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Fruit deformation of Symplocos myrtacea Siebold et Zuccarini (Japanese sapphireberry) caused by Exobasidium species has been reported in Fukuoka Prefecture, Japan but the species involved has not been determined (Ogawa 1999, 2000). Five species and varieties of Exobasidium were recorded on Symplocos species previously (Sydow et al. 1912, Hirata 1981, Ezuka 1991, Nagao et al. 2003). Exobasidium symploci Ell. &Mart. was identified on S. tinctoria (L.) L’Hér. in Alabama, Florida, Indiana, and North Carolina, USA. Two Exobasidium spp. were recorded from Tropical Asia: E. indicum Syd. & Butl. on S. theaefolia D. Don in Darjeeling and E. javanicum Rac. on S. spicata var. subsessilis Koord. & Valeton (syn. S. cochinchinensis subsp. laurina (Retz.) Noot.) in Java. In Japan, the following Exobasidium spp. were described on Symplocos species: E. symploci-japonicae var. symploci-japonicae Kusano & Tokubuchi and E. symploci-japonicae var. caprogenum Nagao & S. Ogawa on S. lucida (syn. S. kuroki Nagam.), and E. sakataniense S. Hirata on S. theophrastaefolia Siebold & Zucc.

In June 2017, deer-horn-like galls covered with a whitish, powdery fungal layer were found on the trunks of Cinnamomum pseudopedunculatum (Lauraceae) in Hahajima, Bonin Islands, Japan. The galls were similar to those of horn gall disease of Ci. tenuifolium caused by Laurobasidium hachijoense (Laurobasidiaceae, Exobasidiales) on Hachijo Island, approximately 700 km north of Hahajima. Based on morphological observation and molecular analyses of ITS and LSU regions, the fungus isolated from the surface of the galls was identified as L. hachijoense. This is the first report of the horn gall disease of Ci. pseudopedunculatum.

A new combination, Clinoconidium inouyei, is proposed to accommodate Uredo inouyei (syn. Ustilago inouyei, Melanopsichium inouyei, Ustilago machili) from Japan, producing galls on shoot buds of Machilus japonica (Lauraceae). This taxonomic treatment is based on observations of gastroid sporulation in peripheral lacunae of the host galls and basidiospore morphology. This is also supported by phylogenetic analyses with LSU and ITS regions of rDNA. This species is morphologically and phylogenetically similar to C. onumae producing galls on shoot buds of Cinnamomum tenuifolium reported from Japan, but has larger basidiospores.

Clinoconidium lauracearum sp. nov. (Cryptobasidiaceae) is described and illustrated from infected fruits of Cinnamomum tamala (Lauraceae) collected from Rudraprayag district of Uttarakhand State, India. The species shows characteristics of Clinoconidium and Drepanoconis, but differs from other species in these genera by the combination of shapes, sizes, and septation of basidiospores. Molecular data also indicate that the present taxon is distinct from the other known species of Clinoconidium and Drepanoconis. Analyses of combined ITS and LSU rDNA and separate LSU rDNA sequence data reveal a close association of the present taxon to the genus Clinoconidium, but also that it is distinct from the other known species in the genus.

The Brachybasidiaceae are a family of 22 known species of plant-parasitic microfungi belonging to Exobasidiales, Basidiomycota. Within this family, species of the largest genus Kordyana develop balls of basidia on top of stomatal openings. Basidial cells originate from fungal stroma filling substomatal chambers. Species of Kordyana typically infect species of Commelinaceae. During fieldwork in the neotropics, fungi morphologically similar to Kordyana spp. were found on Goeppertia spp. (syn. Calathea spp., Marantaceae), namely on G. panamensis in Panama and on G. propinqua in Bolivia. These specimens are proposed as representatives of a genus new to science, Marantokordyana, based on the distinct host family and molecular sequence data of ITS and LSU rDNA regions. The specimens on the two host species represent two species new to science, M. oberwinkleriana on G. panamensis and M. boliviana on G. propinqua. They differ by the size and shape of their basidia, molecular sequence data of ITS and LSU rDNA regions, and host plant species. In the past, the understanding of Brachybasidiaceae at order and family level was significantly improved by investigation realized by Franz Oberwinkler and his collaborators at the University of Tübingen, Germany. On species level, however, our knowledge is still very poor due to incomplete species descriptions of several existing names in literature, scarceness of specimens, as well as sequence data lacking for many taxa and for further barcode regions. Especially species of Kordyana and species of Dicellomyces are in need of revision.

