A method for visualization of fungal nuclear structures using the DNA specific fluorochrome SYTOX Green and confocal laser scanning microscopy is presented. The staining procedure detects nuclei in different cell types with high contrast. Furthermore, the method permits generation of high-resolution confocal image stacks using optimised scanning conditions. This approach significantly improved visualization of stained fungal nuclear structures. The technique was applied to some lichenized fungi, but can also be used to study similar detail in non-lichenized fungi. In certain cases, incompletely separated chromosome-like structures, heterochromatic material as well as weakly stained nucleolar regions can be seen. In Xanthoria parietina, variation in the nuclear division was observed in developing ascospores. Delayed division after the formation of endospore thickening resulted in the exchange of nuclear material through a narrow isthmus.

Diplocladium gregarium was described almost one hundred years ago, later transferred to Cylindrocladium, and finally excluded from this genus. It has recently been rediscovered from bark beetle galleries in the bark of Picea abies and Pinus sylvestris in Germany. The fungus is redescribed and a new genus is proposed to accommodate it.

Dictyoporthe cinnamomi sp. nov., Pseudomassaria cyclobalanopsidis sp. nov. and Splanchnonema verruculospora sp. nov. are described and illustrated from Taiwan and compared with closely related species. A key to species of Dictyoporthe is also provided.

The fungus first described as Lentinus flabelliformis var. herbarum has been found fruiting on dead Epilobium angustifolium stalks at La Chaise-Dieu (France), the first record since its original diagnosis. The basidiospore characters, trama and hymenium structure indicate the species belongs Lentinellus sect. Omphalodei (Hericiales), but the absence of clamps is a remarkable character, new for this genus. The new combination L. herbarum comb. nov. (syn. Lentinus flabelliformis var. herbarum) is made and a neotype designated. A key to the eight European taxa of sect. Omphalodei is included.

Pycnial nectar of one mating type is known to induce cap formation on pycniospores of opposite mating type within several species of Puccinia and Uromyces. To learn if caps are induced by nectar transfers between species, we used interspecific pairings involving six species of Puccinia and three of Uromyces. Overall, caps were induced in 14 pairings between different species involving all tested species, except Puccinia helianthi which has no intraspecific cap induction. Nectar (with pycniospores) exchanged in reciprocal transfers between individual pycnial clusters of two different species gave pycniospore caps in nine of 16 cluster pairings, comparable to rates within species. Spore-free nectar combined from five or more pycnial clusters of one species (to ensure that nectar of two mating types was present) usually induced caps in pycniospores from single pycnial clusters of a second species. This occurred in all tested pairings of species except pairings involving P. helianthi. In experiments with pycniospore-free nectar of one capping type specificity from P. recondita, caps were induced in about 50% of pycnial clusters of unknown capping type from P. triticina or P. hordei and only in pycnial clusters of one capping type from P. triticina or P. reichertii in experiments in which type within species was determined. Coupled with the fact that capping type specificity and mating types are coincident within species, the results indicate that mating type-specific induction of pycniospore caps by nectar extends across species boundaries. Although aecia were never produced in interspecific pairings, cap induction occurred as it does in intraspecific pairings where it precedes aecium formation in species exhibiting the capping phenomenon.

Four new species of Pseudocercospora are described, illustrated and compared with allied taxa. These are P. asiatica or Glochidion lanceolarum, P. melochiigena on Melochia corchorifolia, P. operculinae on Operculina terpethum and P. trewiae-nodiflorae on Trewia nodiflora.

Exserohilum longisporum sp. nov., isolated from Miscanthus sinensis, is described and illustrated. Its affinity to closely related species is discussed to show the distinguishing morphological features.

Ultrastructural and morphological studies have been carried out on M. tumidum, the type species of Myelosperma. Asci are provided with a distinctive refractive subapical ring, which differs from that found in other unitunicate families. The ascospores are reniform in all species and surrounded by mucilaginous sheaths of various shapes. Numerous ascomata also develop in a circle around a common central pore. At the ultrastructural level the ascus apex comprises an electron-transparent thickening incorporating a subapical electron-dense hemispherical ring-like structure and the ascus wall is continuous over the apex. This type of ring is compared with those found in representative species in other related families. Based on these observations, a new family, the Myelospermaceae, is introduced, to accommodate Myelosperma. The rationale behind this is discussed, and M. alata is described to accommodate a remarkable new species from the Seychelles. Arguments for the possible inclusion of Manokwaria, Palmicola and Pemphidium in the Myelospermaceae are given.

