Assessment of diversity (including both species richness and intraspecific variation) within a habitat may often be difficult when morphological criteria are used for identification and classification of isolates. Here we describe how combined fatty acid and sterol profiles (FAST-profiles) can be used for classification of fungal isolates into FAST-groups (i.e. operational chemotaxonomic units) according to a defined upper variation limit. Data analysis includes a two stage statistical approach. First, the isolates are grouped into taxonomic species using a discriminant model based on well identified ‘model’ isolates. These species groups together with one group that includes isolates which could not be identified with the discriminant model are further divided into operational chemotaxonomic units using a FAST-profile mismatch threshold. This method is demonstrated with Norway spruce needle endophytes.

The model isolates were obtained from fallen spruce needles and identified by morphological criteria. Five species fruited on the needles: Lophodermium piceae, Rhizosphaera kalkhoffii, Lirula macrospora, Tiarosporella parca, and Thysanophora penicillioides. Additionally, mycelia of Sclerophoma pythiophila were frequently noted. These model isolates were separated by their FAST-profiles by applying a multivariate discriminant model into six distinct non-overlapping clusters corresponding to their species. This model was used for identification of 1740 isolates obtained from surface sterilized Norway spruce needles. As an example, isolates identified as T. parca were further divided into FAST-groups by applying a FAST-profile mismatch threshold value. This threshold value was the average within-species mismatch-value obtained for isolates identified by morphological criteria. This method allows a division of any batch of fungi cultivable in vitro into operational chemotaxonomic units according to a defined upper variation limit.

Cheiromycina globosa and C. ananas spp. nov. are described in the lichenized hyphomycete genus Cheiromycina, one from Germany and one from the USA. A key is provided to all four species now known in genus, and all other lichenized hyphomycetes are briefly mentioned. All are corticolous and rarely recorded, so far only from temperate regions in Europe and North America.

Myriogenospora atramentosa produces partial to complete sterility of host grasses. Geographical and host species distributions were assessed and updated. It is reported only from the New World and appears to be limited to the highly evolved grass tribes Andropogoneae and Paniceae. Included in these tribes are the previously unreported host species Panicum scoparium, Paspalum urvillei, Erianthus brevibarbis, E. contortus, E. giganteus, and hybrids from crosses with Erianthus spp. Additionally, M. atramentosa is reported for the first time growing on Paspalum notatum (bahiagrass), and Panicum hemitomon in South Carolina, U.S.A. Sequence data (ITS regions 1 and 2 and 5·8S rDNA) from several isolates indicated that there is a significant level of DNA sequence differentiation between isolates of M. atramentosa, which suggests that there are at least two distinct sequence groups, or cryptic species, within the currently defined morphological species.

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.

Morphological variation of germ tubes originating from aeciospores of Peridermium pini and Cronartium flaccidum populations on Pinus sylvestris was investigated in rust populations from Finland, the United Kingdom and Italy. The observed morphological variation was generally higher among than between these rust populations. The variation in germ tube length of the rust samples was high over the incubation period. Peridermium pini could not be distinguished from C. flaccidum based on its germ tube morphology.

Moelleroclavus is considered to be an anamorphic genus. The teleomorph of M. penicilliopsis is shown through field observations, collection examination, and cultures to represent a previously unnamed species of Xylaria, X. moelleroclavus sp. nov. Xylaria lingua and X. scruposa are also discussed.

Two new species of Hymenochaetaceae, Phellinus fushanus sp. nov. and Inonotus fushanus sp. nov., found growing saprotrophically on the stem of Persea zuilhoensis and Quercus longinus, respectively, in Taiwan, are described and illustrated.

A method to identify the earliest stages (initials) of Pleurotus pulmonarius and Coprinus cinereus fruit body formation was developed. Light microscopy and Cryo-SEM were used to confirm that even the smallest structures to take up stain were initials of fruit bodies. An approach combining histological staining (flooding the Petri dish with 1% toluidine blue in 1% boric acid (w/v) for 15 min) and image analysis allowed the number of fruit bodies formed on Petri dishes to be quantified easily. Use of the vital stain Janus green (0·001% aqueous, w/v) allowed continued observation of living tissue so that the proportion of fruit bodies that matured (30%) could be established. The method was also effective on wheat straw cultures and could be used to monitor development of mature fruit bodies. It is a promising tool in the study of physiological processes involved in fruit body initiation.

Eight new species of ascomycete, Anthostomella longispora sp. nov., Capronia glabra sp. nov., Dictyonella circinata sp. nov., Guignardia castanopsis sp. nov., G. clematidis sp. nov., Hysterographium longisporum sp. nov., Ophiodothella arengae sp. nov. Saccardoella miscanthi sp. nov. from Taiwan are described, illustrated and compared with closely related taxa. Keys to Anthostomella species on Smilax and to the recognized species of Dictyonella are also provided. The two Guignardia species are also associated with Phyllosticta anamorphs.