In this study, the complete mitochondrial genome of Meira sp. was sequenced and assembled. The complete mitochondrial genome of Meira sp. has 15 protein-coding (PCG) genes, 2 ribosomal RNA (rRNA) genes, and 22 transfer RNA (tRNA) genes. The mitochondrial genome of Meira sp. has a total size of 23,353 bp, with the base composition as follows: A (30.62%), T (32.82%), G (17.84%) and C (18.73%). Phylogenetic analysis indicated that the mitogenome of Meira sp. exhibited a close relationship with the mitogenome of Jaminaea angkorensis.

International audience; The systematic position of three yeast strains isolated from a plant cell culture, a piece of termite nest, or as a foliar endophyte of Coffea arabica, respectively, is evaluated using morphological, physiological, and phylogenetical characteristics. In culture, all three isolates produced white, pale orange to pink colored colonies of cylindrical cells with monopolar budding and pseudohyphae. Standard phenotypic, biochemical, physiological characterization, and phylogenetic analyses of the combined 26S rRNA gene (D1/D2 domains) and ITS region sequences showed the conspecificity of these isolates and suggest their placement within the Exobasidiales (Ustilaginomycotina) as a sister lineage of the sampled and sequenced Graphiola species. Here, we describe this species as Graphiola fimbriata sp. nov. MycoBank MB 825077 (holotype: PC1T; ex-type cultures: IBRC-M 30158T = CBS 13945T = DSM 104832T). This is the first species described in the genus Graphiola for which only the asexual, saprobic developmental phase is known. The description of the genus Graphiola is therefore emended to allow species known only from a saprobic state.

The order Ceraceosorales (Ustilaginomycotina) currently includes the single genus Ceraceosorus, with one species, Ceraceosorus bombacis, parasitic on Bombax ceiba in India. The diversity, biogeography, evolution, and phylogenetic relationships of this order are still relatively unknown. Here, a second species of Ceraceosorus is described from West Africa as a novel species, Ceraceosorus africanus, infecting Bombax costatum in Benin, Ghana, and Togo. This species produces conspicuous fructifications, similar to corticioid basidiomata when mature, but sorus-like in early stages of ontogenetic development. The fructifications cover much of the leaf surface and resemble leaf blight. This contrasts with the inconspicuous fructifications of C. bombacis comprising small spots scattered over the lower leaf surface that resemble leaf spot. Both species of Ceraceosorus differ in several micromorphological traits, infect different host plant species in widely separated geographical areas, and are separated by a considerable genetic distance in 28S rDNA and RPB2 genes. The distinct corticioid fructification of C. africanus is a unique morphological trait within the Ustilaginomycotina. Molecular phylogenetic analyses of a single gene dataset (D1/D2 28S rDNA) supported the monophyly of the two Ceraceosorus species and the Ceraceosorales and their placement within the Ustilaginomycotina. Molecular phylogenetic analyses of a multigene dataset (18S/5.8S/28S rDNA/RPB2/TEF1) revealed Exobasidium rhododendri (Exobasidiales) as the closest relative of Ceraceosorus, both clustering together with Entyloma calendulae (Entylomatales), indicating affinities to the Exobasidiomycetes. This phylogenetic placement is in agreement with ultrastructural characteristics (presence of local interaction zone and interaction apparatus) reported for the Ceraceosorales, Entylomatales, and Exobasidiales.

