Abstract
The family Nigrofomitaceae has been considered to be a member of Polyporales and a synonym of Polyporaceae for a long time. However, no molecular evidence supports this taxonomic opinion. For the first time, Nigrofomitaceae is included in a phylogenetic analysis, which shows that this family is separated from Polyporales and nested within Hymenochaetales as a distinct lineage from four well-known families, viz. Hymenochaetaceae, Neoantrodiellaceae, Oxyporaceae and Schizoporaceae. Therefore, Nigrofomitaceae is treated as the fifth family of Hymenochaetales. Nigrofomes melanoporus, the type species of Nigrofomitaceae, was considered to have a pantropical distribution. However, from both morphological and phylogenetic perspectives, the Chinese specimens labelled as N. melanoporus are found not to be conspecific with the specimens of N. melanoporus from Costa Rica, close to the type locality in Cuba. These Chinese specimens are thus described as a new species Nigrofomes sinomelanoporus. The species diversity of Nigrofomes in pantropical region is discussed.