Isolates of Pleurotus cystidiosus and P. smithii were studied to verifie the occurrence of P. cystidiosus instead of P. smithii in South America. The two species are mainly separated by the growth rate of the anamorph in culture, the morphology of the anamorph and teleomorph, intercompatibility tests, and genetic variability. In order to see if the isolate found in Brazil and previously identified as Antromycopsis macrocarpa (the anamorph of P. cystidiosus) belongs to P. cystidiosus, a species with a world wide distribution, or to P. smithii which is restricted to Mexico and South America, or if P. cystidiosus and P. smithii are the same species, isolates of different geographic origins were studied. Growth rate in culture, mono-dikaryotic matings, and genetic variability determined by RADP were investigated. The results show that the criteria used to separate the two species are unsatisfactory, and that P. smithii should be considered a synonym of P. cystidiosus; this extends the distribution of this later species to Central and South America.

Somatic cells of Armillaria gallica fruit bodies have been shown to possess different genotypes for molecular-marker and mating-type loci. Here we report experiments on six quantitative traits and demonstrate that somatic cells of fruit bodies possess almost as much genetic variation for growth rate and phenotypic plasticity as do spores, the products of meiosis. Genetically distinct somatic cells therefore have the potential to grow at different rates relative to one another during primordial fruit body formation. This may confer an advantage on all cell lines within a fruit body, not just those that happen to grow better under a particular set of conditions. To our knowledge, genetic variation for fitness-related traits that make up a single genetic individual has not been reported before.

Arbuscular mycorrhizal (AM) fungi are obligate biotrophic organisms. Root organ culture (ROC) can be used to grow these fungi under in vitro conditions. The ROC technique was used with Gigaspora margarita and Ri T-DNA transformed carrot roots to examine the fungal growth and physiology under long-term axenic symbiosis. The fungus formed spores inside the host roots under in vitro conditions. Sporulation was a temporal phenomenon found in dual cultures more than 18–20 mo old. The spores were formed singly or in rare cases clusters of two or three. No preferential zone of formation was found. The spores formed intraradically were 10–15% of the total spores formed in a single culture. These intraradical spores were analysed for their morphology and DNA polymorphism pattern with spores which had formed conventionally in the medium. Both analyses showed no detectable variation. This is the first report of spore formation by Gigaspora inside the roots of a host.

Growth and interactions of Piptoporus quercinus were studied in artificial culture to give insights into the ecological characteristics of a species which is both rare and widespread. P. quercinus grew slowly under all conditions, the maximum ranging between 1.9 and 3.15 mm d−1, depending on isolate, at 25 °C pH 3.75. Upper limits for growth were 25–30 ° or above 30 °, depending on isolate, and pH 6.6. Lower limits for growth were 5–10 °, between −1.75 and −2.5 MPa; there was still growth at pH 1.81. Preincubating plates at 5 ° for 77 d and then incubating at 20 ° resulted in a significantly greater extension rate (2.89 mm d−1) than when incubated continuously at 20 ° (1.70 mm d−1) for one isolate though not for another isolate. P. quercinus survived exposure to low temperature (−18 ° for 7 d), showing renewed growth, albeit limited, after a lag of 37 d. It was a poor combatant, being unable to replace any of the eight fungi (with a range of ecological roles) against which it was paired, and being replaced or partially replaced by most, on 2% MA at pH 5.49, at pH 3.75 and at −1.25 MPa. It did, however, inhibit extension rate of some other heart rot fungi. Results are discussed in an ecological context.

Contour-clamped homogeneous electric field has been applied to analyse genome size and organisation of two important pathogens of barley, Pyrenophora graminea and P. teres.

Electrophoretic karyotypes of four P. graminea isolates resolved 6–8 chromosomal bands, depending on the isolate, while the one P. teres isolate analysed contained six chromosomal bands. Chromosome length polymorphism was observed among P. graminea isolates. For both fungi the chromosomes ranged from 1.6 to more than 6 Mb, with chromosomes larger than 6 Mb migrating as a single band within the compression zone of the gel.

