Mycoscience (2008) 49:185–191 DOI 10.1007/s10267-008-0406-8 © The Mycological Society of Japan and Springer 2008 FULL PAPER Susumu Takamatsu · Hayato Masuya Rangsi Divarangkoon · Yukihiko Nomura Erysiphe fimbriata sp. nov.: a powdery mildew fungus found on Carpinus laxiflora Received: August 1, 2007 / Accepted: January 7, 2008 Abstract Ascomata of a powdery mildew-like fungus have been found on Carpinus laxiflora in Tochigi Prefecture of Japan since 2003. The morphological and molecular characteristics of this fungus are reported, and a new species, Erysiphe fimbriata, is proposed. It has large chasmothecia (200–250 µm in diameter) with long (up to 4–5 mm in length), fimbriate appendages arising from the upper half of the chasmothecia and turning upward, and numerous asci (22–38 per chasmothecium). Erysiphe fimbriata is a unique fungus both genetically and morphologically. Key words Betulaceae · Erysiphaceae · Erysiphales · Molecular phylogeny · New species Introduction The family Betulaceae (Fagales) is composed of six genera and up to 130 species of anemophilous shrubs and trees. Most species of the family are distributed in temperate regions of the Northern Hemisphere, i.e., Asia, Europe, and North America (Chen et al. 1999). More than 50% of the total species of the Betulaceae have been reported as hosts of powdery mildew fungi (Amano 1986). Because the ratio of hosts of powdery mildew fungi among the total species S. Takamatsu (*) Graduate School of Bioresources, Mie University, 1577 Kurimamachiya, Tsu 514-8507, Japan Tel. +81-59-231-9497; Fax +81-59-231-9540 e-mail: takamatu@bio.mie-u.ac.jp H. Masuya Forest Pathology Laboratory, Forestry and Forest Products Research Institute, Ibaraki, Japan R. Divarangkoon Department of Plant Pathology, Faculty of Agriculture, Chiang Mai University, Chiang Mai, Thailand Y. Nomura Yotsukaido, Chiba, Japan of angiosperms is about 4.5% (Amano 1986), this high ratio of hosts in the Betulaceae may indicate a close evolutionary affinity of this plant family with the powdery mildew fungi. Carpinus is one of the six genera of the Betulaceae (including Corylaceae), which is distributed in Asia, Europe, and North America, with a divergence center in China. Six species, i.e., Erysiphe carpinicola (Hara) U. Braun & S. Takam. [= Uncinula carpinicola (Hara) Hara], E. ellisii (U. Braun) U. Braun & S. Takam. (= Microsphaera ellisii U. Braun), E. pseudocarpinicola (Y. Nomura & Tanda) U. Braun & S. Takam. (= U. pseudocarpinicola Y. Nomura & Tanda), E. wuyiensis (Z.X. Chen & R.X. Gao) U. Braun & S. Takam. [= U. wuyiensis (Zhi X. Chen & R.X. Gao) U. Braun], Oidium carpini Foitzik, and Phyllactinia guttata (Wallr.) Lév., have been reported to occur on Carpinus (Braun 1987, 1995; Braun and Takamatsu 2000). Recently, E. carpinicola was divided into three species, E. arcuata U. Braun, Heluta & S. Takam. (host: C. betulus L. and C. tschonoskii Maxim.; anamorph: O. carpini), E. carpinicola (host: C. japonica Blume), and E. carpini-laxiflorae U. Braun, Heluta & S. Takam. [host: C. laxiflora (Siebold & Zucc.) Blume] based on morphological and molecular characteristics (Braun et al. 2006, 2007). Thus, a total of seven species of the powdery mildew fungi occur on Carpinus now. In March 2003, we found powdery mildew-like ascomata attached to fallen twigs of C. laxiflora in litter of the Mikamoyama Park, Sano-shi, Tochigi Prefecture, Japan (see Fig. 3), which appeared to be strange because powdery mildew fungi are obligate biotrophs of plants. They usually infect living host tissues, and do not have saprophytic life stages. However, both morphological observations and a molecular phylogenetic analysis indicated that this fungus is a member of the powdery mildews. In this study, we report the morphological and molecular characteristics of this fungus that is described as a new species of the powdery mildew fungi with a unique morphology. 