Graphiola phoenicis was found on leaves of Phoenix canariensis in Hanga Roa, Easter Island, Chile. Amphigenous black pulvinate basidiomata were abundant on the leaf blades and rachides, causing extensive foliar damage. The samples were examined by a light microscope after three days in a humid chamber. In addition, the molecular tools scanning electron microscopy and histological sectioning were used to study the fungal/host relationship, complementing the identification. Morphometric and molecular characteristics led to the identification of the fungus as Graphiola phoenicis causing false smut on the Canary date palms (Phoenix canariensis). This is the first report of this plant pathogen in Chilean territory. Resumen En hojas de Phoenix canarienis en Hanga Roa, Isla de Pascua, Chile, se encontró abundantes basidiomas pulvinados, negros, amfígenos negros sobre las pinnas y en el raquis de las hojas, causando daño foliar extensivo. Después de tres días en cámara húmeda se examinaron muestras con microscopio compuesto. Además, para estudiar la relación hongo/hospedero, se utilizó microscopía electrónica de barrido y cortes histológicos, complementariamente se aplicaron herramientas moleculares en la identificación. Las características morfométricas y moleculares permitieron la identificación del hongo como Graphiola phoenicis, agente causal del falso carbon en Palma de Canarias (Phoenix canariensis) en Isla de Pascua, Chile. Este es el primer reporte de este fitopatógeno en territorio chileno.

Graphiola phoenicis was found on leaves of Phoenix canariensis in Hanga Roa, Easter Island, Chile. Amphigenous black pulvinate basidiomata were abundant on the leaf blades and rachides, causing extensive foliar damage. The samples were examined by a light microscope after three days in a humid chamber. In addition, the molecular tools scanning electron microscopy and histological sectioning were used to study the fungal/host relationship, complementing the identification. Morphometric and molecular characteristics led to the identification of the fungus as Graphiola phoenicis causing false smut on the Canary date palms (Phoenix canariensis). This is the first report of this plant pathogen in Chilean territory.

The taxonomy of fungi from the orders Tremellales, Auriculariales. Septobasidiales and related groups (Tulasnellales, Dacrymycetales, Exobasidiales, Sporobolomycetaceae) and the taxonomic position of these fungi within class Basidiomycetes is discussed. The author also presents ideas on the origin, evolution and age of tremellaceous fungi.

The genus Meira currently contains three recently described species of mite-associated basidiomycete yeasts from Israel and Japan and is placed in the Exobasidiomycetes (Ustilaginomycotina) Incertae sedis. A previously undescribed species of Meira was isolated from the phylloplane of a magnolia leaf in Louisiana, USA. Herein, we describe Meira miltonrushii sp. nov. and include phylogenetic analyses from three rDNA loci to resolve the placement of Meira. This study provides evidence that Meira belongs to the family Brachybasidiaceae in the Exobasidiales and supports the placement of another mite-associated yeast genus, Acaromyces, within Cryptobasidiaceae (Exobasidiales). We also examine sequences produced by numerous environmental studies that suggest Meira species can be found as endophytes of many plant species. To our knowledge, this is the first record of a member of the genus Meira in North America.

Exobasidium ferrugineae, associated with hypertrophied flowers and less commonly leaves of Lyonia ferruginea (rusty staggerbush), is formally described here as a new species. Morphological and DNA sequence (ITS, nLSU) data are provided. Phylogenetic analyses confirm that it is not conspecific with any species of Exobasidium represented by existing DNA sequence data. A key to North American species of Exobasidium on Lyonia is presented.

