Phylogeny and taxonomy of the genera of Erysiphaceae, part 8: <i>Podosphaera</i> sect. <i>Tridactyla</i>

The eighth part of a series devoted to the phylogeny and taxonomy of powdery mildews is presented. In this part, the general phylogeny and taxonomy of the genus <i>Podosphaera</i> are treated, including a new division of this genus into sections: <i>Podosphaera</i> sect. <i>Podosphaera, Podosphaera</i> sect. <i>Magnicellulatae</i>, comb. nov. and the reintroduced <i>Podosphaera</i> sect. <i>Tridactyla</i>. Sect. <i>Podosphaera</i> consists of two morphologically deviating subsections (<i>Podosphaera</i> and <i>Sphaerotheca</i>). Subsect. <i>Podosphaera</i> consists of species that have apically dichotomously branched chasmothecial appendages, whereas subsect. <i>Sphaerotheca</i> consists of species with unbranched, mycelioid chasmothecial appendages. These subsections are not monophyletic and thus are based solely on morphology. The phylogeny and taxonomy of species of sect. <i>Tridactyla</i> are treated based on ITS+28S data. New primers for the protein-coding genes glutamine synthetase (<i>GS</i>), RNA polymerase II subunit B (<i>RPB2</i>), and β-tubulin (<i>TUB2</i>) are generated for the genus <i>Podosphaera</i> and provided as a resource for future research. A representative multilocus tree for the entire genus, including all sections, is presented. Additionally, the new combination <i>Podosphaera brayana</i> is introduced. This name has priority over <i>Po. ampla. Erysiphe brayana</i> is lecto- and epitypified, and a lectotype is designated for <i>Sphaerotheca phytoptophila</i>. The present analyses aim to provide resources for future research evaluating powdery mildews of the genus <i>Podosphaera</i> and, in particular, <i>Podosphaera</i> sect. <i>Tridactyla</i>.