186 Materials and methods Morphological studies Specimens on C. laxiflora were examined by standard light microscopy (Axio Imager; Carl Zeiss, Göttingen, Germany) and differential-interference-contrast optical instruments and devices. The specimens examined are deposited at MUMH (Herbarium, Faculty of Bioresources, Mie University, Tsu, Japan), TNS (Herbarium of the National Museum of Nature and Science, Tsukuba, Japan), and HAL [Martin-LutherUniversity, Institute of Biology, Geobotany and Botanical Garden, Herbarium, Halle (Saale), Germany]. Molecular phylogenetic study MUMH 3694, a paratype specimen of Erysiphe fimbriata, was used for molecular analysis. Isolation of whole-cell DNA was performed using the chelex method (Walsh et al. 1991) as described in Hirata and Takamatsu (1996). The 5′-end of the 28S rDNA, including the domains D1 and D2, and the internal transcribed spacer (ITS) region, including the 5.8S rDNA, were amplified by polymerase chain reaction (PCR) and then sequenced using direct sequencing as described in Takamatsu et al. (2006). DNA sequences determined in this study were deposited in DDBJ (DNA databank of Japan) under the accession numbers of AB333839. The sequences were initially aligned using the Clustal X package (Thompson et al. 1997). The alignment was then visually refined with a word processing program, using colour-coded nucleotides. The alignments were deposited in TreeBASE (http://www.treebase.org/) under the accession number of S1942. Phylogenetic trees were obtained from the data using the maximum-parsimony (MP) method in PAUP* 4.0 (Swofford 2001) and Bayesian analysis in MRBAYES 3.1.1 (Huelsenbeck and Ronquist 2001). MP analyses were performed with the heuristic search option using the tree-bisection-reconstruction (TBR) algorithm with 100 random sequence additions to find the global optimum tree. All sites were treated as unordered and unweighted, with gaps treated as missing data. The maximum tree number was set as 104. The strength of the internal branches of the resulting trees was tested with BS analyses using 1000 replications with the stepwise addition option set as simple (Felsenstein 1985). Bootstrap (BS) values higher than 70% are provided. For Bayesian phylogenetic analyses, the best-fit evolutionary model was determined for each data set by comparing different evolutionary models via the Akaike information criterion (AIC) using PAUP* and MrModeltest 2.2 (Nylander 2004). MRBAYES was launched with random starting trees for 106 generations and the Markov chains were sampled every 100 generations, which resulted in 104 sampled trees. To ensure that the Markov chain did not become trapped in local optima, we used the MCMCMC algorithm, performing the estimation with four incrementally heated Markov chains. Of the resulting 104 trees, the first 2000 (burn-in) were discarded. The remaining 8000 trees were summarized in a majority-rule consensus tree, yielding the probabilities of each clade being monophyletic. Bayesian posterior probability (PP) values higher than 0.95 are provided. Results Field observation The occurrence of powdery mildew on C. laxiflora was observed from June to December 2006 in the Mikamoyama Park. No powdery mildew occurrence was found in early June. White powdery mildew colonies were found on the leaves of C. laxiflora in late September. The powdery mildew mainly colonized veins and their surrounding areas of the lower surface of leaves, and caused necrotic discolorations and distortions of the attacked host tissues. Colonies were not found on the upper leaf surface. Young, immature chasmothecia