Variation in Gremmeniella abietina var. abietina was studied in three stands of Scots pine in northern Finland and in the Kola Peninsula. Eighty-four isolates of large- and small-tree types of G. abietina var. abietina (LTT and STT, respectively) were identified on the basis of tentative characteristics (spore morphology, disease type and host size), fatty acid and sterol profiles (FAST), and random amplified microsatellite technique (RAMS). Both LTT and STT occurred in all three stands. In general, the classifications obtained using the three methods agreed with one another, although a few contradicting results were observed. Variation in fatty acids and sterols in G. abietina var. abietina was rather low, although the amounts of some individual extractives showed statistically significant differences between the stands. All pathogenic and asymptotic G. abietina var. abietina isolates originating from branches located at heights above the annual snow cover were identified as LTT based on RAMS, but some were grouped to STT according to their FAST profiles. Both STT and LTT were detected among the isolates obtained from seedlings according to both FAST and RAMS. In addition, in two cases RAMS markers thought to be STT- or LTT-specific were found in the same isolate. The results presented here suggest that LTT of G. abietina var. abietina caused the devastating epidemics on pines in the first-thinning stage or middle age similar to pines in this study reported in northern Finland and in the Kola Peninsula during the 1980s.

The genus Leptographium was described in 1927 and currently includes 48 species, with L. lundbergii as the type species. In recent years, the taxonomic status of L. lundbergii has not been uniformly agreed upon and it has been the topic of considerable debate. The problem was compounded by the absence of a type specimen, and the species was epitypified at a later stage. Unfortunately, the whereabouts of the epitype is now unknown. In 1983, Wingfield & Marasas described L. truncatum, which is morphologically similar to L. lundbergii. Based on DNA comparisons and similarities in their morphology, this fungus was reduced to synonymy with L. lundbergii. The loss of the type specimen as well as variation in the morphology of strains identified as L. lundbergii prompted us to re-examine the taxonomic status of this species. A number of strains from various geographic areas were studied. These include a strain of L. lundbergii deposited at CBS by Melin in 1929 (CBS 352.29) as well as the ex-type strain of L. truncatum. The strains were compared based on morphology and comparison of multiple gene sequences. Three genes or genic regions, ITS2 and part of the 28S gene, partial β-tubulin and partial elongation factor 1-α were compared. Strains currently identified as L. lundbergii, represented a complex of species. Strains initially described as L. truncatum clustered separately from other L. lundbergii strains, could be distinguished morphologically and should be treated as a distinct taxon. L. lundbergii is provided with a new and expanded description based on a neotype designated for it. A third group was also identified as separate from the main L. lundbergii clade and had a distinct Hyalorhinocladiella-type anamorph, described here as H. pinicola sp. nov.

Genetic characterization of 15 aggressive weed mould strains that were identified morphologically as Trichoderma harzianum (sensu Rifai) from mushroom compost in commercial units in North America (designated T. harzianum group 4) was undertaken using various molecular techniques. RFLP analysis of rDNA revealed homogeneity among these strains; a low level of polymorphism was detected in mitochondrial DNA. RAPD analysis also indicated a very high degree of homogeneity among the T. harzianum group 4 strains. Nucleotide sequence determination of the rDNA internal transcribed spacer (ITS) 1 revealed five base pair differences between T. harzianum groups 4 and 2. Comparison of molecular data on T. harzianum group 4 with that of T. harzianum group 2, which caused green mould epidemics in the mushroom industries of the British Isles, indicated that T. harzianum group 4 is not the same as group 2.

Species delimitation is still controversial in the Xerocomus chrysenteron complex. We have therefore established comprehensible and reliable species concepts based on statistical evaluation of morphological and ecological characters. We examined many collections from different geographical regions and different developmental stages within collections. Quantitative micromorphological characters (basidiospores, pileipellis end cells) were measured in statistically relevant numbers. The same material was used to generate 24 rDNA-LSU sequences, and the results of phylogenetic analyses clearly confirmed our species concepts: spore size and ornamentation, length of the pileipellis end cells and ‘pruinatus-hyphae’ are most valuable characters for the delimitation of species in this complex. Molecular data demonstrated that the X. chrysenteron complex is a monophyletic group. All the examined species (X. chrysenteron, X. cisalpinus, X. pruinatus, X. ripariellus, X. dryophilus, X. fennicus, X. porosporus, and X. rubellus) represent independent lineages. The faintly striate spores, a key character characterising species of section Striatulispori, probably evolved independently. In addition, the ‘pruinatus-hyphae’ have multiple origins, and truncate spore apices are derived at least twice. Xerocomus cisalpinus sp. nov. is characterised by striate spores, the presence of ‘pruinatus-hyphae’ and a pileipellis strongly reminiscent of X. chrysenteron. For reasons of discussion, microscopical data are presented on Boletellus episcopalis for the first time. Xerocomus fennicus (Boletellus) comb. nov. is proposed. We provide descriptions to all included taxa. Our results once more demonstrate that reliably identified and characterised voucher collections are the basic requirement for meaningful phylogenetic studies.

