Gomphidiaceae, Boletales) in Europe, and typification of C. rutilus

In this study, eight species of Chroogomphus are recognized from Europe: C. britannicus, C. aff. filiformis 1, C. fulmineus, C. cf. helveticus, C. mediterraneus, C. cf. purpurascens, C. rutilus, and C. subfulmineus. Different candidates for the application of the name C. rutilus are evaluated and the best fit to the description is selected; lecto- and epitypes are chosen to fix the name. Chroogomphus fulmineus and C. mediterraneus are also epitypified and a new species, C. subfulmineus, is described. The infrageneric classification is revised and a new subgenus Siccigomphus and three new sections, Confusi, Filiformes, and Fulminei are introduced. The former sections Chroogomphus and Floccigomphus are elevated to subgeneric level. Comparison of the ITS regions (nuc rDNA ITS1-5.8S-ITS2) of all species studied shows that there is a minimum interspecific difference of 1.5 %, with the exception of the two species belonging to sect. Fulminei which differ by a minimum of 0.9 %. Ecological specimen data indicate that species of Chroogomphus form basidiomes under members of Pinaceae, with a general preference for species of Pinus. Five European species have been recorded under Picea, while Abies and Larix have also been recorded as tree associates, although the detailed nutritional relationships of the genus, involving other suilloid fungi in particular, have yet to be fully clarified.