A fungal disease with aerial-root-liked gall symptoms on Cinnamomum subavenium in Khao Yai National Park, Northeastern Thailand is reported, and the causative agent identified as Laurobasidium hachijoense . Cultures from the Thai specimens, as well as the type culture from Japan, were sequenced for LSU and ITS genes. Analysis of these gene sequences showed that the Thai isolates clustered with the type strain of Laurobasidium hachijoense . This is the first report of this fungus on a new host and in Thailand. Morphology of this fungus from the Thai specimens as well as the seasonal symptom in the natural forest are described and illustrated. Laurobasidiaceae is proposed as a new family for Laurobasidium . It was nested in a highly supported clade with the Cryptobasidiaceae and a sister clade to the Branchybasidiaceae, Graphoilaceae and Exobasidiaceae clades within the order Exobasidiales. Laurobasidiaceae morphologically possesses basidial sterigmata, thin-walled basidiospores with an abaxial hilum, and sporulating on the surface of the host tissues. It is unique from other families in the Exobasidiales in causing aerial-root-like galls on the host plant. The phylogenetic analysis revealed that strains of Acaromyces ingoldii grouped together with Laurobasidium hachijoense indicating they are conspecific. Morphological examination also confirmed that these two taxa are the same fungus. Laurobasidium hachijoense is proposed as the valid name based on its occupation of the initial type material of this organism, and the monotypic genus Acaromyces becomes a synonym of Laurobasidium . Exobasidium cinnamomi is also considered a Laurobasidium species based on its morphology and the stag-horn-like galls on a lauraceous host. The taxonomy of the Laurobasidiaceae is discussed.

To gain insight in the phylogenetic relationships within the Exobasidiales, septal pore apparatus, host-parasite interactions, sori, hymenia, basidia, and nucleotide sequences from the 5′ terminal domain of the nuclear large subunit rRNA gene were studied and compared.

A new combination, Clinoconidium onumae, is proposed to accommodate Ustilago onumae (syn. Melanopsichium onumae) from Japan, producing galls on shoot buds of Cinnamomum tenuifolium (Lauraceae). This taxonomic treatment is based on observations of gastroid sporulation in peripheral lacunae of the host galls and basidiospore morphology. This species is morphologically and phylogenetically similar to Cl. cinnamomi producing galls on fruits of Ci. burmannii, reported from Taiwan, but differs by having larger basidiospores and different morphology of the gall structures, and by affecting different plant organs.

A new name, Clinoconidium globosum, is proposed to accommodate Sphacelotheca cinnamomi from Japan, producing galls on fruits of Cinnamomum daphnoides (Lauraceae). This decision is based on observations of gastroid sporulation in peripheral lacunae of the host galls and basidiospore morphology. This species is characterized by small, globose basidiospores. Its morphological features are described based on newly collected specimens. Results of recently published phylogenetic analyses also support this new name.

Characteristics of hyphal septation, cellular interaction, sporulation, cultures and/or nucleotide sequences from the 5’ terminal domain of the nuclear large subunit rRNA gene of some species of Exobasidium, Microstroma and Muribasidiospora were examined and compared. Our analyses show that the order Microstromatales comprises Microstroma, Muribasidiospora triumfetticola and the anamorphic species Rhodotorula bacarum, R. phylloplana and Sympodiomycopsis paphiopedili , whereas Muribasidiospora hesperidium and Muribasidiospora indica are members of the Exobasidiales. Because of the high degree of morphological divergence between Muribasidiospora triumfetticola and Microstroma , a new genus, Volvocisporium , and a new family, Volvocisporiaceae , of the Microstromatales are proposed. Apart from the phylogenetic implications, the most interesting observations in the present work are the unusual development of the basidia, especially of the basidiospores, and the nutrient transport system from the host attacking hyphae to the basidia in Muribasidiospora triumfetticola.

Summary Fourteen species of Exobasidiales are reported from Scotland with notes on their ecology, distribution and the effects on their hosts, which are mostly members of the Ericaceae.