Sordaria brevicollis is a filamentous ascomycete previously considered to be exclusively heterothallic. Here we show that S. brevicollis can exhibit homothallism, and describe the genetic and environmental factors favouring the process. Both mating types can produce perithecia in unmated cultures, but only in the uncrossed perithecia of mtA are ascospores formed (in <30% of the fruitbodies). In most cases, only one or two asci are produced in any uncrossed mtA perithecium, although as many as 13 have been observed. The ascospores show no segregation for mating type; all are mtA. Heterokaryon analysis established that meiosis and recombination occurred during ascospore production in both homothallic and heterothallic development. Homothallic fruiting is inhibited both by crossing with the opposite mating type, and by light.

Three species of fossil epiphyllous coelomycetes are described from Dominican and Mexican amber in the new genera, Asteromites gen. nov., Leptostromites gen. nov. and Leptothyrites gen. nov. Characters of the pycnidia and spores most closely resemble members of their extant respective genera, Leptostroma, Asteromella, and Leptothyrium, respectively. A. mexicanus sp. nov. occurs on a petal (possibly from a caesalpinoid legume such as Peltogyne) in Mexican amber. Leptostromites ellipticus sp. nov. occurs on a dicot leaf in Dominican amber, and Leptothyrites dominicanus sp. nov. on a monocot (grass?) leaf in Dominican amber.

Eighty-eight isolates of Gremmeniella abietina var. abietina belonging to the Asian, European and North American races were cultivated on agar plates and their fatty acids and sterols were extracted and analysed.

Fourteen fatty acids and seven sterols were detected by gas chromatography. Multivariate discriminant analysis revealed distinct differences between the contents of fatty acids and sterols (FAST-profiles) of the three races; the most distinct was the Asian race. Additionally, the presence of two ecologically different types in Finland, the large tree and small tree type (LTT and STT, respectively) was confirmed on the basis of their significantly different FAST-profiles. The FAST-profiles of European STT more closely resemble the American race than the European LTT. The diversity of North American isolates of the European race, which were supposedly initially introduced from Europe in the 1960s, were considerably higher than the diversity of the European LTT or STT isolates.

Teliospores, basidia, cultures, hyphal septations, cellular interactions and nucleotide sequences from the D1/D2 region of the nuclear large subunit ribosomal RNA gene of Entyloma ossifragi occurring on Narthecium ossifragum (Nartheciaceae) were examined and compared with findings in the Georgefischeriales and other Ustilaginomycetes. The data show that Entyloma ossifragi is a member of the Georgefischeriales. Among the Georgefischeriales, Entyloma ossifragi morphologically is very similar to Jamesdicksonia species, but differs from this genus and all other Georgefischeriales by the formation of dolipores without striations that become closed during teliosporogenesis. In addition, in our molecular phylogenetic analyses Entyloma ossifragi stands well apart from Jamesdicksonia, forming with some Tilletiopsis specimens a statistically supported cluster. Accordingly, the genus Gjaerumia gen. nov. and the family Gjaerumiaceae fam. nov. are proposed to accommodate Entyloma ossifragi in the Georgefischeriales. The new combination G. ossifragi (syn. Entyloma ossifragi) is made.

The biological relationships of lichenicolous fungi and their hosts are studied in four members of the Dacampiaceae. Infections of the lichenicolous species Dacampia engeliana induce in its host Solorina a thallus morphology similar to that found in the lichenized D. hookeri. D. engeliana, however, differs microscopically by hyphae growing inside those of Solorina in the algal layer and the medulla. Pyrenidium actinellum develops short haustorial structures into the hyphae of the host. These haustoria are characterised by finger-like outgrowths into the host cells. Clypeococcum hypocenomycis forms dense brown mycelia in the upper cortex of the host, which is progressively destroyed. These lichenicolous parasites have a preference for the fungal symbiont of the host lichen and, in contrast to several other lichenicolous fungi, the algal partner is not primarily affected. The various types of infection modes found in the family Dacampiaceae suggest that a great variation of infection modes may exist in further groups of lichenicolous fungi. Other infection types are included in the discussion.

