A revision of European species of Leccinum Gray and notes on extralimital species

This paper deals with the generic delimitation of Leccinum and the taxonomic and nomenclatural implications of the phylogenetic results presented in previous papers by Den Bakker et al. (2004a, 2004b). 28S nrDNA data, used in the past to answer questions concerning genus delimitation of Leccinum, are reanalysed. The phylogenetic inferences based on 28S nrDNA largely coincide with Leccinum sensu Singer. The only species that is excluded from Leccinum is L. eximium. At least one truffle-like genus, Chamonixia, should be included in Leccinum. Morphological characters proposed in the past to delimit the genus are discussed in the light of the phylogenetic results. It is concluded that there is no single diagnostic morphological character that unites species of the genus Leccinum and that a better sampling, and other genes that provide a finer phylogenetic resolution, are needed to reach a final answer about the genus delimitation of Leccinum and other genera in the Boletaceae. The second part of this paper discusses characters used in Leccinum-systematics in the past and contains a revision of the European species of Leccinum with notes on related North American species. Sixteen species are accepted for the European continent, of which one, Leccinum albostipitatum, is described as new to science.