Microcycle conidiation is defined as the germination of spores by the direct formation of conidia without the intervention of mycelial growth, as occurs in most normal life cycles. It is a method of asexual spore formation in which the normal life cycle of the fungus is bypassed. Spores formed through sexual reproduction and species with unicellular thalli are not included in microcycle conidiation. The term secondary conidium or secondary spore is usually, but not always, synonymous with microcycle conidiation. In the laboratory various factors, but especially temperature, can induce the microcycle condition in such fungi asAspergillus niger, Penicillium andNeurospora crassa, providing a useful tool for research. Microcycle conidiation has also been reported in a broad range of species in nature, and comprises a normal part of the life cycle in several groups, including the Entomophthorales, Taphrinales, Clavicipitales, Uredinales, Ustilaginales, Tremellales and Exobasidiales. The presence of a microcycle in such fungi undoubtedly provides a survival mechanisn for spores that encounter unfavorable conditions.

Publisher Summary This chapter focuses on the teleomorphic and anamorphic genera of heterobasidiomycetous yeasts. The anamorphic basidiomycetous yeasts are currently assigned to two families: Cryptococcaceae and Sporobolomycetaceae. Cryptococcaceae is restricted to anamorphic heterobasidiomycetous yeasts and yeastlike fungi. The genera of this family are Cryptococcus, Bullera, Fellomyces, Kockovaella, Phaffia, Trichosporon, Tschuchiyaea, Udeniomyces, and perhaps Hyalodendron and Moniliella. Sporobolomycetaceae is restricted to anamorphic yeasts and yeastlike fungi. The type genus of this family is Sporobolomyces. Other genera include Bensingtonia, Kurtzmanomyces, Sterigmatomyces, and Rhodotorula. The Heterobasidiomycetes with yeasts and yeastlike-states are distinguished by basidial morphology, septal pore anatomy, and cell wall composition.The telemorphic genera of heterobasidiomycetous yeasts include various orders including, Sporidiales, Ustilaginales, Tilletiales, Graphiolales, Exobasidiales, and Cryptobasidiales. The exobasidiales are plant parasites, which are found in various plant species. The dikaryotic mycelium grows internally in the host (mostly on leaves of Vacciniaceae in exobasidium), transforming leaves into hypertrophied, inflated, bladdery structures suggestive of fruits. Graphiolales contains a small number of poorly-known species of which only the widely spread Graphiola phoenicis has been studied in detail. The fungus produces minute blister-like sori on palm leaves. Catenate globose cells within the sorus are simple basidia. Meiosis occurs in these cells, and haploid basidiospores bud directly from the basidia to yield yeast colonies.

In the course of molecular characterization of yeasts isolated from decaying leaves collected in Cambodia, anamorphic yeast strains were detected that clustered with the Microstromatales in molecular phylogenetic analyses of the chromosomal regions coding for the D1/D2 domain of the large-subunit 26S rRNA gene, the small-subunit 18S rRNA gene and the internal transcribed spacer ITS1-5.8S rRNA gene-ITS2. In the trees obtained, the isolates formed a distinct, basal branch of Microstromatales supported with high bootstrap values. As the isolates could not be identified with any known genus, we have described them as Jaminaea angkorensis gen. et sp. nov. (type strain C5b(T)=CBS 10918(T)=CCY 88-1-1(T)). In the chromosomal region coding for the 18S rRNA gene, the type strain of the novel species contained a group IB intron that was similar in location and sequence to introns found in certain species of Exobasidiales and Entylomatales. As no similar introns have been detected in Microstromatales, the new genus might represent a phylogenetic link connecting these three orders.

This study records a severe outbreak of a disease on Zizyphus mucronata (Rhamnaceae) in Greater Kruger National Park, South Africa. The causal agent of the disease was found to be Coniodictyum chevalieri, a fungus previously believed to be very rare. Detailed illustrations of the symptoms and fungus are presented in order to facilitate future studies. The known geographical distribution of Coniodictyum is presented in relation to the distribution of its host, and a short review of its systematic history is also given. This also treats an invalidly published species name in South Africa, which has confused the literature. A DNA-based phylogeny is presented for the pathogen and this reflects the unique nature of its geographical distribution and biology.

