Introduction to Xylariaceous fungi formerly classified as Hypoxylon



Studies in Xylariaceous fungi undertaken during the 19th century have been resumed by modern taxonomists and the knowledge of these fungi has been considerably improved through recent major works. Unfortunately, this literature is usually not easy to read and the amateur mycologists are often reluctant to enter the fascinating world of these lignicolous Pyrenomycetes. On the other hand, on condition that they are able to identify what they collect, amateurs often prove to be able to provide the scientists, who usually lack time for fieldwork, with interesting material or collecting data.

The aim of this work is to present an illustrated taxonomic tool open to amateurs, allowing reliable identification of European Hypoxylon taxa and related genera, and to give ecological data observed in the region prospected by the authors. We hope that, identifying those taxa becoming easier for more mycologists, the knowledge of their taxonomy, distribution and ecological requirements may be improved.

Since its creation by Bulliard in 1791, the concept of Hypoxylon has been used in a very wide sense by various authors and Hypoxylon is an earlier name for many boliniaceous, dyatripaceous or xylariaceous fungi (see Ju and Rogers, 1996, for synonymy).

Until recently, modern authors ( Miller, 1961, Dennis, 1978, Petrini and Müller, 1986, Petrini and Rogers, 1986, Granmo et al., 1989, Mathiassen, 1989) proposed and used a narrower concept, including only xylariaceous fungi having multiperitheciate stromata that are not stalked nor with concentric fibrous rings.

In their recent work of major importance, Ju and Rogers (1996) proposed a narrower delimitation of the genus Hypoxylon Bull., based on stromatal anatomy and pigments and on anamorphs. They followed Pouzar who separated the genera Biscogniauxia Kuntze (1979, 1986) and Nemania S.F. Gray (1985 a, 1985 b) from Hypoxylon and Lćssře and Spooner who reinstated Euepixylon Füisting (1994), and they segregated Creosphaeria Theiss.(1993), Entoleuca Syd.(1996) and Kretszchmaria Fr.(1998).

The Xylariaceae family poses a number of puzzling problems as to evolution, relations with hosts including endophytism, adaptation to dry environments and other ecological aspects, which have drawn attention of L. & O. Petrini (1985), Rogers (1979; 1985; 2000) and Whalley (1996).These authors summarized the current knowledge about taxonomy and ecology of Xylariaceae, but concurrently raised new questions involved by the curious relations of most of members of this family with their hosts.

Additional data about phylogeny and generic delimitations within Xylariaceae were recently brought by molecular studies undertaken by Sánchez-Ballesteros et al. (2000) and Triebel et al. (2005). Results of studies on secondary metabolites and their taxonomic consequencies  are dealt with in a further chapter (Chemotaxonomy).

The present work should be considered as an illustrated complement of the above studies, regarding European taxa.