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.

Changes in conidial numbers of aquatic hyphomycetes in water passing through a concrete pipe were investigated by water filtration. Retention in the pipe was low and concentrations of conidia of Alatospora acuminata, Anguillospora longissima, Clavariopsis aquatica, Clavatospora longibrachiata, Heliscella stellata, Lemonniera terrestris, Lunulospora curvula, Pyricularia submersa, Tetrachaetum elegans and Tetracladium marchalianum were unchanged after 1·8 km drift. Only one species, Articulospora tetracladia, showed significant decrease, resulting in part from fragmentation of the conidia. These results suggest that studies of communities of aquatic hyphomycetes in natural environments by sampling conidia by water filtration need to account for differences in stream retention as well as species specific differences in conidial fragmentation.

Wheat bran, cassava bagasse and sugar cane bagasse were shown to be adequate substrates for the growth and aroma production by the mould Ceratocystis fimbriata. Among the nutritive media tested, sugar cane bagasse complemented with a synthetic medium containing glucose (200 g l−1) gave a fruity aroma while the leucine or valine-containing medium gave a strong banana aroma. Aroma production was dependent on growth and the maximum aroma intensity was detected at about the time of the maximum respirometric activity. Twenty-four compounds have been separated by GC headspace analysis and 20 were identified, among them: 1 aldehyde, 7 alcohols, 4 ketones and 8 esters. It was clearly demonstrated that the chromatographic profile of the headspace of the culture was dependent on the substrate used and on the eventual precursor added. When leucine or valine was added to the substrate, the production of total volatiles in the headspace reached values up to tenfold higher than that for ripe bananas. The Gompertz model, a logistic-like equation, was used to fit the integrated CO2 and volatiles production data.

3- and 7-hydroxyflavone and their acetic acid esters were tested against Cladosporium herbarum and Penicillium glabrum for antifungal activity. The effect of the hydroxylated flavones was relatively low whereas the ester derivatives were substantially more active.

Restriction fragment length polymorphisms (RFLPs) were identified among total DNA from clonal lines of Uncinula necator when cloned sequences of total U. necator DNA were used as probes. Four probes, pUnP14, pUnP27, pUnE21 and pUnE4, hybridized to multiple-copy sequences and, with the exception of pUnE4, detected genetic variation among clonal lines of U. necator. Clones pUnP14, pUnP27 and pUnE4 produced banding patterns that were stable for DNA extracted from different asexual generations of U. necator clonal lines over at least 15 months. In addition, clones were evaluated for species specificity. Clones pUnP27 and pUnE4 detected only U. necator sequences in total DNA from infected grapevine leaves. Clones pUnP14 and pUnE4 did not hybridize to total DNA from a range of fungi.

Genetic diversity in a sample of the Australian U. necator population was investigated; 15 genotypes were identified among 29 U. necator clonal lines examined. Genetic variation was detected in samples collected within micro-geographical areas, for example, different genotypes representing both mating types of U. necator were detected on a single plant of Vitis amurensis. RFLP analysis of the banding patterns produced using pUnP14, pUnP27 and pUnE21, identified two broad genetic groups, designated A and B. Analysis of DNA fragment patterns obtained using the polymerase chain reaction (PCR) and the plant intron splice junction (ISJ) primer R1 also supported the allocation of U. necator clonal lines into groups A and B.

Mycelium grew from a spore-mycelial inoculum of Aspergillus oryzae added to ultra-pure water (upw) containing silicon compounds, but did not grow in upw alone. Growth of other fungi also occurred in upw only when silicon compounds were added. Increased growth of A. oryzae, and other fungi, also followed the addition of silicic acid and other silicon compounds to Czapek Dox. Aspergillus oryzae solubilized silicon compounds in both upw and nutrient-rich media. Although interactions between microorganisms and silicon have been generally neglected, the results show that silicon compounds can increase fungal growth under both oligotrophic and nutrient-rich conditions.

The current distribution and host range of the Sclerotiniaceae indicate that the family originated in the Northern Hemisphere. The ancestors were possibly present on earth during the Tertiary period when, in most northern areas, environmental conditions were wet, warm and uniform until the approach of the Pleistocene epoch. It seems from present-day host–pathogen relationships that some ancient groups of plants and a variety of angiosperms were hosts. The teleomorph of early genera was well adapted to wet conditions, with ascospores the only dispersive spore and microconidia probably serving a spermatial function. Macroconidia were probably later evolutionary developments associated with colonization of habitats drier than the original one. The onset of the Pleistocene Ice Age would have exerted considerable environmental pressures on early genera resulting in selection of adaptations which enabled survival of the gradually changing conditions, particularly sub-zero temperatures and unavailability of hosts during the harsh winter months. The major adaptations in the Sclerotiniaceae have been a range of multihyphal, reserve-rich resting structures which survive harsh environmental conditions and provide nutrients and protection for the teleomorphs, which are highly sensitive to cold and desiccation. The resting structures are useful indicators of phylogenetic relations within the family. Information on stromata and sclerotia of the Sclerotiniaceae is reviewed and then used to discuss evolution of these structures. The first type of resting structure to evolve was probably an indeterminate stroma which developed by branching and interweaving of infection hyphae within host tissues. Several, better differentiated forms were produced with their morphology related to type of host and tissue infected and to characteristics of the pathogens. The different stromata could have evolved along a common pathway or independently. The general anatomical similarity of the various structures could be accounted for because of the limited structural forms that can be produced by interweaving of filamentous hyphae. It seems that sclerotia may have developed from hyphal tissue which had the ability to produce sclerotia when the climate was cold and wet, and macroconidia when conditions were warmer and drier. Two main types of sclerotia are distinguished, tuberoid sclerotia and plano-convex sclerotia. The literature relating to the morphology and ontogeny of macroconidia is reviewed and used for speculation on the effects of environmental conditions on evolution of macroconidia, the origin of macroconidial anamorphs and stages in the evolution of botrytoid spores. It is concluded that in the Sclerotiniaceae there are at least two main pathways along which resting structures have evolved, one leading to a variety of stromata and the other to two types of sclerotia. Sclerotia predated macroconidia and both anamorphs could have originated from common generative tissue.