The suitability of random amplified polymorphic DNA for identification of Pythium aphanidermatum was investigated. Three oligoprimers were selected after testing three isolates of P. aphanidermatum and one isolate of P. ultimum with a total of 40 primers. The selected 10-mer primers were used with 20 isolates of P. aphanidermatum, four isolates of P. deliense, two isolates of P. ultimum, two isolates of P. irregulare and one isolate of P. paroecandrum. Most of the P. aphanidermatum isolates (13 of 20), were obtained from samples of Cucumis sativus, or water from cucumber greenhouses. The three selected primers gave identical fingerprints for 18 of the 20 P. aphanidermatum isolates, including all the isolates from cucumbers. Two of the primers gave fingerprints that could be used to differentiate between isolates of the Pythium species studied. The banding pattern of P. aphanidermatum given by the third primer could not easily be distinguished from the fingerprint of P. deliense. However, when used in conjunction with the other two primers, the third primer can be used to verify the identity of P. aphanidermatum.

We examined the phylogenetic position of Omphalina foliacea and its putative closest relative, the lichen-forming basidiomycete Lichenomphalia lobata. Both species are restricted to specific habitats in the high andine regions of tropical America. We generated nuclear ITS and LSU rDNA sequences of two collections of each species and analysed the data together with sequences of omphalinoid basidiomycetes retrieved from GenBank using a Bayesian and a maximum parsimony approach. Our analyses show that both, O. foliacea and L. lobata are lichenized basidiomycetes. L. lobata is related to other species of the genus Lichenomphalia, whereas O. foliacea is not closely related to other Omphalina or Lichenomphalia species, but probably belongs in the hymenochaetoid clade. The analysis of a nuclear LSU data set of a broader sampling of hymenochaetoid basidiomycetes supported the placement of O. foliacea in this clade, but did not reveal any close relative.

An unknown species of Ophiostoma was isolated from European larch (Larix decidua) infested by Tetropium gabrieli (Coleoptera: Cerambycidae) and Norway spruce (Picea abies) infested by Tetropium sp. in Austria. The fungus is similar to O. minus, but distinguished from it by the ecology, colony morphologies on OA and MEA, and phylogenetic analysis of aligned DNA sequences of the ITS region of the rDNA operon and the partial β-tubulin gene. It is described here as O. kryptum sp. nov. The new species readily produces perithecia with short necks and reniform ascospores, and has Hyalorhinocladiella and Leptographium-like anamorphs. Circumstantial evidence suggests that Tetropium spp. act as vectors of O. kryptum. O. minus and O. kryptum represent additional examples of morphologically similar, yet genetically and ecologically distinct species in the genus Ophiostoma. The new combination, O. crenulatum comb. nov. (syn. Ceratocystiopsis crenulata), is also made.

Seventy-one strains of fungi belonging to 53 species of Zygomycota and mitosporic fungi were isolated from soils containing different levels of 2,4,6-trinitrotoluene (TNT). Three moderately contaminated samples (500 ppm) and an uncontaminated control contained a rich diversity of species whereas few fungi were isolated from a heavily contaminated sample (1000 ppm). Most isolates were capable of biotransforming TNT into aminodinitrotoluenes and azoxy-dimers, although they differed widely in their tolerance of TNT. Spore germination was generally more strongly inhibited by TNT than hyphal growth. Among the Zygomycota, Absidia and Cunninghamella were highly TNT-tolerant and attacked the substrate even when this had precipitated at 1000 ppm, whereas 12 of the 14 Mortierella isolates were intolerant of TNT above 50 ppm. Among the mitosporic fungi, Acremonium, Cylindrocarpon, Gliocladium and Trichoderma but not Penicillium species were highly tolerant of TNT and had a high capacity to biotransform this compound. Large variations in these properties were determined between species and even strains belonging to the same species, and between different isolates from the same soil sample. Populations of soil microfungi therefore show a high natural variation of TNT tolerance and biotransformation ability, irrespective of any previous long-term exposure to this xenobiotic.

Medusoides gen. nov. is described from North Carolina, U.S.A. The fungus reproduces sexually, with oogonia and antheridia, but no asexual stage has yet been found. The fungus has not yet been obtained in culture. The vegetative growth is mycelial but the hyphae are very narrow (<3 μm) with vesiculate nodes. The oospores are strictly plerotic. Oogonial and oospore walls are distinctive with unique ultrastructure. The peronosporomycete is a typical aero-aquatic fungus, having markedly buoyant propagules, due to the possession of long, recurved, oogonial outgrowths covering the oogonium sufficiently densely so as to retain air between them and the oogonial surface after exposure and reimmersion. Its habitat, in the lower layers of submerged deciduous leaf litter, suggests survival in an anaerobic environment and a fermentative capacity. An affinity with Pythiogeton is proposed, and Pythiogeton is made the type genus of a new family, the Pythiogetonaceae.

