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Three undescribed European species of Xylaria are recognized from new combinations of anamorphic and teleomorphic characters. Their phylogenetic affinities are revealed by a 5.8S/ITS nrDNA analysis. Two of them (X. karsticola and X. vasconica) appear closely related to X. hypoxylon sensu stricto. Xylaria cinerea is distributed in western Europe (France, Spain, United Kingdom) and the Canary Islands and appears closely related to a yet unnamed taxon from New Zealand. In addition to southwestern Europe, X. vasconica is also present in eastern USA. A specimen of X. hypoxylon from the US West Coast agreed with European material with regard to the teleomorph, but its cultures showed a different morphology. Xylaria arbuscula var. plenofissura is reported from a natural habitat on the European mainland for the first time, and the occurrence of this member of the X. arbuscula complex on the Canary Islands is confirmed.

The tropical genus Thamnomyces is characterized by having wiry, black, brittle stromata and early deliquescent asci, lacking an amyloid apical apparatus. Thamnomyces is regarded as a member of the Xylariaceae because the morphology of its ascospores and the anamorphic structures are typical for this family. However, its relationship to other xylariaceous genera remained to be clarified. Cultures of three Thamnomyces species were obtained and studied for morphological characters, and their secondary metabolite profiles as inferred from high performance liquid chromatography coupled with mass spectrometric and diode array detection (HPLC-MS/DAD) were also compared. Cultures of Thamnomyces closely resembled those of the genera Daldinia and Phylacia and even produced several secondary metabolite families that are known to be chemotaxonomic markers for the aforementioned genera. These findings were corroborated by a comparison of their 5.8S/ITS nrDNA sequences. We conclude that Thamnomyces, Daldinia, and Phylacia are derived from the same evolutionary lineage, despite these genera differing drastically in their stromatal morphology and anatomy. Along with Entonaema and Rhopalostoma, these fungi comprise an evolutionarily derived lineage of the hypoxyloid Xylariaceae. A new species of Thamnomyces is erected, and preliminary descriptions of three further, potentially new taxa are also provided.

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To gain an insight into fungal sooty mould communities on leaves of trees and shrubs in the tropics and in temperate regions, 47 biofilms of the Mata Atlântica rainforest relic and the Caatinga vegetation in the state of Sergipe, Northeast Brazil, and from Central European colline and alpine zones were compared. The four sampling sites clearly differed in composition of their epiphyllous fungal communities. The fungal OTUs from all sites belonged mainly to the Ascomycota, with Dothideomycetes being the dominant class. The core community group consisted of a few site-specific representatives in co-occurrence with the ubiquitous Mycosphaerella tassiana and Aureobasidium pullulans. Most species of the core community were dark pigmented and were accompanied by facultative unpigmented or lightly pigmented species. Among the cultivable fungal species, the proportion of melanised species was significantly more abundant in samples from the two European sites, which supports the theory of thermal melanism. The identity of the host plant had a stronger impact on fungal community composition than the presence of sap-feeding insects.

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In this study, relevant variables were determined to predict the probability of sooty mould biofilm (SMB) occurrence on willow leaves in a multivariate model. Despite a large temporal gap between the main sap-feeding insect (SFI) season in spring (May to June) and the main season of SMBs in late summer and fall (August to September), trees infested with SFIs on four or more observation dates had significantly more SMBs (3.7-fold) toward the end of the growing season. In addition, a horizontal leaf position and recessed leaf veins, traits that may increase the wettability of the leaves, positively influenced SMB occurrence (27.8-fold). Among the weather parameters, those that lead to higher moisture on leaf surfaces, namely high morning and evening relative humidity, higher precipitation sums, and lower vapour pressure deficit values, also had the strongest positive effect. In addition to these parameters, higher wind speeds also had a strong positive effect on SMB occurrence.