Dictyocaulus viviparus and Pilobolus coexist in individual elk of the Yellowstone National Park's northern herd. It is suggested that Pilobolus transfers infective larvae to forage grasses, so spreading the lungworm disease.

Topology provides a novel means to describe branching patterns and has not been applied to fungal colonies previously. For any branched structure, various topologies are possible, and these lie between two extremes, a herringbone pattern (main axis with primary laterals) and a dichotomous pattern (highly branched system). We applied topological methods to colonies of Peronospora viciae 48 h after inoculation of Pisum sativum leaves. The methods are based on two simulations, one developed for channel networks such as found in river systems and another for biological systems. Although not a true herringbone form, the Peronospora viciae colonies have a strong herringbone element within their growth pattern. All 25 colonies analysed fell into the random distribution according to the confidence limits calculated from simulations for biological systems. These confidence limits, however, represent the percentile distribution of all simulated networks, and only those structures with a perfect herringbone or dichotomous topology fall outside the range. The tendency of P. viciae colonies towards herringbone growth is reflected by the topological indices for altitude and external pathlength (a(obs)/E(a) and pe(obs)/E(pe), where a=altitude, pe=external pathlength, obs=observed for the P. viciae colonies and E=expected values for random growth), and the slope of the regression analysis for a(obs) and pe(obs). We consider this trend as significant because it was consistent for all but one of the colonies, and implies that growth can be envisaged as an intermediate between random and herringbone topology. It is proposed that initial herringbone growth may reflect a strategy that is aimed at overcoming host resistance, achieving rapid colonisation of infected tissue and maximising the potential for nutrient acquisition. This topology would also increase the likelihood of finding a compatible mating type for reproduction between heterothallic isolates.

A new ascomycete, Iodosphaeria polygoni sp. nov., is described and illustrated from Taiwan. It is compared with the other known species of Iodosphaeria. A key to species is also given.

Of 47 fungi collected from decaying Ocotea wood, 36 exhibited phenoloxidase activity against gallic acid, 40 exhibited it against tannic acid, 33 possessed laccase and 6 possessed tyrosinase. Thus their capacity to produce ligninolytic enzymes indicated that a high proportion of these fungi could cause white rot in Ocotea wood. It was shown that all 21 fungi tested were capable of causing significant weight loss in Ocotea wood blocks in vitro. Basidiomycetes exhibited the greater capacity to cause decay when compared to non-basidiomycetes. The rank order of species in terms of proportional weight reduction in the wood blocks over four months was: Trametes versicolor (28%), Ganoderma australe (16%), Phellinus sp. 2 (15%), Phellinus senex (10%), Stereum ostreum (10%), Loweporus inflexibilis (9%), Stereum hirsutum (8%), P. gilvus (7%), and Schizophyllum commune (2%). The most aggressive non-basidiomycetes, however, were comparable to S. commune, and these were: Cylindrodendrum album (3%), Cylindrocarpon destructans (2%), Daldinia concentrica (2%) and Nodulisporium sp. (2%).

The influence of neighbours on individual performance in natural populations of the lichenized ascomycete Umbilicaria spodochroa was investigated using three different neighbourhood models; the polygon model, the fixed radius model and the nearest neighbour model. The data set consisted of the exact position of the holdfast points of the peltate lichens within 29 sample squares in crowded populations as well as the mass, diameter, and no. of apothecia of all thalli. A total of 11246 individual thalli were sampled and measured. The predictive power of all three neighbourhood models was moderate, but highly significant for the whole data as well as within most individual sample quadrats. The nearest neighbour model had the best predictive success, closely followed by the polygon model. The fixed radius model had approximately half the power of the two other models. We suggest that the difference is due to different degrees of realism in the models. Thallus mass was commonly the performance parameter best predicted, followed by thallus diameter and number of apothecia. The predictive power of the models for these natural populations was comparable to values obtained in several laboratory studies with vascular plants. The predictive success of the three different models was strongly correlated for single populations, indicating different levels of interference in different populations.

