Die natürliche Astreinigung und ihre biologischen Voraussetzungen

Placement of Triblidiaceae in Rhytismatales and comments on unique ascospore morphologies in Leotiomycetes (Fungi, Ascomycota)

Triblidiaceae is a family of uncommonly encountered, non-lichenized discomycetes. A recent classification circumscribed the family to include Triblidium (4 spp. and 1 subsp.), Huangshania (2 spp.) and Pseudographis (2 spp. and 1 var.). The apothecia of these fungi are persistent and drought-tolerant; they possess stromatic, highly melanized covering layers that open and close with fluctuations of humidity. Triblidialean fungi occur primarily on the bark of Quercus, Pinaceae and Ericaceae, presumably as saprobes. Though the type species of Huangshania is from China, these fungi are mostly known from collections originating from Western Hemisphere temperate and boreal forests. The higher-rank classification of triblidialean fungi has been in flux due in part to an overemphasis on ascospore morphology. Muriform ascospores are observed in species of Triblidium and in Pseudographiselatina. An intense, dark blue/purple ascospore wall reaction in iodine-based reagents is observed in species of Pseudographis. These morphologies have led, in part, to these genera being shuffled among unrelated taxa in Hysteriaceae (Dothideomycetes, Hysteriales) and Graphidaceae (Lecanoromycetes, Ostropales). Triblidiaceae has been placed within the monofamilial order Triblidiales (affinity Lecanoromycetes). Here, we demonstrate with a three-gene phylogenetic approach that triblidialean fungi are related to taxa in Rhytismatales (Leotiomycetes). We synonymize Triblidiales under Rhytismatales and emend Triblidiaceae to include Triblidium and Huangshania, with Pseudographis placed within Rhytismataceae. A history of Triblidiaceae is provided along with a description of the emended family. We discuss how the inclusion of triblidialean fungi in Rhytismatales brings some rarely observed or even unique ascospore morphologies to the order and to Leotiomycetes.

Influence of small scale conditions on the diversity of wood decay fungi in a temperate, mixed deciduous forest canopy

Studies on fungal richness and ecology have been largely disregarded since the first intensive efforts to investigate organismal diversity in forest canopies. We used the Leipzig Canopy Crane research facility to sample wood-decaying fungi in a mixed deciduous forest canopy 10-30 m in height. The structural complexity of the canopy was analysed using different methods, including meteorological measurements. With respect to temperature and relative humidity, marked differences existed between forest floor and upper canopy layers that persisted on smaller scales. Of the 118 taxa found in 128 sample units, pyrenomycetes and corticioid fungi outnumbered other macrofungal groups. Fungal communities showed distinct variations both in species richness and composition with respect to substrate (tree species), height in the canopy, stage of decay, and branch diameter. Pyrenomycetes and their anamorphs dominated the mycobiota on thin, exposed twigs at great heights, indicating their ability to overcome extended periods of drought and high levels of solar irradiance. Other taxa of Tremellales (Exidia spp.), Orbiliales (Hyalorbilia inflatula, Orbilia spp.) or Agaricales (Episphaeria fraxinicola, Cyphellopsis anomala, Lachnella spp.) also exhibited features that enabled them to develop in lesser protected habitats within tree crowns.

Two new species of Phialocephala occurring on Picea and Alnus

Two new species of Phialocephala were isolated from the periderm of living branches of forest trees in Germany. In culture, Phialocephala compacta Kowalski & Kehr sp.nov., found on Alnus, is characterized by crowded conidiogenous heads that become deeply pigmented with age. Phialocephala scopiformis Kowalski & Kehr sp.nov., isolated from Picea and other conifers, develops elongated, complex conidiogenous heads with up to 15 series of branches in culture. The taxonomic placement of both new species and their role in endophytism and in natural pruning of branches is discussed. Key words: Picea abies, Alnus glutinosa, Phialocephala compacta, Phialocephala scopiformis, branch pruning fungi.