The genus Quambalaria consists of plant-pathogenic fungi causing disease on leaves and shoots of species of Eucalyptus and its close relative, Corymbia. The phylogenetic relationship of Quambalaria spp., previously classified in genera such as Sporothrix and Ramularia, has never been addressed. It has, however, been suggested that they belong to the basidiomycete orders Exobasidiales or Ustilaginales. The aim of this study was thus to consider the ordinal relationships of Q. eucalypti and Q. pitereka using ribosomal LSU sequences. Sequence data from the ITS nrDNA were used to determine the phylogenetic relationship of the two Quambalaria species together with Fugomyces (= Cerinosterus) cyanescens. In addition to sequence data, the ultrastructure of the septal pores of the species in question was compared. From the LSU sequence data it was concluded that Quambalaria spp. and F. cyanescens form a monophyletic clade in the Microstromatales, an order of the Ustilaginomycetes. Sequences from the ITS region confirmed that Q. pitereka and Q. eucalypti are distinct species. The ex-type isolate of F. cyanescens, together with another isolate from Eucalyptus in Australia, constitute a third species of Quambalaria, Q. cyanescens (de Hoog & G.A. de Vries) Z.W. de Beer, Begerow & R. Bauer comb. nov. Transmission electron-microscopic studies of the septal pores confirm that all three Quambalaria spp. have dolipores with swollen lips, which differ from other members of the Microstromatales (i.e. the Microstromataceae and Volvocisporiaceae) that have simple pores with more or less rounded pore lips. Based on their unique ultrastructural features and the monophyly of the three Quambalaria spp. in the Microstromatales, a new family, Quambalariaceae Z.W. de Beer, Begerow & R. Bauer fam. nov., is described.Taxonomic novelties: Quambalariaceae Z.W. de Beer, Begerow& R. Bauer fam. nov., Quambalaria cyanescens (de Hoog & G.A. de Vries) Z.W. de Beer, Begerow & R. Bauer comb. nov.

Austrobasidium pehueldeni gen. & sp. nov. is described on Hydrangea serratifolia (H. et A.) F. Phil. from Chile. This study adds to the very few reports of Exobasidiales causing formation of stem galls and presents the first species known to parasitise a woody epiphyte and member of Hydrangeaceae (Cornales). A. pehueldeni is compared to the morphologically very similar Laurobasidium lauri (Geyler) Jülich and the systematic position of both species is discussed.

Date palm (Phoenix dactylifera) is the most important fruit tree in the state of Qatar and is widely planted in rural areas. In urban areas it is a common ornamental and shade plant, grown in parks and gardens and alongside roads. During spring and summer of 2001 and 2002, several date palm trees located in Al Ka'ban area (northern Qatar) showed symptoms typical of false smut disease. The fungus results in subepidermal spots on both sides of the pinnae (leaflets) and on the rachis, with small, black sori developing in abundance on old fronds. Once the spores have disseminated, only the rough black craters of the sori remain. More severe infections and damage were observed in areas of higher humidity, especially in Al Mashrub, located in the northeast coastal strip. Severe infection reduces tree growth and date production through premature death of leaves. The sori were 1-3 mm in diameter, occurred on both sides of the pinnae and were typically more abundant in the apical regions. These superficially resembled a scale insect or mealy bug infestation, but closer examination revealed the exudation of powdery yellow spores on whitish filaments. Spores were spherical to ellipsoidal, 3-6 μm in diameter and had a thick, smooth hyaline wall. The fungus was identified as Graphiola phoenicis (Djerbi, 1983), commonly known as false smut disease. It is also known as graphiola leaf spot and palm leaf pustule. Disease attacks were most common on 7- to 10-year-old palm trees and most evident on the older fronds. The disease has now spread to date palm groves throughout the country, but more quickly where trees are planted at higher densities (4-5 m spacing). False smut disease is now affecting individual date palm trees in the north, central and south areas of Qatar. False smut disease has previously been recorded on P. dactylifera in India, Egypt and Brazil (CAB International, 2003), Libya (Edongali, 1996) and Kenya (Kung'u & Boa, 1997). This is the first report of Graphiola phoenicis occurring on date palm trees in Qatar.