were produced on the colonies. In late October, mature chasmothecia were observed on the colonies together with immature ones. Long (up to 4–5 mm in length), fimbriate appendages rose from the upper half of the chasmothecia, which were easily observable by naked eye (see Fig. 4). By early December, almost all leaves had fallen on the ground. Obvious white colonies with mature chasmothecia were observed on the fallen leaves, but infections of twigs were not found during this period. Conidial formation was also not observed. Phylogenetic placement of Carpinus powdery mildew in the Erysiphaceae: 28S rDNA analysis A total of 99 sequences of 28S rDNA, including a sequence from the new Carpinus powdery mildew, were used to construct the phylogenetic tree of the Erysiphaceae. Byssoascus striatisporus (G.L. Barron & C. Booth) Arx (Myxotrichaceae) was used as an outgroup taxon, based on Mori et al. (2000). The data set consisted of 831 characters, of which 245 characters were variable and 189 characters were phylogenetically informative for parsimony analysis. A total of 104 equally MP trees with 995 steps (CI = 0.3789, RI = 0.8014, RC = 0.3037) were constructed by the MP analysis. To avoid the possibility that the heuristic search became trapped in local optima, we repeated similar analysis by the parsimony ratchet method (Nixon 1999) using PAUPRat (Sikes and Lewis 2001). The analysis also generated trees with 995 steps having topologies similar to the MP trees. Thus, one of the 104 MP trees is shown in Fig. 1. Most internal branches are supported in the strict consensus of the 104 trees. Bayesian analysis generated similar tree topology. The previous phylogenetic analyses of the Erysiphaceae demonstrated that five tribes and two basal genera are included in the family (Mori et al. 2000; Braun and Erysiphe quercicola ex Quercus AB197135 Erysiphe quercicola ex Quercus AB292691 Erysiphe quercicola ex Quercus AB292694 Erysiphe heraclei ex Daucus AB022391 28S rDNA Erysiphe friesii ex Rhamnus AB022382 Erysiphe nomurae ex Symplocos MUMH 275 99 sequences Erysiphe monascogera ex Styrax MUMH 3786 831 characters Erysiphe alphitoides ex Quercus AB292699 Erysiphe alphitoides ex Quercus AB292707 995 steps Erysiphe alphitoides ex Quercus AB237811 96 Erysiphe alphitoides ex Quercus AB257431 CI = 0.3789 Erysiphe sp. ex Quercus AB292712 Erysiphe sp. ex Quercus AB292711 RI = 0.8014 Erysiphe hypophylla ex Quercus AB292715 Erysiphe hypophylla ex Quercus AB292716 RC = 0.3037 Erysiphe abbreviata ex Quercus AB271785 84 Erysiphe hypogena ex Quercus AB292725 Erysiphe hypogena ex Quercus AB292727 82 Erysiphe hypogena ex Quercus AB292726 Erysiphe epigena ex Quercus AB292718 Erysiphe epigena ex Quercus AB292717 Tribe Erysiphe epigena ex Quercus AB292720 1.0 Erysiphe epigena ex Quercus AB292722 Erysipheae Erysiphe aquilegiae ex Cimicifuga AB022405 Erysiphe pulchra ex Swida AB022389 Erysiphe paeoniae ex Paeonia AB257438 93 Erysiphe carpinicola ex Carpinus AB252469 Erysiphe carpinicola ex Carpinus AB252467 100 Erysiphe carpinicola ex Carpinus AB252468 1.0 Erysiphe sp. ex Carpinus AB252464 Erysiphe carpi-laxiflorae ex Carpinus AB252472 100 .99 .97 Erysiphe carpi-laxiflorae ex Carpinus AB252471 1.0 Erysiphe carpi-laxiflorae ex Carpinus AB252470 Brasiliomyces trina ex Quercus AB022350 Erysiphe simulans ex Rosa AB022395 Erysiphe gracilis ex Quercus AB022357 73 Typhulochaeta japonica ex Quercus AB022415 1.0 Erysiphe mori ex Morus AB022418 100 Erysiphe pseudocarpinicola ex Carpinus AB252465 1.0 Erysiphe pseudocarpinicola ex Carpinus AB252466 96 Erysiphe glycines ex Desmodium AB022397 MUMH3694 Carpinus laxiflora Erysiphe arcuata ex Carpinus AB252463 Erysiphe arcuata ex Carpinus AB252474 Erysiphe arcuata ex Carpinus AB252473 Erysiphe adunca ex