Molecular phylogeny of Caloboletus (Boletaceae) and a new species in East Asia

Caloboletus has recently been erected to accommodate Boletus calopus and its allies. Our phylogenetic analyses based on four gene markers (ITS, nrLSU, tef1-alpha and rpb1) recognized six distinct species within the genus. Morphologically, the genus is characterized by the combination of the yellow hymenophore, smooth spores that are olive-brown in deposit, an interwoven pileipellis, a bluish color-change and a distinctly bitter taste of the context. A new species was described and a key to the six species of Caloboletus is provided. Members of Caloboletus are mainly distributed in subtropical and temperate zones in the Holarctic and are often associated with plants of Pinaceae and Fagaceae.