Infrageneric classification of the boleticolous genus Sepedonium: species delimitation and phylogenetic relationships

Morphological and anatomical features, pigment chemistry, host specifity and culture behavior were examined for about 200 strains of the boleticolous anamorph genus Sepedonium. A sequence analysis of the internal transcribed spacer region of the nuclear ribosomal RNA genes (including ITS1, 5.8S, ITS2) was performed with 52 of these strains. Phylogenetic trees were generated using neighbor joining and parsimony. The outgroup taxon was Cladobotryum varium. Our DNA data indicate a subdivision of the Sepedonium isolates into eight monophyletic taxa, seven of them assignable to accepted species. Extensive descriptions are provided for all species. One species, S. laevigatum, is described as new. An evaluation is presented for the systematic significance of the characters studied. A morphological key is provided.