Salix AB022374 Erysiphe australiana ex Lagerstroemia AB022407 86 Golovinomyces orontii ex Veronica AB077651 Golovinomyces sordidus ex Plantago AB077657 Golovinomyces orontii ex Rubia AB077634 87 77 Golovinomyces orontii ex Nicotiana AB022412 Golovinomyces adenophorae ex Adenophora AB077632 Golovinomyces orontii ex Physalis AB077646 96 1.0 98 Golovinomyces cichoracearum ex Dahlia AB077628 Golovinomyces cichoracearum ex Aster AB077641 79 1.0 Golovinomyces cichoracearum ex Eupatorium AB022387 Tribe 1.0 Golovinomyces cichoracearum ex Solidago AB077650 100 Arthrocladiella mougeotii ex Lycium AB329690 Golovinomyceteae 1.0 Arthrocladiella mougeotii ex Lycium AB022379 92 Neoerysiphe galeopsidis ex Lamium AB329674 Neoerysiphe galeopsidis ex Chelonopsis AB022369 83 Neoerysiphe galeopsidis ex Acanthus AB329670 100 1.0 Neoerysiphe galii ex Galium AB329681 1.0 Neoerysiphe galii ex Galium AB329682 75 Oidium maquii ex Aristotelia AB329686 98 Oidium aloysiae ex Aloysia AB329683 1.0 Neoerysiphe cumminsiana ex Cacalia AB329669 Oidium baccharidis ex Baccharis AB329684 100 Oidium phyllanthi ex Phyllanthus AB120755 Oidium subgen. 100 1.0 Oidium phyllanthi ex Phyllanthus AB120754 1.0 Microidium Oidium phyllanthi ex Phyllanthus AB120758 94 Phyllactinia guttata ex Alnus AB080452 98 Phyllactinia guttata ex Euptelea AB080388 1.0 75 Phyllactinia guttata ex Morus AB080372 1.0 100 Phyllactinia guttata ex Diospyros AB022372 78 Tribe Phyllactinia guttata ex Hamamelis AB080410 1.0 .97 99 Phyllactinia fraxini ex Fraxinus AB080451 100 Phyllactinieae Phyllactinia fraxini ex Syringa AB080436 .95 1.0 Leveillula taurica ex Artemisia AB080470 98 Leveillula guilanensis ex Chondrilla AB080478 Leveillula saxaouli ex Haloxylon AB080469 1.0 Pleochaeta turbiana ex Platycyamus AB218773 .99 Pleochaeta shiraiana ex Celtis AB022403 99 Podosphaera longiseta ex Prunus AB022423 71 Podosphaera tridactyla ex Prunus AB022393 98 .99 1.0 Podosphaera xanthii ex Melothria AB022410 1.0 92 Podosphaera pannosa ex Rosa AB022347 Tribe 100 1.0 Podosphaera filipendulae ex Filipendula AB022384 Cystotheceae 100 Sawadaea polyfida ex Acer AB022364 1.0 82 1.0 Sawadaea tulasnei ex Acer AB022366 73 100 Cystotheca wrightii ex Quercus AB022355 .99 Cystotheca lanestris ex Quercus AB022353 1.0 Blumeria graminis ex Hordeum AB022399 100 Tribe Blumerieae Blumeria graminis ex Triticum AB022376 1.0 Blumeria graminis ex Bromus AB022362 100 Parauncinula septata ex Quercus AB022420 1.0 Parauncinula septata ex Quercus AB183533 Basal group Caespitotheca forestalis ex Schinopsis AB193467 Byssoascus striatisporus U17912 73 5 changes Fig. 1. Phylogenetic analysis of the divergent domains D1 and D2 sequences of the 28S rDNA for 99 sequences from the Erysiphaceae covering all known tribes and one outgroup taxon. The tree is a phylogram of the maximum-likelihood tree among the 104 most parsimonious trees with 995 steps, which was obtained by a heuristic search employing the random stepwise addition option of PAUP*. Gaps were treated as missing data. Horizontal branch lengths are proportional to the number of nucleotide substitutions that were inferred to have occurred along a particular branch of the tree. Percentage bootstrap support (1000 replications; >70%) and posterior probability (>0.95) are shown on and under branches, respectively 188 Takamatsu 2000; Takamatsu et al. 2005a,b). The present analysis supports the monophyly of four tribes, i.e., the tribes Blumerieae, Erysipheae, Cystotheceae, and Phyllactinieae. The tribe Golovinomyceteae groups with Oidium subgenus Microidium To-anun & S. Takam. (To-anun et al. 2005) to form a clade together. Caespitotheca S. Takam. & U. Braun and Parauncinula S. Takam. & U. Braun take basal positions within the Erysiphaceae. The fungus MUMH 3694 on