Scytalidium thermophilum plays an important role in determining selectivity of compost produced for growing Agaricus bisporus. The objective of this study was to characterise S. thermophilum isolates by random amplified polymorphic DNA (RAPD) analysis and sequence analysis of internally transcribed spacer (ITS) regions of the rDNA, to assess the genetic variation exhibited by this species complex and to compare this with existing morphological and thermogravimetric data. RAPD analysis of 34 isolates from various parts of the world revealed two distinct groups, which could be separated on the basis of the differences in the banding patterns produced with five random primers. Nucleotide sequence analysis of the ITS region, which was ca 536 bp in length, revealed only very minor variation among S. thermophilum isolates examined. Several nucleotide base changes within this region demonstrated variation. Genetic distance values among type 1 and 2 S. thermophilum isolates, as determined by ITS sequence analysis, varied by a value of 0.005%. Molecular analyses carried out in the present study would suggest that isolates within this species complex exhibit genetic differences which correlate well with morphological variation and thermogravimetric data previously determined.

A revision of Amorphomyces was carried out based on an examination of the author's and type material. Detailed study of the development of the female thallus of Amorphomyces italicus revealed a small, lobate, free, external primary appendage. A free appendage appeared to be lacking in all other known species of the genus. The generic circumscription of Amorphomyces is therefore emended. The new species A. hernandoi, parasitizing the marine aleocharid Diglotta mersa, is described from Portugal. Amorphomyces stipitatus and A. trogophloei are synonymized with A. italicus. With additions and changes, Amorphomyces currently includes ten species. All taxa are illustrated with photographs and line drawings, and a key for their determination is provided.

The heterobasidiomycete moss parasites Eocronartium and Jola have figured prominently in theories of the evolution of the rust fungi and of the basidiomycetes. Such theories made implicit assumptions about the moss parasites, although very little of their life history was known. This is the first in a series of studies to elucidate the life history of the moss parasites. Polyspore monokaryotic cultures were obtained from basidiospores, and dikaryotic cultures were obtained from hyphae inside the moss host plant. In culture, the moss parasites produced Sporothrix-like anamorphs. The uninucleate conidia germinated by a germ tube, by production of single secondary conidia, or by iterative germination. Conidial-hyphal fusion was observed. A dikaryon was produced by mating single conidial isolates of Eocronartium muscicola, completing a part of its life history. Ultrastructural characteristics of wall break at branching, condensed chromatin during interphase, and simple septal pore morphology from fruiting bodies of Jola spp. and cultured isolates of Jola javensis and E. muscicola were consistent with those of related auricularioid phytoparasitic taxa, the rust fungi, and Pachnocybe ferruginea. Jola and Eocronartium can be grown in axenic culture and are not obligate parasites. In nature, the Sporothrix-like anamorph of these fungi may function in dispersal and mating. The previously unknown anamorph of the moss parasites may be instrumental in our understanding of the origin and evolution of the rust uredinial stage.

Aspergillus niger and A. nidulans were grown separately in glucose-limited chemostat cultures on modified Vogel's medium. Periodic selection (the appearance of new mutant populations) in A. niger was determined by monitoring oscillations in the concentration of cycloheximide-resistant mycelial fragments in samples from the fermenter vessel. Using these data, the interval between the periodic selection of each new mutant population was 32±6 generations (mean±S.E.M.). Periodic selection in cycloheximide resistance in three morphologically distinct sub-populations of the A. niger culture averaged 36±2, 31±11 and 28±5 generations and these values were not significantly different from that of the whole population (32±6 generations). Also, it was possible to estimate the rate of evolution taking place in these cultures by monitoring oscillations in the frequency of morphological mutants. The intervals between the periodic selection of morphological mutant populations in A. niger and A. nidulans were 28±3 and 22±2 generations respectively.

Eleven new species of the ascomycete genus Mycosphaerella from Queensland, Australia, are described, illustrated and where necessary compared with closely related members recorded in the same host family. The new species described are: M. cuttsiae, M. cyperi, M. dodonaeae, M. glochidionis, M. khayae, M. melaleucoides, M. morindaeM. platylobii, M. queenslandica, M. wollemiae, and M. xylomeli. With the exception of M. queenslandica, which is found on Dianella, all of the other species occur on host genera indicated by the specific epithet of the fungus. Apart from M. cyperi, the other species are all associated with necrotic leaf spots. Additionally, Sphaerella escalloniae is transferred to Mycosphaerella as M. escalloniae comb. nov., and M. aequatoriensis and M. pericampyli are newly reported from Australia.

