COMPATIBILITY GROUPS, SPECIES CONCEPTS AND NOMENCLATURE IN EUROPEAN ARMILLARIA SPECIES

A primarily phenotypic species concept in macrofungi does not necessar ily distinguish 'species' that can only be recognized after compatibil ity experiments. This discrepancy may lead to some taxonomic and nomen clatural problems, as exemplified by the European intersterility group s (ISG) B and E of Armillaria, which have been named A. cepistipes and A. lutea (= A. gallica), respectively. According to morphological cri teria, these taxa can better be united into a single species, A. lutea . The intersterility group (ISG), if determined, can for instance be i ndicated by using the symbols originally used by Korhonen. Thus, we su ggest that suitable citations for A. cepistipes and A. lutea would be A. lutea Gillet ISG B (Korhonen, 1978) and A. lutea Gillet ISG E (Korh onen, 1978), respectively. The nomenclature of taxa, distinguished by incompatibility tests, is necessarily based on a comparison between th e phenotypic characters of these taxa and previous descriptions in the literature. This practice has led to controversies in the nomenclatur e of European Armillaria species. Some remarks on these problems are m ade.