C. laxiflora is placed in the genus Erysiphe DC. and groups with E. pseudocarpinicola (= Uncinula pseudocarpinicola) from C. cordata Blume and E. glycines F.L. Tai var. glycines from Desmodium podocarpum DC. subsp. oxyphyllum (DC.) Ohashi, but this is supported by neither BS nor PP values. tive for parsimony analysis. A total of 106 equally MP trees with 639 steps (CI = 0.5540, RI = 0.7209, RC = 0.3994) were constructed by the MP analysis. A tree with the highest likelihood score among the 106 MP trees is shown in Fig. 2. Most internal branches are supported in the strict consensus of the 106 trees. Bayesian analysis generated similar tree topology. The ITS sequence from MUMH3694 on C. laxiflora is sister to all Erysiphe species excluding E. australiana (McAlpine) U. Braun & S. Takam. (= U. australiana McAlpine) and E. adunca (Wallr.) Fr. var. adunca [= U. adunca (Wallr.) Lév. var. adunca], but this is supported by neither BS nor PP values. Phylogeny within Erysiphe: ITS analysis Taxonomy A total of 31 ITS sequences from Erysiphe, including a sequence from the new Carpinus powdery mildew, were used to construct the phylogenetic Erysiphe tree. The data set consisted of 711 characters, of which 212 characters were removed from the analysis because of ambiguous alignment. Of the remaining 499 characters, 225 characters were variable, and 161 characters were phylogenetically informa- Erysiphe fimbriata S. Takam., Masuya & Y. Nomura, sp. nov. Figs. 3–9 MycoBank no.: MB511033 Mycelio hypophyllo, in venis et prope venas habitanti, hyalino, persistensi; discolorationem cum necrose et torsionem folii efficienti; chasmotheciis hypophyllis, dispersis vel subgregariis, fusco-brunneis, 200–250 µm diametro; peridiis Fig. 2. Phylogenetic analysis of the nucleotide sequences of the internal transcribed spacer (ITS) region including 5.8S rDNA for 31 sequences from Erysiphe. The tree is a phylogram of the maximum-likelihood tree among the 106 most parsimonious trees with 639 steps, which was obtained by a heuristic search employing the random stepwise addition option of PAUP*. Gaps were treated as missing data. This tree is also the maximumlikelihood tree among the 106 most parsimonious trees. Horizontal branch lengths are proportional to the number of nucleotide substitutions that were inferred to have occurred along a particular branch of the tree. Percentage bootstrap support (1000 replications; >70%) and posterior probability (>0.95) are shown on and under branches, respectively Erysiphe arcuata ex Carpinus AB252463 Erysiphe arcuata ex Carpinus AB252473 Erysiphe arcuata ex Carpinus AB252474 100 Erysiphe pseudocarpinicola ex Carpinus AB252466 1.0 Erysiphe pseudocarpinicola ex Carpinus AB252465 Erysiphe glycines ex Desmodium AB015927 Erysiphe heraclei ex Daucus AB000942 97 1.0 Erysiphe friesii ex Rhamnus AB000939 1.0 Erysiphe aquilegiae ex Cimicifuga AB000944 Erysiphe japonica ex Swida AB000941 Erysiphe carpinicola ex Carpinus AB252469 100 Erysiphe carpinicola ex Carpinus AB252467 1.0 100 Erysiphe carpinicola ex Carpinus AB252468 77 1.0 Erysiphe sp. ex Carpinus AB252464 100 Erysiphe togashiana ex Styrax AB091775 1.0 Erysiphe carpi-laxiflorae ex Carpinus AB252472 100 Erysiphe carpi-laxiflorae ex Carpinus AB252471 1.0 Erysiphe carpi-laxiflorae ex Carpinus AB252470 Typhulochaeta japonica ex Quercus AB022416 Brasiliomyces trina ex Quercus AB022351 .98 Erysiphe gracilis ex Quercus AB022358 Erysiphe wadae ex Fagus AB091776 Erysiphe simulans ex Rosa AB015926 92 Erysiphe flexuosa ex Aesculus AB091774 1.0 Erysiphe prunastri ex Prunus AB046983 Erysiphe mori ex Morus AB000946 Erysiphe necator ex Vitis AF073346 MUMH3694 Carpinus laxiflora 100 Erysiphe adunca ex Populus AF011324 1.0 Erysiphe adunca ex Salix D84383 Erysiphe australiana ex Lagerstroemia AB022408 10 changes ITS 31 sequences 499 characters 639 steps CI = 0.5540 RI = 0.7209 RC = 0.3994 100 1.0 189 Figs. 3–8. Erysiphe fimbriata. 