Puccinia menthae is highly variable, with several varieties and variants within varieties. Two principal groups of races, nominated spearmint rust and peppermint rust, have been recognized according to their host range on commercially-important Mentha species, yet both belong to the same variety, P. menthae var. menthae. Ten collections of P. menthae teliospores from four Mentha species in Victoria, Australia, were examined using light microscopy and SEM. The teliospores from M. spicata, M.×cordifolia and M. suaveolens, all hosts to spearmint rust, were verrucose with two equally-sized cells, whereas those from M.×piperita, host to peppermint rust, were generally smooth-walled, and the apical cell was larger and thicker-walled than the basal cell. Fifteen isolates of P. menthae collected from four Mentha species in Victoria were assessed for genomic variation using RAPD analysis and PCR-generated length polymorphism of the ITS region of rDNA. Six out of 113 RAPD primers amplified reproducible marker profiles, 58 polymorphic bands were scored and simple matching distances were computed between the isolates. UPGMA cluster analysis was used to produce a dendrogram and non-metric multi-dimensional scaling to produce a two-dimensional map of the isolates. The spearmint rust and peppermint rust isolates clustered into two non-overlapping groups, providing good evidence that there is limited gene flow between them. All isolates had the same sized ITS fragments. The taxonomic implications of these results are discussed and it is suggested that the peppermint and spearmint rusts should be accorded separate varietal or specific status.

The name Agaricus subfloccosus (J. E. Lange) Pilát, based originally on Danish specimens, has been applied to mushrooms growing in coastal northwestern Europe as well as to mushrooms associated with Picea (and Abies) at higher elevations in western Europe. Corresponding populations are also found in these two habitat zones in western North America. Material of both lowland and highland forms from Europe and North America was studied using morphological, cultural, and genotypic approaches. Homothallism was consistently observed in those isolates studied. Individual and population level genetic data are also consistent with homothallic reproduction. Dissimilarity analysis of multilocus nuclear and mitochondrial genotypes based on allozyme and DNA RFLP markers provided strong evidence that, within either ecologically distinct group, the amphiatlantic populations were genotypically very similar. Conversely, there were large genotypic differences between the two ecologically distinct groups, whether within or between continents. Supported by cultural and morphological evidence, these data indicate that two ancient, phylogenetically distinct entities exist within current concepts of A. subfloccosus. A formal taxonomic resolution is complicated by the lack of a holotype for Lange's species.

Four strains of Tuber borchii were grown in liquid medium containing glucose. Evaluation of growth patterns revealed a trend of exponential growth for only one strain. Subsequently, enzyme levels were assayed and polypeptide and mRNA electrophoretic profiles were analyzed. Although the four strains were found to have many properties in common such as the growth behaviours for three strains and the levels of some glycolytic enzymes, the polypeptide and mRNA electrophoretic patterns highlighted intraspecific variability.

The ability of the maize pathogen Fusarium subglutinans to metabolize benzoxazolin-2(3H)-one (BOA) and 6-methoxybenzoxazolin- 2(3H)-one (MBOA), important allelochemicals of Zea mays, was studied. Growth of mycelium was completely inhibited by 10 mM BOA and reduced by lower concentrations. In vitro the fungus completely degraded 1 mM concentrations of BOA and MBOA within 2 d. N-(2-hydroxyphenyl)-malonamic acid and N-(2-hydroxy-4-methoxyphenyl)-malonamic acid were identified as the main degradation products of these allelochemicals.

The avidity of conidia and 48-h-old germlings of Coniothyrium minitans for FITC-conjugated lectins was characterised by flow cytometry and digital microscopy. Six isolates of C. minitans representing three morphological types were compared. Binding of Con A, SBA and WGA by conidial populations varied markedly in extent and pattern between isolates, however, with increasing culture age, conidia from all isolates demonstrated a significant reduction in lectin avidity. Germling isolates bound significantly different amounts of lectins and lectin binding differed significantly with locality. Spore walls of all germlings from all isolates bound more Con A compared with hyphal apices and mature hyphal walls. In contrast, hyphal apices of the majority of germling isolates, readily bound SBA and mature hyphal walls of germling isolates bound more WGA than other regions of the germlings. Such differential lectin binding by conidia and germlings may influence their specific surface interactions and adherence characteristics.

The thn (thin) mutant strain of Schizophyllum commune, which normally lacks aerial mycelium, produced excessive aerial hyphae when surrounded by multiple wild-type (wt) colonies. When thn and wt mycelia were grown together, the radial growth rate of the thn strain was increased, whereas the wt strain was clearly expressed in its growth, resulting in complete overgrowth of wt by thn hyphae. Overgrowing even occurred when mixtures of fragmented hyphae of both strains with a hundred times excess of wt hyphae over thn hyphae were grown from a single inoculum. Growth stimulation was also observed when thn and wt colonies were separated by dialysis membrane (cut-off 6–8 kDa) suggesting that low molecular weight molecules may be involved. The observed phenomena may explain the apparently very high frequency of occurrence of the recessive thn mutation in S. commune.