Intact ungerminated spores or germinating swollen spores of Mucor circinelloides were biolistically transformed to leucine prototrophy with the autonomous replicating plasmids pLeu4 and pMCL1302. The former developmental stage was efficiently transformed with both plasmids. The existence of pLeu4 sequences, as selfreplicating elements, within Leu+ transformants was established by Southern analysis and by the recovery of plasmid pLeu4 in bacteria transformed with total DNA from M. circinelloides transformants. This is the first report of the transformation of intact cells of a member of the Zygomycetes.

A study of the macroscopic and microscopic characters of type material of Tulostoma leiosporum, T. exitum, T. operculatum and T. puncticulosum showed their heterogeneity. An attempt was made to resolve the taxonomic problems involved in the selection of lectotypes, and new synonymies are proposed. SEM photographs of spore ornamentation are provided.

A method to effect rapid, near-synchronous colonization of tomato root systems by a vesicular arbuscular mycorrhizal fungus was developed. This procedure was used to compare the time course of colonization in roots of tomato that were grown under varying phosphate conditions. It was found that the primary symbiotic interaction developed through a series of regularly timed stages. Furthermore, the formation of intercellular hyphae, arbuscules and vesicles was significantly reduced in plants grown with high soil phosphate. These results show that this method is ideal for the production of material for molecular biological studies of VAM symbiosis, including investigation of the regulatory role of phosphate in the symbiosis and the processes that control the fungal life cycle.

The fungal pathogen Entomophaga maimaiga, infecting gypsy moth larvae (Lymantria dispar), produces two types of spores; relatively short-lived conidia are produced externally on cadavers and are actively ejected to cause infection during the same season, while azygospores, produced within cadavers, are dormant after formation and survive unfavourable conditions. This is the first record providing experimental proof of differential reproduction resulting from infections initiated by these two types of spores. Cadavers of larvae that had died from infections initiated by azygospores produced only conidia, regardless of host instar or relative humidity after host death. This is in stark contrast to infections initiated by conidia, which could yield either conidia only, azygospores only, or both spore types, with reproductive outcome primarily influenced by host age. Production of only conidia from infections initiated by azygospores increases opportunities for secondary transmission during the eight week field season; if infections initiated by azygospores produced azygospores, chances for amplification of infections with subsequent epizootic development would be decreased.

Previously undescribed features on the surfaces of powdery mildew conidia were revealed by the scanning electron microscope (SEM), reinforcing differences observable by light microscopy (LM). Four distinct patterns were observed on the septa and 10 on the outer wall, thus categorizing 15 anamorph taxa. Anamorphs of Leveillula, Phyllactinia and Pleochaeta, all had smooth to moderately verrucose septa, but each bore a different distribution of warts on their verrucose outer wall. Annular septa and an echinulate outer wall were unique for the Oidium anamorph of Blumeria. The remaining powdery mildews, all with Oidium states, had either whorled or fibrillar septa. Those with whorled septa are separated into three newly proposed subgenera: Fibroidium for the anamorphs of Podosphaera and Sphaerotheca having conidia with fibrosin bodies and a smooth outer wall; Octagoidium for the dendritic patterned, eight-sided conidia of Sawadaea; and Setoidium for the anamorph of Cystotheca reflecting the setae on the mycelium. Three new subgenera are proposed for those with fibrillar septa: Reticuloidium for conidia with a roughcast outer wall of Erysiphe sect. Golovinomyces; Graciloidium for the unswollen conidia of Arthrocladiella; Striatoidium for conidia of E. sect. Galeopsidis with a striate outer wall. The name Pseudoidium is retained as a subgenus for the anamorphs of E. sect. Erysiphe, Microsphaera and Uncinula which had conidia with a scaly, fibrous outer wall. The patterns on the outer wall of conidia were frequently modified by secondary creasing. These wrinkling patterns, also observable under the LM, proved useful in identification of anamorphs, especially on herbarium specimens. SEM, LM and host range data were used to construct keys for the prediction of the anamorphs of all the powdery mildew genera found in the U.K. The findings, together with teleomorph criteria, also prompted a revision of the Erysiphaceae.

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.

This listing covers the period November 1, 1996 through to November 30, 1996. Citations are arranged in groups which roughly correspond with the British Mycological Society's Special Interest Committees.

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