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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.

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.

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.

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.

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.

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).

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.