XVI International Botanical Congess

The species compositions of powdery mildew fungi parasitizing representatives of Fabales and Rosales are so different, that close relationships of these groups of vascular plants seem to be problematic. Evolution of powdery mildew fungi correlated with evolution of the Fabaceae s.l., and there were at least two main stages in these evolutionary processes: the first occurred long before the phylogenetic divergence of the Caesalpinioideae, Mimosoideae and Faboideae, the second latter stage was connected only with the Faboideae. The first stage resulted in the formation of parasites of legumes from the fungal genera Brasiliomyces, Phyllactinia, Pleochaeta, Uncinula, and partly Erysiphe, species of the Erysiphe-Microsphaera generic group developed at the second stage. Ancestral forms of Erysiphe and Microsphaera species parasitizing the Fabaceae s.l. were probably similar to E. glycines var. lespedezae. The genus Microsphaera is polyphyletic, while the Erysiphe-Microsphaera complex is monophyletic.