A morphological study of Mexican collections of Crepidotus cinnabarinus, C. croceitinctus, C. palmarum and C. quitensis is provided. The relationships of these species with close allies are examined and discussed. Microscopical observations on the type collections of C. carpaticus, C. cinnabarinus, C. croceitinctus, C. luridus vars luridus, minor and oaxacae, C. macedonicus, C. palmarumm, C. quitensis, C. subcroceitinctus and C. unicus are included. Illustrations of the microscopic features of all taxa are presented.

Three new species of smut fungi (Ustilaginales) on grasses from Western Australia are described and illustrated: Sporisorium ordense sp. nov. on Brachiaria pubigera, Sporisorium paraneurachnes sp. nov. on Paraneurachne muelleri and Ustilago xerochloae sp. nov. on Xerochloa imberbis and X. laniflora. Smut fungi new to Australia are: Sporisorium heteropogonicola comb. nov. (based on Sorosporium heteropogonicola) on Heteropogon contortus, Sporisorium iseilamatis on Iseilema vaginiflorum (matrix nova), Tilletia opaca on Spinifex longifolius (matrix nova), Ustilago spermophora on Sporobolus australasicus (matrix nova). Sporisorium mitchellii, known hitherto from South Australia on Iseilema mitchellii, was collected on Iseilema dolicotrichum (matrix nova).

During an investigation of mycoparasitic fungi on sclerotia of Sclerotinia sclerotiorum in China, a new fungal species was consistently encountered and isolated from natural soils taken from soybean fields of Shandong and Jiangsu Provinces. The fungus is featured by its sphaeroid conidia with 1–2 transverse septa, but mostly (>65%) with only one septum at the base. It resembles Monacrosporium indicum, M. sphaeroides and M. sinense, but can be distinguished from the first two species by lack of basal hila and large vacuoles on its conidia, respectively, and from M. sinense by its typically two-celled and broadly turbinate to napiform conidia. Colonization frequencies on S. sclerotiorum sclerotia by the new species were 10% and 33.3% in the two field soils, respectively, when the sclerotia were introduced into soils and coincubated at 22–24 °C for 4 wk. Reinoculation tests by placing surface-sterilized sclerotia onto the tested isolate colony for 2 wk and then surface-sterilized again resulted in 23.3% sclerotia colonized. Microscopic observations indicated that the fungus coiled around hyphae of Rhizoctonia solani and grew along and appressed to hyphae of Fusarium solani f.sp. pisi, S. sclerotiorum and Phytophthora cactorum when dual-cultured in slides. Tests on agar plates demonstrated that the fungus formed adhesive networks and was an active predator of Panagrellus redivivus. This study indicated the diverse mechanisms for the fungus to survive in soil. For expression of its mycoparasitic and nematode-trapping capacities, the fungus is named as Monacrosporium janus.

A dikaryotic resting spore or two monokaryotic resting spores of Plasmodiophora brassicae were inoculated onto 1-d-old seedlings of Brassica campestris. The relative DNA content of a nucleus in a dikaryotic resting spore corresponded with that of a haploid nucleus in a monokaryotic resting spore. Plasmodia and zoosporangia were observed within the galls in some root cortical cells approximately 2 mo after inoculation. Resting spores were also formed within the galls in some cortical cells, and root hair infection was observed. The frequency of resting spore formation in B. campestris seedlings inoculated with a dikaryotic resting spore or two monokaryotic resting spores was 26·2 and 3·6%, respectively. The results indicate that the life-cycle of P. brassicae was completed on plants infected with a dikaryotic resting spore or by two monokaryotic resting spores.

Enridescalsia gen. nov., characterized by synchronous, polytretic conidiogenous cells and brown euseptate conidia, is described and illustrated from submerged, decaying leaves of Terminalia cattapa from Cuba. Notes on similar genera are given.

This issue of Mycological Research News features: Sudden oak death: Phytophthora ramorum exhibits transatlantic differences; and Cordyceps sinensis and Ganoderma lucidum amongst top ‘herbal’ medicines. An obituary of John Calhoun (1913–2002) is also included.