In the spring of 2001, diseased trees of Juglans regia in Hatay, in the Mediterranean region of Turkey, showed typical symptoms of downy leaf spot, especially following moist and cool conditions. A survey was conducted in the affected regions, which included 12 orchards in Antakya and five orchards in Altinozu districts. Disease prevalences (percentage of fields with plants showing foliar symptoms) in these locations was 83 and 60%, respectively. Disease incidence (percentage of plants with foliar symptoms) ranged from 69 to 87% (of between 15 and 36 samples per location). Initially, disease symptoms were characterized by a whitish efflorescence containing fungal structures and spores on the lower surface of the affected leaf, often concentrated along the veins, and a yellowish discoloration on the corresponding upper surface of the leaf. In the later stages of disease development, as the leaf spots enlarged, diseased tissues became necrotic. Sometimes the leaves of infected walnut trees were abnormal and trees became defoliated. Examination of leaf infections using scanning electron microscopy revealed that whitish polygonal efflorescences were basidial structures forming oval basidiospores (6·2–7·8 × 2·9–3·4 μ m). The fungus was identified as Microstroma juglandis , a member of the Exobasidiales, based on morphological and cultural characteristics of the basidium and basidial structures. Isolations on potato dextrose agar using small pieces of surface-sterilized leaf tissue yielded white or creamcoloured, mucoid and yeast-like colonies (Garcia-Jimenez et al ., 1995). Colonies consisted of ellipsoidal to ovoid or clavate cells that reproduced by unipolar budding (von Arx et al ., 1982). Pathogenicity tests were performed on leaves of walnut seedlings by spraying with a spore suspension (approximately 1 × 10 7 conidia mL − 1 ) and covering the plants with polyethylene bags for 3 days at 25 ± 2 ° C and 75–80% relative humidity. Control plants were treated with sterile distilled water. Symptoms identical to those observed in walnut orchards became visible 21–24 days after inoculation. However, lesion development was mild because of the excessively warm conditions (30 ± 2 ° C). In eastern Spain, downy leaf spot on walnuts was previously reported from the province of Valencia (GarciaJimenez et al ., 1995). This is the first report of downy leaf spot on walnuts caused by Microstroma juglandis from Turkey. The disease is generally not considered economically important. However, the impact of downy leaf spot in the eastern Mediterranean region of Turkey in 2001 was significant and caused serious concern to walnut growers. The survey indicates that downy leaf spot may be emerging as a new problem for the walnut growers in Hatay and other areas of Turkey.

Muribasidiospora indica was identified as the causal organism associated with leaf spots of Rhus lancea in South Africa. The disease appears more commonly in the warmer provinces of South Africa (Gauteng, Free State) than in the Western Cape. The morphological identification of the causal organism was confirmed by comparing sequence data of the large subunit rRNA gene (28S) with that of reference strains of M indica. This is the first confirmed record of this species occurring in Africa, where it appears to be a serious leaf pathogen on members of the Anacardiaceae.

The 150 years old classificatory system for smut fungi was recently replaced by a new one, based on ultrastructural and molecular studies and also on classical morphological characters. The c. 1450 known ‘classical’ smut fungi (those possessing ustilospores) are classified into two classes, eight orders, 18 families and 73 genera. The surprising result in this new system is that the Microbotryales, with 93 species in eight genera, are more closely related to the rust fungi than to the remaining group of smut fungi. This is supported by biochemical, ultrastructural and molecular data. In the new system, some groups of fungi are lacking ustilospores (Microstromatales, Exobasidiales). Through convergent evolution, similar, complex spore ball structures, composed of spores and empty sterile cells, evolved from different ancestors as adaptation to parasitism on water plants (Doassansiopsiaceae and Doassansiaceae). The presence (or absence) of spore balls does not always reflect a close relationship as was previously thought: in the Doassansiaceae, characterised so far mainly by spore balls, Doassinga has single spores. Examples of Australasian taxa and their place in the new classification, presented are Doassansiopsis, Doassingaand Pseudotracya of the ‘Doassansia’ group, Mundkurella, Heterotolyposporium, Websdanea, Restiosporium and within the Microbotryales Microbotryum (Microbotryaceae), Fulvisporium and Bauerago (Ustilentylomataceae).

