All-Russian Institute of Plant Protection (VIZR), shosse Podbelskogo 3 Pushkin, St. Petersburg, 196608, Russia

E-mail: [email protected]

Th e current system of the genus Alternaria and allied (alternarioid) hyphomycetes is an invention of intuitive classification based solely on morphological characters. Scrupulous study of the morphology of this group of fungi describes 10 genera consisting of about 370 species. However, contemporary taxonomy does not refl ect the phylogenesis suffi ciently, and approaches to the recognition of species’ borders are void of a population genetic component. Results of phylogenetic analysis revealed that the genus Alternaria, as currently circumscribed by morphology, is paraphyletic, while some allied genera, e.g. Ulocladium and Embellisia, are polyphyletic. At least 19 phylogenetic groups can be resolved well in alternarioid hyphomycetes by molecular markers. Such a division correlates with morphological, physiological and ecological traits. Surprisingly, phylogenetic species of Alternaria in some cases was discovered to include several morphospecies. When systematics of alternarioid hyphomycetes will be adjusted in accordance with genealogic patterns, inevitably generic and species boundaries will have to be changed. It is predicted that new taxa at the ranks of genera and sections will have to be established. However, a tendency in alteration of accepted species number is still unclear.