A cDNA encoding a chaperone ClpA homologue of Paracoccidioides brasiliensis was isolated and characterized. The ClpA belongs to a group of ClpATPAses proteins, which are highly conserved, and include several heat inducible molecular chaperones. In this study, a 2879 bp cDNA designated as Pbclpa was obtained which encodes a predicted protein of 927 amino acids. Characteristic consensus motifs of the ClpATPases family are present. The PbClpA middle region was compared to other related ClpA and ClpB proteins from fungi and bacteria. Comparative analysis demonstrated in the middle region the presence of a heptad repeat sequence, characteristic of ClpBs from prokaryotes and fungi, which are absent in ClpAs from prokaryotes but were present in all described fungal ClpAs. Our comparative analysis reveals that one of the criteria typically used to distinguish the prokaryotic subfamilies ClpA and ClpB, the size of the middle sequence, may not be useful in fungi. Phylogenetic analyses were performed with the complete sequences of ClpAs from fungi and bacteria and with the middle regions of those ClpAs present at NCBI and Pfam databases. Our results indicated that both types of analysis can be useful as a tool in the determination of phylogenetic relationships.

We studied the fungal colonization of Pinus sylvestris needles in two neighbouring sites, comparing stands of isolated and grouped trees. We observed large variations among the proportions of needles bearing fruit bodies of Cyclaneusma minus, Lophodermium pinastri, Verticicladium trifidum and black lines characteristic of L. pinastri colonization. Variations between sites and within trees were greater than that between stands or between trees. The frequency of L. pinastri colonization was negatively correlated with C. minus fruit body frequency, while the frequency of V. trifidum conidiophores was positively correlated with L. pinastri colonization frequency without fruiting, and negatively correlated with C. minus apothecia frequency. Although L. pinastri black lines and C. minus apothecia were nearly randomly associated on individual needles in each sample, the two fungi occupied different segments when they occupied the same needle. These patterns at needle and sample scales do not explain the negative correlation between the frequencies of these two species observed at larger scales. In each sample, frequency of V. trifidum conidiophores was highest on needles colonized by L. pinastri without fruiting. On individual needles, V. trifidum conidiophores developed on segments colonized by L. pinastri without fruiting, but not on segments bearing fruit bodies of L. pinastri or C. minus. These patterns at needle and sample scales were consistent with the correlations between frequencies observed at larger scales. These results were compared to variations observed with stand age and climate in others studies. The observed variations might result from both microclimate variations and fungal interactions.

Seven new species of smut fungi from the neotropics are described. The new species are remarkable for their special morphological development, as new representatives of small genera, or by interesting host plants and contribution to our knowledge of neotropic biodiversity. Aurantiosporium pallidum from Bolivia is the third species known in its genus. Its sori develop in the hypertrophied tissue of the rachillae of female and male spikelets. Kuntzeomyces ruizianae from Colombia is the second species known in its genus, characterized by relatively small teliospores. Moreaua bulbostylidis from Bolivia and Venezuela is the first record of a species of this genus (formerly Tolyposporium) on the genus Bulbostylis (Cyperaceae). Thecaphora amaranthicola from Ecuador differs from the known species T. amaranthi on the same host genus by smaller balls of teliospores. Thecaphora smallanthi is the first species of Thecaphora known to include hyaline globose sterile cells in the centre of teliospore balls. Tilletia boliviana is the first species of Tilletia infecting a species of Bromus (Poaceae) and forming warty teliospores. Species of Urocystis on Poaceae are known as agents of stripes on leaves, stems, and inflorescences. Urocystis reinhardii from Bolivia is the first species of this genus with sori in the interior of hypertrophic peduncles of a grass.

Lindtneria hydnoidea sp. nov. is described, characterized by a hydnoid hymenophore and a total lack of clamp-connections on the generative hyphae. A key is given to all currently accepted Lindtneria species.

Gyrothrix flagelliramosa, a new species of hyphomycete, found in litter floating in hydrocarbon-polluted water in the Santiago River, Argentina, is described and illustrated.

This is the first report demonstrating Amorphotheca resinae to be a natural member of the soil mycobiota in Germany. The fungus was detected at 19 out of 68 collection sites and was most frequently isolated from soil under or in the vicinity of yew trees (Taxus baccata). This finding is in contrast to reports from other countries, where no correlation was found between the presence of the fungus and the kind of soil or vegetation. A. resinae could not be re-isolated by standard methods like the soil dilution technique or the soil plate method, unless the fungus was present in high numbers of colony forming units. By a modification of the creosoted matchstick method it was possible to detect the fungus when as few as 11 viable spores were present in a plate with 20 g of soil.

Hemibeltrania saikawae sp. nov., found on decaying leaves in Cuba and characterized by cylindrical to clavate, mammillate, one-celled conidia, is described and illustrated. A key to Hemibeltrania species is provided.

A stalked, cyphelloid basidiomycete from Kenya described as Stipitocyphella keniensis gen. et sp. nov. is illustrated. Possible relationships of this species with other basidiomycetes are discussed. Phylogenetic processes during gill and basidioma formation are proposed.