Papers in this part report on fungicide-resistant genes in Beaveria bassiana, and the transformation of Coniothyrium minitans. Molecular phlylogenetic studies reveal additional species in the Phytophthora gonapodyides–P. megasperma complex, establish the identities of Armillaria species in Zimbabwe, and analyze Didymella bryoniae isolates worldwide. Conditions affecting indole-3-acetic acid production in Lentinus sojar-caju have also been explored.

Endophytes reduce the density of rust pustules of Puccinia recondita f. sp. tritici in wheat. Thinning of Scots pine stands is shown to have little effect on the ectomycorrhizal species fruiting over 16 yr, and the strategies adopted by two Armillaria species in Norway spruce stump colonization have been compared.

Molecular data justifies the recognition of a new family and previously little-known generic name in Mucorales for the Mortierella isabellina group. Several new species of Mycosphaerella are reported on from Eucalyptus in Australia, and of Anthostomella on fynbos vegetation in South Africa. A new Lewia with an Alternaria anamorph on wheat in Norway has also been found.

The following new scientific names are introduced in this part: Umbelopsidaceae fam. nov.; Anthostomella brabeji, A. cynaroides, A. leucosperma, A. proteae, Lewia avenicola, Mycosphaerella ambiphylla, and M. aurantia spp. nov.; Umbelopsis autotrophica (syn. Mortierella ramanniana var. autotrophica), U. isabellina (syn. Mortierella isabellina), and U. ramanniana (syn. Mucor ramannianus) combs. nov.

Penetration of Monosporascus cannonballus into and growth within cantaloupe roots was studied using light and electron microcopy. Germ tubes penetrated the epidermis, and hyphae grew, without branching, almost directly to the xylem. The hyphae traversed the endodermis into protoxylem cells, and then grew extensively within the lumen of metaxylem vessels. Eventually, the hyphae grew back out into the cortical cells. A relatively low percentage of cells within both the cortex and xylem of lesions contained hyphae. The hyphae were generally localized within the lesion and could rarely be isolated more than 2 mm away from the margin of the lesion. Regardless of tissue type, hyphae were predominately intracellular. M. cannonballus appeared to be most similar to vascular wilt pathogens in its mode of parasitism, but does not spread via the vascular system to above-ground plant tissues.

The parenthesome structure of seven corticioid species, traditionally referred to the family Corticiaceae (Basidiomycota), were studied in order to better understand their taxonomic position: Phanerochaete velutina, Phlebia radiata, P. rufa, Rhizochaete americana (syn. Ceraceomyces americana), R. brunnea, R. filamentosa (syn. Phanerochaete filamentosa) and R. radicata (syn. Phanerochaete radicata). All possessed the perforate type of parenthesome that is commonly encountered in homobasidiomycetes. This feature excludes the above taxa from both the hymenochaetoid and the cantharelloid clades which are the only groups that have imperforate parenthesomes in the homobasidiomycetes.

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.

This report describes tests with Evan's Blue and MTT (3-[4, 5-dimethyl-2-thiazolyl]-2, 5-diphenyl-2H-tetrazolium bromide) for the assessment of the viability of rhinosporidial endospores. MTT stained a proportion of the spherical bodies that we regard as the Electron Dense Bodies (EDBs), and the cytoplasm of freshly prepared endospores or ones that were stored at 4 °. Slow-freezing at −20 °C, exposure to 10% formalin, or 0.1% sodium azide of the endospores abolished MTT-staining in both sites. Evan's Blue stained the EDBs and cytoplasm of fresh endospores or those stored at 4 °, and of sodium azide-treated or frozen (−20 °)-thawed endospores. TMRE (tetramethyl-rhodamine ethyl ester) specifically labelled the spherical bodies, supporting the conclusion that these spherical bodies have a mitochondrial-like structure. TMRE-staining was however retained in endospores after their treatment with formalin, sodium azide and slow-freezing while MTT-staining was abolished in all these treated endospores.

These results indicate that EvB and TMRE were capable of revealing the morphological integrity of endospores but failed to identify the metabolic inactivation of the endospores after treatment with formalin, sodium azide or slow-freezing. Only MTT was capable of identifying metabolically active endospores and hence their viability and could prove to be of value in standardizing models of infection.