Plating of individual soil particles onto an agar medium, poured into Petri dishes, is a method of studying fungal distribution between microhabitats in soil. The substitution of Petri dishes with well plates reduced both the required amount of agar medium and labour. A microshovel prepared from an injection needle facilitated the handling of individual, small size, soil particles (0·25–0·50 mm). The described method was evaluated in a study of the distribution of Fusarium within two wheat field soils from Ås, Norway, and from Østermarie, Denmark. Four types of organic particles were distinguished: light coloured root pieces, dark coloured root pieces, straw pieces, and miscellaneous organic pieces. The dominating species were F. culmorum, F. oxysporum and F. avenaceum. Aspects on the value of the method with regard to fungal substrate preference are discussed.

Progress in understanding the biology of arbuscular mycorrhizal fungi is hampered by the limited number of species that can be successfully propagated and studied in vitro. We report the establishment of monoxenic cultures of Glomus etunicatum in association with excised Ri T-DNA transformed carrot roots. The fungus can be propagated in vitro using monoxenically formed resting spores and/or colonized root fragments. Modified White's medium buffered with 10 mM MES (pH 6) or MOPSO (pH 6·5) was most optimal for the host root growth as well as for G. etunicatum spore germination and mycorrhiza formation. The number of resting spores formed in vitro correlated positively with the length of roots occupied by arbuscular mycorrhizal structures, including arbuscules and vesicles. Spores first appeared in dual cultures within two weeks of root inoculation. Sporulation was asynchronous and continued until root senescence. Under applied culture conditions, spores achieved mature appearance within 5–7 d after their initiation. Approximately 6% of monoxenic spores were aborted at different stages of their development. Although G. etunicatum spores formed in vitro exhibited general morphological and anatomical similarity to soil-borne inoculum, they were significantly smaller and had thicker spore walls than their soil-borne counterparts. Caution should, therefore, be exercised in utilizing the in vitro system as a model of growth and development of glomalean fungi in soil.

The cultivated mushroom Agaricus bisporus was grown and fruited in wheat straw compost. RNA was extracted from samples of mycelium growing in compost during colonization and fruit body development. Laccase gene (combined lcc1 and lcc2) expression and cel3 gene (cellobiohydrolase) expression were determined by Northern blot analysis and by competitive RT-PCR. The level of laccase transcripts was highest in colonized compost (prior to the onset of fruiting), declined during the period of fruit body enlargement and increased again after harvesting and during the second flush of fruit body production. No transcripts of the cel3 gene were detectable in colonized or pre-fruiting cultures, but the level became detectable and rose to a maximum at the veil-break stage of fruiting, declined after harvesting and rose again during the second flush. Gene expression for laccase and cellobiohydrolase correlated with the known changes of laccase and cellulase enzyme activities during the fruiting life cycle.

Nine ascomycetes, 1 basidiomycete and 15 mitosporic fungi are reported from submerged wood, collected from a single English river site. Ascotaiwania pallida, Neta angliae and Trichocladium englandense spp. nov. and Frigidispora colnensis gen. & sp. nov. are described and illustrated. Most of the species present on the submerged wood appear to have been identified, for the single date and location sampled, because the asymptote of the accumulative curve was reached between 80–100 substrata. The results of this study are compared with those from collections, using similar collection techniques in tropical regions. Results suggest that temperate streams appear to have a lower fungal diversity than in the tropics. Only Acrogenospora sphaerocephala was common to tropical (Seychelles) and temperate (U.K., River Coln) sites.

Massarina proprietunicata sp. nov., is described and illustrated based on a specimen occurring on submerged wood in the Lam Tsuen River, Hong Kong. It is characterized by verrucose ornamented ascospores bearing a narrow mucilaginous sheath, which is drawn out at the poles to form tapering appendages, with thickened and arrowhead-like tips. Massarina proprietunicata is compared with other aquatic Massarina species having ascospores bearing a narrow mucilaginous sheath or polar appendages. Details of morphology are illustrated with interference and scanning electron micrographs.

The ability of three Australian Pisolithus species, discriminated on the basis of ITS sequence data, to utilize a range of inorganic and organic nitrogen sources was assessed in liquid axenic culture. Both intra-, and putative interspecific, variation in nitrogen source utilization was observed. Most isolates demonstrated a preference for NH4+ over NO3−, although some showed no significant preference for either inorganic source. All isolates utilized a range of amino acids. Species I isolates demonstrated a preference for acidic and/or neutral amino acids over basic acids, while species II and III isolates generally utilized amino acids poorly relative to species I. Although most isolates utilized BSA poorly, two species I isolates that had been maintained in axenic culture for > 10 y grew well on this substrate, suggesting possible changes in nitrogen utilization with extended storage in axenic culture.