3 Chasmothecia attaching on a twig of Carpinus laxiflora. 4 Long, fimbriate appendages growing upward from leaf surface. 5 Chasmothecia with long appendages. 6 Anchoring hyphae arising from whole surface of young, immature chasmothecia. 7, 8 Asci and ascospores. Bars 3–7 100 µm; 8 20 µm ex cellulis angulatis vel irregularibus 20–25 × 15–17.5 µm compositis; appendicibus ex parte superne chasmothecii oriundis, surgentibus, (17–)20–50, simplicibus, mycelioidibus, rectis, interdum sinuosis vel geniculatis, interdum torulosis, raro ramosis, (3–)4–8(–12.5) µm latis, 4–5 mm longis, septatis, crassitunicatis, hyalinis, raro ad basim pallide brunneis; hyphis anchoriformibus ex superficie omnino chasmothecii oriundis, intertextis; ascis numerosis, 22–38, pedunculatis, 75–105 × 35–37.5 µm, ellipsoideis vel ovoideis; ascosporis 6–8, late ellipsoideis vel ovoideis, hyalinis, 20–25 × 12.5–17.5 µm. Typus: Japan, Tochigi Prefecture, Sano-shi, Mikamoyama Park, on fallen leaves of Carpinus laxiflora (Siebold & Zucc.) Blume (Betulaceae), 4 Dec 2006, leg. S. Takamatsu (Holotypus, TNS-F-16170; isotypus, MUMH 4592 and HAL 2051 F). Etymology: “fimbriata” refers to the long, fimbriate appendages. 190 MUMH 4303; 22 Oct 2006, leg. S. Takamatsu, Y. Shiroya, and M. Ito, MUMH 4416. Discussion Fig. 9. Erysiphe fimbriata. A Chasmothecium. B Peridial cells. C Appendages. D Asci and ascospores. E Ascospores. Bars A 100 µm; E 20 µm (for B–E) Mycelia hypophyllous, colonizing veins and the surrounding leaf area, hyaline, persistent, causing necrotic discoloration and distortion of the attacked host tissue. Chasmothecia hypophyllous, scattered to subgregarious, blackish brown, 200–250 µm diameter, peridial cells angularirregular in outline, 20–25 × 15–17.5 µm. Appendages (17–) 20–50, arising from the upper part of chasmothecia, turning upward, simple, mycelioid, straight, sometimes slightly sinuous to geniculate, sometimes having small projections, rarely branched, (3–)4–8(–12.5) µm wide, long (up to 4– 5 mm), aseptate, thick-walled, hyaline, rarely pale brown at the base. Anchoring hyphae arise from whole surface of chasmothecia, interwoven with vegetative hyphae. Asci numerous, 22–38 per chasmothecium, stalked, 75–105 × 35–37.5 µm, ellipsoid to ovoid, (6–)8-spored. Ascospores broadly ellipsoid to ovoid, colorless, 20–25 × 12.5–17.5 µm. Anamorph unkown. Host range and distribution: On the leaves of Carpinus laxiflora, Asia, Japan. Additional materials examined: Japan, Tochigi Prefecture, Sano-shi, Mikamoyama Park, on Carpinus laxiflora, 19 Mar 2003, leg. H. Masuya, MUMH 3694; 4 Mar 2006, leg. H. Masuya, MUMH 3813; 20 Sep 2006, leg. S. Takamatsu, Of the seven powdery mildew species known to occur on Carpinus, five belong to Erysiphe section Uncinula (Lév.) U. Braun & Shishkoff, which has appendages with uncinatecircinate apex. Erysiphe ellisii belongs to the section Microsphaera (Lév.) U. Braun & Shishkoff, which has appendages with apex dichotomously branched several times. Erysiphe fimbriata, having simple, mycelioid appendages, belongs to the section Erysiphe. Thus, Carpinus is affected by Erysiphe species of all sections known. However, appendages of species of the section Erysiphe usually arise from the lower part of the chasmothecia and are interwoven with hyphae on the surface of the leaves. In contrast, appendages of E. fimbriata arise from the upper part of chasmothecia and turn upward, which is quite different from the appendages of most species of the section Erysiphe, except for some species that are intermediate between the sections Erysiphe and Microsphaera, as, for