Phylogenetic and chemotaxonomic resolution of the genus Annulohypoxylon (Xylariaceae) including four new species

Abstract

This study deals with an extensive evaluation focusing on phylogenetic and chemotaxonomic infrageneric relationships of the genus Annulohypoxylon (Xylariaceae, Ascomycota), whose species are ubiquitously associated with seed plants as endophytes and saprotrophs in all forested areas of the world. Using evidence from phylogenetic, chemotaxonomic and morphological data, various varieties within the genus are raised to species level, leading to the new combinations for A. areolatum (≡ A. bovei var. microsporum), A. macrosporum (≡ A. leptascum var. macrosporum), and A. microdiscum (≡ A. moriforme var. microdiscum). Annulohypoxylon substygium nom. nov. is applied for A. stygium var. annulatum and the four new tropical and subtropical species A. massivum, A. violaceopigmentum, A. viridistratum and A. yungensis are introduced. Furthermore, A. leucadendri is excluded from the genus as its morphological characters disagree with the generic concept, the recently erected A. palmicola is synonymized with A. leptascum and A. austrobahiense has been reassigned to the genus Hypoxylon. In addition, the key taxa A. annulatum and A. truncatum have been reinvestigated and epitypes have been defined. For the first time, a dichotomous key to the genus is provided. A phylogenetic β-tubulin tree in conjunction with stromatal HPLC profiles clearly shows that Annulohypoxylon comprises two distinct lineages. The A. cohaerens/multiforme group might eventually warrant segregation into a new genus as further molecular data become available.