The "red Hypoxylons" of the temperate and subtropical Northern hemisphere

Selected taxa of  Hypoxylon  from the Northern hemisphere were compared with numerous type and authentic specimens of  H. fuscum ,  H. rubiginosum , and presumably related taxa. Besides morphological analyses, we used secondary metabolite profiles based on high performance liquid chromatography, coupled with diode array detection and mass spectrometry (HPLC-DAD/MS). Chemotaxonomic studies on the Nitschke and Persoon types of the above names and further ancient type specimens turned out to be rather conclusive. Along with the information provided in the world monograph of  Hypoxylon  by Ju and Rogers, the results of our HPLC profiling studies are regarded as key asset to provide a better overview on the diversity and biogeography of these species complexes. The utility of this approach is demonstrated by a study on  Hypoxylon  in the Canary Islands. From a comparison of morphological and chemical traits with the above mentioned material, we recognize two new species ( H. canariense  and  H. urriesii ). The predominantly tropical  H. anthochroum  and  H. subrutilum  were also found from this archipelago, but representatives of these taxa from different parts of the world showed heterogeneous HPLC profiles. The number of accepted species in  Hypoxylon  might increase substantially, once an inventory of their tropical representatives, based on holomorphic morphology and considering the importance of their stromatal extrolites, has been completed.