instance, Erysiphe tortilis (Wallr.) Link: Fr. and E. trifolii Grev., and allied species in which the appendages turn upward (toward one direction). The phylogenetic analysis also supports that E. fimbriata belongs to the lineage of section Uncinula, but not to section Erysiphe. In species of Erysiphe section Uncinula, the appendages mostly arise equatorially, but in Uncinula forestalis Mena, now Caespitotheca forestalis (Mena) S. Takam. & U. Braun, the terminal appendages turn toward one direction. Moreover, the large size of chasmothecia and numerous asci of E. fimbriata demonstrate that this species is a unique fungus among the genus Erysiphe. Phyllactinia guttata (Wallr.: Fr.) Lév., one of the powdery mildews that infect Carpinus, also has large chasmothecia (150–250 µm diameter). This fungus has needle-shaped appendages with a bulbous base, which is quite different from the mycelioid appendages of E. fimbriata. Therefore, E. fimbriata differs from any other powdery mildew species known to occur on Carpinus, and also differs from any other powdery mildew species. We thus propose E. fimbriata as a new species of the Erysiphaceae. Molecular phylogenetic analyses support that E. fimbriata belongs to the genus Erysiphe, which is consistent with the morphological characteristics of this fungus having multi-asci chasmothecia and mycelioid appendages. Molecular analyses also demonstrate that the phylogenetic position of E. fimbriata is ambiguous within Erysiphe, i.e., there is no Erysiphe species closely related to E. fimbriata. Erysiphe species most closely allied to E. fimbriata are E. paeoniae R.Y. Zheng & G.Q. Chen and E. arcuata in 28S rDNA (97.5% similarity). ITS sequence similarities of E. fimbriata are less than 90% to all other Erysiphe species used in this study. Sequence similarity of E. fimbriata to Erysiphe species parasitic on Carpinus are 95.3%–97.5% in the 28S rDNA and 77.4%–87.3% in ITS regions, which indicates that E. fimbriata is distantly related to all other 191 Erysiphe species reported on Carpinus. These data suggest that E. fimbriata is a unique fungus genetically as well as morphologically. Erysiphe fimbriata was first found as chasmothecia attached on twigs of C. laxiflora in litter. Our first assumption was that E. fimbriata colonized the twigs of C. laxiflora and later formed chasmothecia there. To confirm this assumption, we visited the Mikamoyama Park several times from May to December in 2006. However, we failed to observe the fungus colonizing on twigs during this period. Therefore, the chasmothecia might be transferred from leaves to twigs after maturation in some unknown way. The evidence that the chasmothecia are attached to the twigs upside down may support this assumption. The long appendages turning upward from the chasmothecia might have some function in the dispersal process. Erysiphe carpini-laxiflorae also occurs on C. laxiflora in the Mikamoyama Park. Erysiphe carpini-laxiflorae usually occurs on young seedlings of C. laxiflora, but not on the adult tree, whereas E. fimbriata occurs on a large tree, about 15–20 m tall. Thus, the two powdery mildews that occur on C. laxiflora seem to have different ecological niches. However, additional detailed ecological studies of these fungi are required. Acknowledgments We thank Dr. Uwe Braun for critical reading of the manuscript and Dr. Chiharu Nakashima for the Latin description. References Amano K (1986) Host range and geographical distribution of the powdery mildew fungi. Japan Scientific Societies Press, Tokyo Braun U (1987) A monograph of the Erysiphales (powdery mildews). Beih Nova Hedwigia 89:1–700 Braun U (1995) The powdery mildews (Erysiphales) of Europe. 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