The vascular wilt pathogen currently causing severe die-back and mortality of takamaka in the Seychelles has morphological and physiological characters inconsistent with its placement in Verticillium. Features of the pathogen warrant its transfer to Leptographium and Leptographium calophylli comb. nov. is proposed. L. calophylli is described in detail based on new collections.

Analysis of Amplified Fragment Length Polymorphisms (AFLP) in a sample population of Epichloë and Neotyphodium was conducted to evaluate the usefulness of this technique in estimating phylogenetic relationships among these fungi. A total of 963 unique restriction fragments were identified with 13 selective primer combinations. Neighbour-joining and parsimony analysis produced phylogenetic trees with high bootstrap support. All Epichloë festucae isolates were monophyletic, and clades of E. festucae were identified that correspond to the host species from which they were isolated. These groups may indicate the importance of coevolution in the development of the fine fescue-E. festucae symbiosis. The grouping of E. festucae isolates from hard fescue and Chewings fescue into one clade conflicts with the current taxonomy of these host grasses. Sequencing of ribosomal DNA spacer regions ITS1 and ITS2 was conducted for comparisons to the phylogenetic relationships estimated by AFLP. Using the maximum likelihood test, a significant difference was detected between AFLP and rDNA trees due to discrepancies in the association of anamorphs (Neotyphodium) and teleomorphs (Epichloë). This discrepancy may be due to some mechanism of genetic recombination, such as hybridization or parasexual recombination, that occurs in Neotyphodium populations. It is concluded that AFLP markers are useful for producing meaningful phylogenies among a diverse group of fungi and for identifying groups of closely related individuals that are genetically and biologically similar. Further investigation is needed to determine how AFLP markers change over short periods of time in populations and over evolutionary time.

Two new species of Wawelia are described from rabbit and hare dung incubated under conditions of restricted water supply. A key to the five known species of Wawelia is provided.

Mating type and RG57 fingerprints were determined for 141 isolates of Phytophthora infestans from 63 fields in all the important potato growing areas in Norway and Finland. Seventy-six multilocus genotypes were identified, of which 53 were detected only once. Norwegian and Finnish isolates were similar in terms of genotypic diversity and the genetic distances between the genotypes. The large number of genotypes and the high genetic distances between the genotypes indicate that sexual reproduction is contributing significantly to the genetic variation of P. infestans in Norway and Finland.

Five ophiostomatoid taxa have been found associated with the infructescences of Protea species, an ancient group of flowering plants endemic to South Africa. Two of these fungi are characterized by their unusual Knoxdavesia anamorphs and have been placed in Gondwanamyces. The three remaining species have Sporothrix anamorphs and have accordingly been accommodated in Ophiostoma. The phylogenetic relationships between the fungi associated with Protea spp. and other ophiostomatoid fungi in Ceratocystis and Ophiostoma are unknown. Large subunit ribosomal RNA sequence data was obtained for the fungi associated with Protea infructescences as well as for the type species of Ceratocystis and Ophiostoma. Both groups of ophiostomatoid fungi were phylogenetically distinct from either Ceratocystis or Ophiostoma, despite sharing morphological and physiological characters with these genera. The species of Ophiostoma associated with Protea infructescences group within the Ophiostomatales while species of Gondwanamyces group within the Microascales. Furthermore, the Ophiostoma spp. from Protea should reside in a separate genus and are a fascinating example of convergent evolution towards insect dispersal.

The Cainiaceae is revived to accommodate Atrotorquata, Arecophila, Cainia, Ceriophora and Reticulosphaeria, all of which are described and illustrated. Ommatomyces is also included in the family and discussed. The essential characteristics of the family are ascomata which are usually immersed under a clypeus, unitunicate asci with a complex, J+, apical apparatus comprising a series of rings, and brown ascospores which may have longitudinal germ slits, striations, reticulate ornamentations and/or germ pores.

Cryptovalsa mangrovei is described and illustrated as a new species from a wood test block submerged in the intertidal zone of Mai Po Mangrove in Hong Kong and compared with C. halosarceiicola, another mangrove species, and C. suaedicola from an intertidal salt marsh plant.

Some Armillaria species cause major disease problems in both forestry and gardens. In order to determine routinely and rapidly the identity of an isolate, a PCR-based method was investigated. A fragment, approx. 900 bp, of the IGS region of the ribosomal DNA was amplified from 96 different isolates of six species of Armillaria collected from the U.K. and mainland Europe. Armillaria mellea, A. gallica and A. tabescens produced unique digestion patterns when the PCR fragment was restricted with Alu I. A. ostoyae could be distinguished from A. borealis and A. cepistipes when the PCR fragment was restricted with Bsm I. Previously unreported RFLP patterns were determined for A. mellea and A. gallica. The existence of A. gallica isolates which are putative heterozygotes for the rDNA cluster is also reported. Based on differences in banding patterns. A. mellea, A. gallica, A. cepistipes and A. borealis were subdivided further into groups which correlated with differences in cultural morphology.