New species of Xerocomus (Boletales) from the Guiana Shield, with notes on their mycorrhizal status and fruiting occurrence.

Xerocomus cyaneibrunnescens, Xerocomus potaroensis, and Xerocomus parvogracilis (Boletales, Basidiomycota) are described as new species from the Pakaraima Mountains of Guyana, in the central Guiana Shield region. These boletes occur in neotropical forests dominated by ectomycorrhizal (ECM) trees in the genus Dicymbe (Fabaceae subfam. Caesalpinioideae). Each species produced basidiomata during a multi-year plot survey, and each was confirmed as an ECM symbiont with one or more leguminous host plant species in Guyana.