Most of the causal agents were polyphagous species that infect many other host plants both overseas and in Australia. All powdery mildews infecting native plants in Australia were phylogenetically closely related to species known overseas. The data indicate that Australia is a continent without native powdery mildews, and most, if not all, species have been introduced since the European colonization of the continent.

Background: Previous phylogenetic analyses of species within the genus Golovinomyces (Ascomycota, Erysiphales), based on ITS and 28S rDNA sequence data, revealed a co-evolutionary relationship between powdery mildew species and hosts of certain tribes of the plant family Asteraceae. Golovinomyces growing on host plants belonging to the Heliantheae formed a single lineage, comprised of a morphologically differentiated complex of species, which included G. ambrosiae, G. circumfusus, and G. spadiceus. However, the lineage also encompassed sequences retrieved from Golovinomyces specimens on other Asteraceae tribes as well as other plant families, suggesting the involvement of a plurivorous species. A multilocus phylogenetic examination of this complex, using ITS, 28S, IGS (intergenic spacer), TUB2 (beta-tubulin), and CHS1 (chitin synthase I) sequence data was carried out to clarify the discrepancies between ITS and 28S rDNA sequence data and morphological differences. Furthermore, the circumscription of species and their host ranges were emended. Results: The phylogenetic and morphological analyses conducted in this study revealed three distinct species named, viz., (1) G. ambrosiae emend. (including G. spadiceus), a plurivorous species that occurs on a multitude of hosts including, Ambrosia spp., multiple species of the Heliantheae and plant species of other tribes of Asteraceae including the Asian species of Eupatorium; (2) G. latisporus comb. nov. (≡ Oidium latisporum), the closely related, but morphologically distinct species confined to hosts of the Heliantheae genera Helianthus, Zinnia, and most likely Rudbeckia; and (3) G. circumfusus confined to Eupatorium cannabinum in Europe. Conclusions: The present results provide strong evidence that the combination of multi-locus phylogeny and morphological analysis is an effective way to identify species in the genus Golovinomyces.

The genus Filipendula comprises about 15 species of perennial herbs distributed in the temperate zone of the Northern Hemisphere (Schanzer, 1994). In the past, Filipendula was treated as a part of the genus Spiraea until its reintroduction as separate genus by Maximowicz (1879). Spiraea is a larger genus of about 80 to 100 deciduous shrub species distributed in the temperate Northern Hemisphere, with a few species in subtropical regions. The highest diversity of Spiraea occurs in Asia, most notably in China (Drábková, Pospíšková, & Businský, 2017). Numerous species are used as popular ornamental shrubs worldwide. Filipendula and Spiraea pertain to the family Rosaceae, but they are not closely allied. Filipendula is a part of the subfamily Rosoideae, but with an isolated position in phylogenetic multilocus analyses, i.e., it does not belong to any tribe (Potter et al., 2007). Spiraea is the type genus of tribe Spiraeeae, which belongs to the subfamily Amygdaloideae (previously Spiraeoideae, Porter et al., 2007;Drábková et al., 2017). Powdery mildews (Erysiphaceae) are common detrimental pathogens on numerous rosaceous host plants. Salmon (1900) assigned powdery mildew on Filipendula vulgaris (as Spiraea filipendula) to Sphaerotheca humuli, followed by Homma (1937), who included Japanese powdery mildews on Filipendula spp. and Spiraea spp. under Sph. humuli. Sawada (1951) described Sph. spiraeae on Spi. thunbergii from Japan. Based on Chinese type material on F. ulmaria, Zhao (1981) introduced the new species Sph. filipendulae. The two species on Filipendula and Spiraea spp. are barely distinguishable morphologically with regard to their asexual or sexual morphs. Therefore, Braun (1987) merged the two species. Later, Braun and Takamatsu (2000) reallocated Sph. spiraeae to Podosphaera. The first comprehensive phylogenetic analysis of powdery mildews on rosaceous hosts suggested that Podosphaera on Filipendula and on Spiraea, although barely distinguishable morphologically, belong to two different clades (Takamatsu, Niinomi, Harada, & Havrylenko, 2010). Based on these results, Braun and Liu (in Liu, 2010) proposed the combination P. filipendulae. A new powdery mildew species, P. filipendulensis, has recently been described from India on F. vestita . The authors compared results of sequence analyses with sequences from P. ferruginea, P. macularis and P. spiraeae, but unfortunately without inclusion of sequences retrieved from P. filipendulae. To clarify the phylogeny, taxonomy, distribution and host range of P. filipendulae, a new

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Broussonetia (Moraceae), distributed in East Asia and on Pacific Islands, comprises four species in China, viz., Broussonetia kaempferi Siebold, B. kazinoki Siebold, B. kurzii (Hook.f.) Corner and B. papyrifera (L.) Vent. Their bark fibres are used for making paper, the woods for furniture, the leaves and fruits for medicinal purposes (Zhou & Gilbert, 2003). Broussonetia spp. have been recorded as hosts of several powdery mildews, viz., Oidium sp., Ovulariopsis sp., Phyllactinia broussonetiae-kaempferi Sawada, Ph. broussonetiaepapyriferae (Sawada) Meeboon & S. Takam. (≡Ovulariopsis broussonetiae-papyriferae Sawada), Ph. guttata (Wallr.