A new nematophagous hyphomycete is described from the Canary Islands as Arthrobotrys hertziana. It has branched conidiophores with slightly swollen tips, mostly three-septate conidia, and sticky knobs as trapping devices. A key to Arthrobotrys species forming sticky knobs is presented. Among six nematode and two springtail species tested as hosts only the nematode Panagrellus redivivus was trapped. The results are discussed with reference to taxonomical problems and the possibly limited host range.

When isolate NIOI of self-inducing Phytophthora boehmeriae was grown on medium containing the fungicide ethazol, the fungus produced oospore-free sectors from which self-sterile cultures were recovered. Self-sterile cultures were also recovered from three of six other isolates tested. Single hyphal fragment cultures and single zoospore cultures derived from these self-sterile cultures were of A1A2, A1, A2, and A0 types. Conversion of self-fertile species of Phytophthora to A1 and A2 types is suggested as another possible evolutionary origin of the two sexes in lower organisms, in addition to previously reported mating type change as a possible origin of sexes.

Dactylella huisuniana sp. nov., is described and illustrated from decaying leaves. It is characterized by tall, simple, erect, hyaline, septate conidiophores which bear denticulate, terminal or subterminal to lateral conidiogenous cells. The conidiogenous cells elongate and elaborate and become somewhat geniculate or candelabrelloid in age. The conidia are predominantly fusoid, 3-septate, widest at the distal second cell. The organism traps nematodes by adhesive knobs at the apex of erect, flexuous, unicellular pedicels arising from hyphae. The differences between D. huisuniana and D. arcuata, D. asthenopaga, D. drechsleri, D. ellipsospora, D. lysipaga, D. multiformis, Dactylaria candida, D. haptotyla, and D. sclerohypha are briefly discussed.

Gaeumannomyces graminis var. tritici is the aetiologic agent of take-all disease of wheat and barley. Heavily-melanized variants of a lightly pigmented, virulent wild-type strain were isolated and characterized. These variants were phenotypically similar to Phialophora sp., the proposed anamorph of Gaeumannomyces graminis var. tritici. Unlike the wild-type G. graminis strain, Phialophora-like variants produced conidia and lost their ability to reproduce sexually after serial transfer. Some ascospores from initial self-crosses of the Phialophora-like variants regained the G. graminis phenotype, and these derivatives could again produce Phialophora-like variants. As with Phialophora isolates from the field, Phialophora-like variants produced in this study were non-pathogenic and produced less extracellular protein.

Muskmelon crops have sustained serious losses in Spain since 1980, due to a disease characterized by a sudden collapse of the plant as the fruit approaches maturity. The cause has been attributed to Acremonium cucurbitacearum. To evaluate the genetic variation of A. cucurbitacearum in Spain and its relationship with other species of Acremonium, a study of vegetative compatibility groups (VCGs) and random amplified polymorphic DNA (RAPD-PCR) was carried out on 29 isolates from diseased muskmelon plants. The species used in comparison with A. cucurbitacearum were A. charticola, A. strictum, A. kiliense, A. sclerotigenum and A. crotocinigenum. Spanish isolates of A. cucurbitacearum were grouped in eight different VCGs, with two isolates belonging to more than one VCG. In only two of the reference species was it possible to complete all of the complementation tests: A. charticola (VCG 100) and A. crotocinigenum (VCG 200). The isolates of A. sclerotigenum and A. kiliense appeared to be naturally resistant to chlorate and could not be tested for VCG. All strains of A. strictum assayed were heterokaryon self-incompatible. The RAPD data showed considerable genetic variation, with 14 isolates grouped in 11 haplotypes. They also supported the recognition of A. cucurbitacearum as a new species, as the genetic similarity between A. cucurbitacearum and the reference species was less than 0·05.

Anthostomella petrinensis and A. theobromina are described from endemic Pandanus species in Mauritius. They are compared with other Anthostomella species reported on Pandanaceae and Palmae. A table is included, facilitating comparison between the new species and previously published taxa with similarly sized ascospores.

Four rare microfungi, Dactylaria appendiculata, Exserohilum novae-zelandiae, Monacrosporium psychrophilum and Pleurocatena acicularis, were found when root pieces taken from wheat crops were incubated on low nutrient agar (SNA).

Germinating spore-balls of Urocystis hypoxis produce both unicellular basidia, crowned with 4–6 basidiospores, and what appear to be transversely septate, 3-celled, prostrate basidia with conjugation, through a conjugation tube, between top and bottom cells. This most unusual situation is discussed in relation to the taxonomy of smut fungi.

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.

