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In temperate systems of the Northern Hemisphere, wood‐decay fungi are known to facilitate cavity excavation by woodpeckers. For South America, woodpecker–fungi interactions have not been explored. The aim of this work was to identify wood‐decay fungi associated with the process of cavity excavation by the Magellanic woodpecker (Campephilus magellanicus), a large South American picid that excavates on living trees. The survey was conducted in old‐growth Nothofagus pumilio forests of Patagonia. For freshly excavated cavities, wood condition was assessed, adjacent basidiocarps were collected, and fungal cultures were obtained from wood samples taken to the laboratory. All cavities exhibited softened wood. Four Agaricomycotina were isolated in cultures: Stereum hirsutum was the most frequent, followed by Postia pelliculosa, Nothophellinus andinopatagonicus and Aurantiporus albidus. Basidiocarps around cavities were of two species that did not develop in cultures: Laetiporusportentosus and Macrohyporia dictyopora. Excavations were slightly more frequent in white rot colonized than brown rot colonized wood, but this may be an artefact of differential success in fungal isolation and culturing, since several cavities that showed visual symptoms of brown wood rots did not yield mycelia of those wood‐decay fungi. As shown by research elsewhere, basidiocarps underestimated heart rot on cavity walls and revealed additional wood‐decay species living on the same trees; therefore, assessments of fungal diversity in substrates used for cavity excavation should be based on culturing and/or DNA extraction. Because fungal communities in the southern Andes are poorly known, decay fungi and their roles in ecosystem development should be studied across different forest areas, where samples from non‐cavity‐bearing (control) trees should also be taken in order to determine excavation‐site selection. [ABSTRACT FROM AUTHOR]

Six poroid Hymenochaetaceae from Patagonia, Argentina, were studied phylogenetically with nuc rDNA internal transcribed spacer (ITS) and partial 28S rDNA sequences, together with morphological data. Two new genera and a new species are introduced as well as two new combinations proposed. Arambarria destruens gen. et sp. nov. is proposed for a taxon fruiting on fallen or standing, dead Diostea juncea and Lomatia hirsuta and previously recorded erroneously as Inocutis jamaicensis; it is distinguished by annual, effused to effused-reflexed basidiomes forming pilei, a monomitic hyphal system, thick-walled and yellowish basidiospores (brownish chestnut in potassium hydroxide solution), lack of a granular core in the context and lack of setoid elements. Nothophellinus gen. nov. is proposed to accommodate Phellinus andinopatagonicus, the main white wood-rotting polypore of standing Nothofagus pumilio and also an important wood-decayer of other Nothofagus species from southern Argentina and Chile. It is morphologically similar to Phellopilus (type species P. nigrolimitatus) but differs by lacking setae. The new combinations Pseudoinonotus crustosus and Phellinopsis andina are proposed for Inonotus crustosus and Phellinus andinus, respectively. Phellinus livescens, which decays the sapwood of several standing Nothofagus species, is closely related to Phellinus uncisetus, a Neotropical species related to Fomitiporia; for the time being P. livescens is retained in Phellinus sensu lato. An unidentified taxon responsible for a white heart-rot in living Austrocedrus chilensis grouped with Phellinus caryophyllii and Fulvifomes inermis, but its generic affinities remain ambiguous. Transmission electron microscopy studies confirm this unidentified taxon has an imperforate parenthesome, which is typical of the Hymenochaetaceae. [ABSTRACT FROM AUTHOR]