Fungal biomass was detected in peat soils from throughout the Everglades based on the presence of ergosterol. Ergosterol concentrations in soils were not detectably affected by the dominant plant, Cladium jamaicense or Typha domingensis, or phosphorus content of soils. In situ decomposition of decaying leaves, measured by respiration, was high (maximum 484 μl O2 h−1 g−1 dry biomass). Approximately 30% of respiration was by bacteria, and the rest was by fungi and other eukaryotes. Respiration rates were essentially the same for decomposing leaves of both plant species, with higher rates early in the decomposition process. Respiration rates were relatively unaffected by the nutrient status of the site, except for eukaryotic respiration on Cladium, which was usually higher at a high nutrient site. Ergosterol concentration increased in decaying leaves through time and was unrelated to the nutrient level except for Cladium, where it was higher at the high nutrient site. Eukaryotic respiration was not correlated with ergosterol concentration in decomposing leaves of Typha, but was positively correlated with ergosterol for Cladium.

The green fluorescent protein gene was inserted into isolates of the endophyte Neotyphodium lolii from perennial ryegrass Lolium perenne using the method with polyethylene glycol treatment of protoplasts. The transformation rate was 3·2×10−6 of the original number of protoplasts 5 weeks after the transformation. Freshly isolated mycelium from the host plant was used in the transformation experiments, since difficulties of infecting the host plant with older isolates were observed. Isolates were identified using the universal primed (UP) PCR fingerprinting method.

The transformed mycelium readily expressed the green fluorescent protein gene. Fluorescence was observed in the cytoplasm of the mycelium cells in pure culture, both before infection and after re-isolation from the host plant. The fluorescent hyphae were easily detected in the host plant. No disturbing autofluorescence from the host plant leaf sheaths or from the wild type isolate was observed. The importance of mitotic stability is discussed, based on the transformed phenotype and southern hybridization pattern, since the Neotyphodium lolii transformants lost 1–2 copies of the integrated gene after re-isolation from the host plant without losing their GFP phenotype. This is the first report on transformation of a Neotyphodium sp. with a gfp gene. In the future, the green fluorescent protein may serve as a tool for studying gene expression and protein localization in the endophyte/host plant interaction using heterologous fusion proteins.

Isolates of Verticillium nigrescens and V. tricorpus were obtained from potato, cotton, eggplant, weeds and field soil in Israel. Chlorate- resistant nitrate-nonutilizing (nit) mutants were generated from each isolate and used in complementation (heterokaryon) tests. Eleven vegetative-compatibility groups (VCGs) were found among 19 V. nigrescens isolates from nine sites, and nine VCGs among 26 isolates of V. tricorpus from eight sites. Optimal growth temperature was 24–27°C for V. nigrescens and 24° for V. tricorpus. None of the isolates caused leaf symptoms or stunting in inoculated eggplant and cotton seedlings, while severe symptoms were caused by V. dahliae. Colonization of inoculated seedlings by V. nigrescens and V. tricorpus occurred primarily in roots and hypocotyls, while V. dahliae heavily colonized upper stems as well.

A new freshwater ascomycete genus Proboscispora is introduced to accommodate P. aquatica collected on wood submerged in streams in Australia and the Philippines. Proboscispora is characterized by having immersed, ellipsoidal, papillate ascomata, septate tapering paraphyses, cylindrical unitunicate asci with a refractive apical ring, and 3-septate, hyaline ascospores provided with coiled or proboscis-like bipolar filamentous appendages. Proboscispora aquatica is illustrated at the electron microscope level and is compared with Annulatascus, Ceratosphaeria, Ceriospora, Ceratostomella and Rivulicola, with which it shares some common characters.

Comparison of all presently available data on gasteromycetoid structure and development allows reassessment and leads to rectification of some questionable ideas about the relation of gasteromycetes to Agaricales. The gasteroid features which are dealt with are those which are particularly relevant to this subject. Some important, but specifically taxonomic, features are left out of the discussion. The loss of violent spore discharge is the only criterion to characterise basidiomycetes which have been united under the term gasteromycetes. Gasteromycetoid adaptations have probably arisen in the distant past at successive levels of basidiomycete evolution. Sometimes the shape of gasteromycetes is reminiscent of one of the groups from which they have descended and in other cases they have been subjected to an unique evolution in response to challenge by particular ecological requirements regarding spore dispersal.

A study of the lichenicolous fungi occurring on species of the lichenized genus Peltigera has resulted in six new species: Libertiella curvispora, L. didymospora, L. fennica Alstrup, Polycoccum superficiale, Roselliniella peltigericola, and Zwackhiomyces kiszkianus. A key to the five known species of Libertiella is included. This paper brings the number of fungi known on this host to 87, of which 61 are not known from any other host genus, providing additional evidence for the richness of Peltigera thalli as a host for novel fungi. The possible hypotheses to explain the richness of this host genus for lichenicolous fungi are enumerated; these are not mutually exclusive.