579 Mikroorganismen, Pilze, Algen
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Erysiphe platani
(2012)
This work deals in two sections with the North American plane powdery mildew Erysiphe platani, an epidemiological study and a molecular phylogenetic analysis based on rDNA ITS sequence data. Most likely, the species was introduced in South Europe at the beginning of the 1960s. In 2007, it was observed for the frst time in Germany near Freiburg (SW Germany) and obviously did not reach other German states until 2009. A detailed monitoring from 2009 to 2011 shows that the fungus continually spread north- and northeastward with a speed of roughly 190 km/year. The northernmost record is from Arendsee in the north of Sachsen-Anhalt from 2011. We assume that the species has come from the Rhone valley and the Burgundian Gate fnally entering Germany in the Upper Rhine plain. The molecular phylogenetic analyses of material of different geographic origins indicate that specimens from Germany and Italy are identical, differ slightly from those from Greece and strongly from extraeuropean (Australia, USA) material. This might indicate a considerable rate of mutation of this powdery mildew with North American origin in the new European area. In addition, the phylogenetic analyses confrm that E. platani is related to other tree-inhabiting powdery mildew species previously accommodated in the genus Microsphaera.
The new genus and species Deltopyxis triangulispora is described. It is so far known from 14 sites in the south of Luxembourg and one in the neighbouring region of France. The discomycete forms very small, blackish-brown apothecia on bark, more rarely on wood, but particularly on more or less strongly senescent hymenia of Vuilleminia spp. The apothecia occur on dead, corticated, internally very slightly to rather strongly white-rotten, attached or broken, periodically dry branches at a height of about 1–3 m above ground. In most of the collections Vuilleminia was present and covered the
bast on one side of the branch, while the periderm still covered the remaining areas. D. triangulispora is so far recorded on angiosperm shrubs of the genera Corylus, Crataegus, Ilex, Prunus, and Salix, which had an advanced age or were already dead. The species prefers undisturbed, usually thermophilous hedges or open woodlands, especially close to their edges, but sometimes occurs also in dense, more air-humid woods. The fungus is characterized by 64-spored, elongate saccate, short-stalked, inamyloid, rather thin-walled asci which arise from croziers and open at the apex by a broad slit-like pore. The hyaline ascospores have a distinctly triangular shape when seen in profile view, but look slightly flattened, (ellipsoid-)deltoid in front view. In the living ascus they are arranged in a dense elongate cluster, which is forcibly discharged as one entity.
The position of Deltopyxis within the Ascomycota is unknown.
In the upper Danube river-system, but also in some more watercourses of the German lower mountains range, an endolithic filamentous cyanobacterium is a prominent compound of the phytobenthos. These filaments penetrate limestones in the river bed and form brush-like endolithic layers of about 0.5 mm in depth. There are similarities between this taxon and approximately 10 other filamentous Cyanophyceae in terms of the width of the trichomes, the geometry of the cells and the shape of the apical cells. However, none of these species allow for a direct and clear-cut identification, and a precise taxonomic determination has therefore been unresolved until today. In order to make progress in this matter, it is necessary to get a better insight into the boring behaviour of this inhabitant and into the endolithic arrangements of the filaments. For
this purpose, special preparation methods and SEM examinations were applied. The results of these procedures as well as critical comparisons with taxonomic properties of similar phormidian taxa, and the special demands on physico-chemical water conditions, led to the conclusion that the taxon in question cannot be assigned to a known species, but must be considered as an independant species. It is here described as Phormidium ingrediens species nova.
We report the unexpected discovery of foliicolous lichen communities at several localities in the Black Forest, south-western Germany, with a total of seven truly or facultatively foliicolous taxa: Bacidina chloroticula, Fellhanera bouteillei, F. subtilis, F. viridisorediata, Fellhaneropsis myrtillicola, Gyalectidium setiferum, and Scoliciosporum curvatum. The communities are similar to those reported previously from Belgium, western Germany (Mosel valley), and Austria (Styria), apparently forming a characteristic association across central Europe (Fellhaneretum myrtillicolae SPIER & APTROOT), but are richer in species in the Black Forest than in any of the other areas studied. An identification key is provided to the species of this association in the Black Forest. Gyalectidium setiferum is new for central Europe, and Scoliciosporum curvatum is new to southern Germany.
Since these lichen communities appear to be confined to well-conserved forest and depend on favorable, warm-humid climatic conditions, their potential use as indicators of global climatic change is discussed.
The morphology of the anamorphic hornbeam powdery mildew fungus Oidium carpini on Carpinus betulus is re-examined using light microscopy. All morphological features were documented by line drawings The conidiophore length is very variable and depends on which side of the leaf the conidiophores are formed. This variability is discussed with respect to the morpho-taxonomic value of conidiophore length and identification of anamorphic Erysiphales species. Furthermore, we report this species for the first time from Iran.
Lecanora panis-erucae HERTEL & V. WIRTH, a lichen almost exclusively grazed by the larvae of an unidentified moth, is described as a new species. Lecanora substylosa (losa (losa ZAHLBR.) HERTEl & V. WIRTH comb. nova (basionym:
Lecidea substylosa NYL.), a relative of Lecanora sulphurella HEPP differing by its chemistry, hitherto known only from its type collection, is reported from numerous localities. Lecidella placodina (Lecidella placodina (Lecidella placodina NYL.) HERTEL, previously known only from its type locality in the Angolan part of the Namib Desert, is reported from other localities in
Namibia. Lecidea quartzina STIZ., judged to be a close relative of L. tragorum ZAHLBR., and hitherto known only from its type locality in the Cape Province of South Africa, is reported as new to Namibia. Lecidea sarcogynoides, also hitherto unrecorded for Namibia is reported from a number of localities.