Evidence is presented to show that the fungus, originally described as a species of Cercosporella (Hyphomycetes), introduced into Hawaii to control the composite weed Ageratina riparia, belongs to the white smuts (Ustilaginales). It is formally described as Entyloma ageratinae sp. nov. In addition to two external spore types (sporidia), which occur in prominent hypophyllous caespituli, hyaline, thin-walled, non-resting ustilospores are formed within non-necrotic leaf tissue. A further spore type, the spermatium, is abundantly produced from well-defined spermogonia. The significance of these previously unreported structures in the smut life-cycle is discussed. Entyloma ageratinae was found to be present in the purported centre of origin of its weed host, the Jalapa (Vera Cruz) region of Mexico. Further collections of white smuts on other composite weeds (Parthenium hysterophorus, Melampodium divaricatum) in this locality are assigned to E. compositarum and compared with E. ageratinae. The additional discovery of Kordyana cubensis (Exobasidiales) on Commelina diffusa with a similar spermogonial state is reported and discussed in relation to the evolution of the Ustilaginales and Exobasidiales.

The relationship of Exobasidium (Exobasidiales) to other groups of Basidiomycetes has long been questioned. Although this genus has been traditionally placed in the Holobasidiomycetes, septal ultrastructure, combined with other features of the basidium, suggest a much closer relationship to the Teliomycetes.

TEM studies show that species of Taphrina and Protomyces have cell walls with a thick, electron-transparent inner layer, similar to those of the Endomycetales, e.g., of species of Saccharomyces or Hanseniaspora. The budding is holoblastic at the attenuated end or ends of the cell and is rather similar to that of the apiculate yeasts. Members of the genera Microstroma and Exobasidium have an electron opaque, often multilayered cell wall and show enteroblastic budding, similar to that of the "red yeasts" (Sporobolomycetales) and Ustilaginales. The Taphrinales are consequently classified in the Endomycetes (Ascomycotina), while Microstroma and Exobasidium are placed in the Basidiomycetes. Species of the genera Kabatiella and Aureobasidium have ascomycete-like cell walls, and are therefore not related to Microstroma. The classes of the Ascomycotina and Basidiomycotina are discussed briefly. The Taphrinales are usually considered to be primitive Ascomycetes and have, as a rule, been classified in the Endomycetes (=Hemiascomycetes), which mainly comprise the ascus-forming yeasts. Some authors, however, have suggested that the Taphrinales are related to the Basidiomycetes, particularly to the Sporobolomycetales, Exobasidiales, and Uredinales. As early as 1884, Sadebeck observed that the asci of Taphrina species may form exogenous, stalked budding cells resembling basidiospores. Lohwag (1934) considered the ascus of Taphrina to be a degenerate basidium. Graafland (1960) compared Taphrina to Exobasidium, drawing particular attention to their biological similarity. Both genera contain plant parasites causing hyperplasia, chlorosis, galls or witches' broom, mainly on broad-leaved trees and shrubs. All species of both genera have a parasitic and a saprophytic state. In the parasitic state intercellular hyphal structures are formed which perforate the cuticle or emerge through the stomata giving rise to superficial hymenia of asci or basidia (FIGS. 1, 2). The saprophytic state is yeast-like and propagates by budding. Only young, growing structures of the host plant such as sprouting buds and germinating seeds are susceptible to infection. The species of the genus Microstroma Niessl have a yeast-like, saprophytic and a mycelial parasitic state. The genus had been classified in the Hyphomycetes until Blanz (1978) and Oberwinkler (1978) recognized its basidiomycetous affinity. Microstroma has often been connected with Kabatiella Bubak and Aureobasidi