Rotiferophthora ellipsospora and R. japonica spp. nov., are described as endoparasites of bdelloid rotifers, forming large dictyochlamydospores and small infection conidia. Verticillium bactrosporum was found in association with a new host species of bdelloid rotifer and was cultured for the first time: resting spores were formed in culture.

The characterization of type cultures of the S. thermophilum complex remains unclear and morphological features have been relied upon to recognize such isolates. The aim of this study was to compare morphological and thermal methods, in order to identify relationships between cell wall and cultural characteristics. The differences in the proportions of structural and non-structural fractions and the peak decomposition temperatures of the test isolates were significant. The thermograms produced can be grouped into two distinct types, which can be further sub-divided, in agreement with microscopic classification. The relationship between the various morphological parameters including extension rate, sporulation, microscopic type and DTG parameters are discussed briefly.

This issue of Mycological Research News features: Confusion over Amanita pantherina in Japan; Foliicolous lichens are benign; A plethora of bryophilous niches; and A longevity gene in Saccharomyces.

Fast-tracked for publication in this issue is the description of another new species of pathogenic Phytophthora, attacking deciduous trees in Europe. Specific primers for the detection of Pythium oligandrum in mushroom beds have been developed and tested. Puccinia tanaceti is shown to be more host-restricted than supposed. Transformation systems for Venturia inaequalis are compared, and the separation of Fusarium species causing crown and head blight of cereals, and also of Vericillium dahliae and V. tricorpus is described.

The genetic basis of Aspergillus parasiticus strains that do not form aflatoxins has been explored, and large insert had been found in an aflatoxin-producing A. flavus strain. Two genes involved in the early stage of melanin production in Colletotrichum lagenarium are reported, and pairing tests in Helocobasidium mompa show it to have a single incompatability factor. Strategies adopted for growth in toxic metal environments have been studied and factors affecting growth determined. Conditions to optimise growth in entomophthoralean fungi have been explored, the coffee berry borer in Mexico has been found to support a wider range of fungi than hitherto expected, and a new Monacrosporium able to trap nematodes as well as to parasitize fungal sclerotia has been discovered.

The following new scientific names are introduced in this part: Monacrosporium janus, and Phytophthora pseudosyringiae spp. nov.

Minimidochium parvum sp. nov. is described from floating litter collected in polluted water from the Rio Santiago.

Podosphaera clandestina var. cydonia var. nov., Setoerysiphe kashmiriensis sp. nov. and Brasiliomyces kumaonensis sp. nov., collected from Northern India on Cydonia oblonga, Sambucus wightiana and Quercus sp., respectively, are described and illustrated.

The ontogeny of the fruit bodies of Mycena stylobates was studied by light microscopy and scanning electron microscopy (SEM). The ontogeny was divided into two phases: first the primordium with all the structures of the mature fruit body was established, then the primordial stipe elongated rapidly and the exposed hymenium started producing spores immediately. The first detected stage of fruit body formation was an irregularly arranged hyphal structure within the substrate colonized. After the rupture of the surface of the substrate, the primordium established on the surface. Soon a layer of wrapping hyphae was differentiated, which covered the complete primordium. The structures of the stipe and the cap developed synchronously. The developing stipe, cap and basal disc together formed a secondary ring-like cavity, in which the development of the hymenophore took place. The lower side of the cap was covered by a layer of degenerated hyphae. The development of the hymenophore started with a number of small alveolae on the lower side of the cap, which were covered with a hymenophoral palisade. The margins of these alveolae formed the primary lamellae, which in the first stage of their development were covered by a layer of degenerated hyphae. The hymenophoral palisade spread from the developing alveolae to the lamellar edge; the edge of the primary lamellae was forked in the early stages. Secondary lamellae were formed by the down folding of ridges from the lower side of the cap. In contrast to the primary lamellae, they were covered with hymenophoral palisade from the beginning. Spore production started immediately after the elongation of the stipe. These results were compared with other known modes of ontogeny within the Agaricales and some comments on the terminology used for the description of basidiome morphogenesis are made.

Three species of Phaeoramularia, P. indica sp. nov., P. moracearum sp. nov. and P. psidii-guajavae sp. nov. on Acalypha indica, Ficus religiosa and Psidium guajava, respectively, are described and illustrated from material collected in Gorakhpur and the adjoining area.

Ancorasporella mexicana gen. et sp. nov., collected on the dead leaf stalk of an unidentified fern in a cloud forest in the state of Veracruz, México, is described and illustrated. This singular hyphomycete is distinguished from known genera by its euseptate, triangular or fusiform conidia which are attached at 90° to the long axis of the cicatrized conidiogenous cell.

A new nematophagous-predacious hyphomycete, Candelabrella shahriari sp. nov., which captures nematodes by means of adhesive networks, is described and illustrated.