Phylogenetic study of Hypoxylon and related genera based on ribosomal ITS sequences

Hypoxylon, with at least 130 currently accepted species and varieties, is o ne of the largest genera of the Xylariaceae. Taxonomic aspects that define and delimit the genus have varied among mycologists. To obtain insight in t he phylogenetic relationships of Hypoxylon and its allies, the complete DNA sequences of the internal transcribed spacer region (including the 5.8S rR NA gene) from 41 isolates were determined, aligned and processed for phylog enetic reconstruction, and critically compared with the available taxonomic information. The results generally agree with the current concepts and lim its established for the genus. The molecular approach supported the recent segregation of some allied genera (Biscogniauxia, Camillea, Whalleya, Creos phaeria, Nemania, and Kretzschmaria) from Hypoxylon. The species and variet ies of Hypoxylon in the sense of modern authors appeared as a monophyletic group within the Xylariaceae. However the recent infrageneric division of H ypoxylon into sections Hypoxylon and Annulata was not supported by this lim ited molecular phylogenetic analysis. Likewise, this preliminary analysis d id not reflect generic distinctions among species in genera with bipartite stromata (Camillea and Biscogniauxia). The importance of the anamorphs in t he classification of this fungal group was evidenced by the correlation bet ween the type of anamorph and the relative placement of the teleomorphs in the phylogenetic tree derived from sequence analysis.