The definition of the generic limits of Xerocomus s. l. and particularly the delimitation of this genus from Boletus is very unclear and controversial. During his study of European species of the Boletaceae, the author has come to the conclusion that Xerocomus in a wide concept is a heterogeneous mixture of several groups of species. These groups are separated from each other by different anatomical and some other characters. Also recent molecular studies show that Xerocomus s. l. is not a monophyletic group. In agreement with these facts, the European species of Xerocomus s. l. whose anatomy was studied by the present author are here classified into the following, more distinctly delimited genera: Xerocomus s. str., Phylloporus, Xerocomellus gen. nov., Hemileccinum gen. nov. and Pseudoboletus.Boletus badius and Boletus moravicus, also often treated as species of Xerocomus, are retained for the present in the genus Boletus. The differences between Xerocomus s. str., Phylloporus, Xerocomellus, Hemileccinum, Pseudoboletus and Boletus (which is related to this group of genera) are discussed in detail. Two new genera, Xerocomellus and Hemileccinum, and necessary new combinations of species names are proposed.
Šutara J. (2008): Xerocomus s. l. in the light of the present state of knowledge. – Czech Mycology 60(1): 29–62.