This paper reports a study aimed at gaining new information on the molecular composition of fruitbodies of Tuber spp. The presence of proteins homologous to TBF-1, which is highly specific for the fruitbody-phase of Tuber borchii, has been investigated in other white truffles. SDS-PAGE analyses revealed that only Tuber dryophilum fruitbodies possess a similar protein. This protein was purified by HPLC and partially sequenced, confirming a high degree of homology with TBF-1. Several PCR analyses of the genomic DNA, were performed to evaluate whether the absence of proteins homologous to TBF-1 in other white truffle species was a result of the absence of the coding genes. T. dryophilum gave an amplification product corresponding to the entire gene (tdf-1), but no products were obtained from the other species. Tdf-1 was sequenced and its organisation studied since it is one of the first genes isolated from a Tuber species. The deduced amino acid sequence was compared to that of TBF-1, to evaluate the presence of conserved regions, in an attempt to gain new information about their role in fruitbody formation.

The hyphal wall protects the pressurized cell against lysis, physical abrasion, chemical damage, and probably from other microorganisms and predatory invertebrates. Against these assets we can hypothesize costs for a cell that are associated with a wall. For example, phagocytosis is impossible, and the release of secreted molecules is complicated by the diffusional challenge presented by the mesh of microfibrils and interleaving wall polymers. A more controversial idea is that once delimited by a tough integument, growth becomes dependent upon the exertion of internal force to cause wall yielding, and most mycologists have posited turgor pressure as the origin of this force. In relation to growth then, it seems logical to suggest that fungal walls evolved to meet a multitude of needs, and that once a cell became walled, osmosis would automatically generate the turgor it required for growth.

The effects of liming on the composition of the mycoflora of dead, lying wood in a Scots pine stand on acid, nutrient-poor soil was studied after 5 yr. Liming led to a significant increase in species number. Amphinema byssoides, Hyphoderma puberum, Hyphodontia breviseta, Hypochnicium geogenium, and Sistotrema octosporum significantly increased, whereas Botryobasidium subcoronatum and Trechispora farinacea significantly decreased after liming. The proportion of species that are characteristic for coniferous wood decreased, whereas the proportion of indifferent species and species that are characteristic for deciduous wood increased after liming. Explanations for this species shift are discussed and an increase in nitrogen dynamics in the wood is considered the most plausible explanation. Possible ecological consequences of these changes in species composition are briefly discussed.

One hundred and sixty isolates of ectomycorrhizal agarics, boletes, and related gasteromycetes were examined for 25 morphological and biochemical characters. A wide range of analytical methods are available with which to obtain efficient summaries of the patterns of variation present in data such as these. Agglomerative clustering of 156 isolates and 18 characters for which no data were missing resulted in partitions of the sample corresponding to recognizable taxonomic and ecological groupings. Key characters useful for delimiting these groups are highlighted by means of divisive clustering and classification trees. For example, boletes (Boletinus, Suillus, Xerocomus) and related gasteromycetous allies (Pisolithus, Rhizopogon, Scleroderma) are distinguished by the production of pigment on media containing high levels of glucose. Numerical taxonomic analyses of cultural characters thus can be useful for examining taxonomic relationships, as in the way in which these characters support not only the close relationship between boletes and some gasteromycetes but also the generic circumscriptions of genera such as Laccaria and Lactarius. However, the taxonomic level at which cultural characters prove most effective must be evaluated carefully, in view of the possibility that, in response to selection, cultural characters have evolved in parallel in separate clades. Thus, ecological as well as taxonomic groups were also recognized. Species of both Hebeloma and Laccaria failed to produce pigment, tolerated low temperatures, and metabolized urea. This suggests that great care must be taken in using cultural characters in phylogenetic studies.

Macromycetes recorded from beds of creeping willow, Salix repens, in the northern archipelagos of Shetland and Orkney are listed and discussed. Two components are demonstrated, an arctic-alpine group and one which is more typical of lowland frondose woodland communities in mainland Britain. The importance of maintaining, even encouraging the development of creeping willow beds with their attendant ectomycorrhizal fungi in conservation terms are explored.

Randomly amplified polymorphic DNA (RAPD) markers were used to assess the genetic diversity of isolates of grey snow mould (‘gray snow mold’), Typhula incarnata, taken from infected turfgrasses from 40 different locations in the northern USA. Data from 115 markers using 37 RAPD primers showed 48% polymorphism. The distance coefficients between isolates indicate the wide genetic diversity of T. incarnata across the sample area. Dendrograms generated using neighbour-joining (NJ) bootstrap analyses showed three clades and suggest possible recent colonization from common founder groups. Partitioning of the genetic variance using analysis of molecular variance (AMOVA) of four groups based on geographic locations (Michigan, lower and upper peninsula; Minnesota; Wisconsin) showed that genetic variation attributable among groups and within groups was 12.67 and 87.33%, respectively. No correlation was found between geographic distance and pairwise genetic distance of the groups. High outcrossing and sexual recombination of T. incarnata may well be key factors explaining the genetic variability as shown with the low Fixation index (FST) and high average of genetic diversity per locus within groups.