The Boletaceae are composed of approximately 26 genera and 415 species (Singer 1986). The family is monophyletic and its species usually have large fleshy basidiomata with a central stipe. The spores are mostly elongate and are produced in tubular or rarely lamellate hymenophores. Around 90% of the members of this family form ectomycorrhizae with several genera of trees in most forest ecosystems. Some species are economically important due to their high value as a food, for example, Boletus edulis, known as porcini mushroom or cèpe.

Phylloporus is somewhat of a morphological oddity in the Boletaceae because its species produce a lamellate rather than tubular hymenophores although other basidioma characters, spore morphology, and chemical and molecular data support the placement of this genus in the Boletaceae. The results of Binder (1999) suggest that Phylloporus is the sister group to the Xerocomus subtomentosus group, species of which produce tubular hymenophores. However, despite several broad-scale phylogenetic studies of the Boletaceae, the phylogenetic relationships of Phylloporus remain unclear. Previous phylogenies of this group include only two species of Phylloporus, one native to Europe and the other to North America. While the majority of Phylloporus species have a tropical distribution, no phylogenetic study of this group has included tropical species.

This work treats twenty-six species from various parts of the world, including 19 tropical taxa. Seven of the species in this work are new to science and two taxa are unnamed. The nomenclature regarding the Phylloporus rhodoxanthus complex is clarified. The phylogenetic analysis here presented includes the largest selection of Phylloporus species in a phylogenetic study to-date. Phylogenetic relationships of selected species of Phylloporus, Xerocomus, and Aureoboletus were estimated using maximum parsimony, maximum likelihood, and Bayesian methods. Those algorithms analyzed sequences of the partial nuclear large subunit ribosomal DNA, the internal transcribed spacer region, and a combined dataset with both genes. Aureoboletus auriporus was used as outgroup for the LSU and the combined dataset. The results suggest that Phylloporus is a monophyletic genus that is separate from the genus Xerocomus.