Fungal endophytes inhabit healthy tissues of all terrestrial taxa studied to date; however, fungi associated with woody tissue have been frequently overlooked. Here, we examined endophytes associated with healthy living stems of tree species exotic to Argentina (Broussonetia papyrifera, Celtis occidentalis and Ligustrum lucidum) in a natural reserve. To achieve this objective, fungi were induced to develop within the wood by drying sections of branches. For comparison purposes, a study of the organisms present on superficial and inner bark was carried out. Fifty-seven strains belonging to 12 different taxa, dominated by the anamorphic states of ascomycetes, were obtained from the 180 cultured chips. Coprinellus micaceus, Lecythophora hoffmannii and Rhizopus microsporus are cited for the first time as endophytes. Only two taxa appeared on more than one tree species. Assemblages of fungi obtained from each tree species were different and the fungal endophytes isolated were very different from those previously recorded for leaves of the same hosts in the same area. Thus, it is probable that the endophytes exhibit host- and tissue-specificity. Considering three main factors: 1. the invasive nature of two of the selected hosts, 2. the evaluation of woody tissue and 3. the taxonomic identity of the fungal isolations, hypotheses concerning ecological implications are here discussed. In this sense, Broussonetia papyrifera and Ligustrum lucidum could be considered as sources of potential inoculum for native plants, especially in protected areas, and the high diversity of fungal species living within the tissues of the hosts studied suggests their potential as important fungal reservoirs to be taken into account in conservation issues.

Phylogenetic relationships of 12 species in Aleurodiscus sensu lato (Stereaceae, Russulales) described from the Patagonian forests of Chile and Argentina were investigated based on sequences of nuc rDNA internal transcribed spacer region ITS1-5.8S-ITS2 (ITS) and the D1–D2 domains of nuc 28S rDNA (28S). A new genus and a new species are presented, and 10 new combinations proposed. The genus Gloeosoma is shown to be phylogenetically well supported and morphologically circumscribed; it includes G. vitellinum (type species), G. mirabile, comb. nov., G. zealandicum, comb. nov., and Gloeosoma decorticans, sp. nov., which is newly described from Chile. The new genus Stereodiscus is proposed to accommodate a group of taxa characterized by an austral distribution and morphologically by smooth, thin-walled, amyloid basidiospores and a lack of gloeocystidia and acanthocystidia; three species develop Stereum-like basidiomata and two species present discoid ones. The new genus includes the species formerly known as Aleurodiscus antarcticus, A. limonisporus, A. parmuliformis, A. patagonicus, and A. triviale. Specimens of Stereodiscus parmuliformis (A. parmuliformis) from New Zealand (where it was originally described) and southern Chile are shown to be phylogenetically conspecific, which confirms its presence in Patagonia. Gloeosoma and Stereodiscus are shown to be distantly related to Aleurodiscus s. str. and other genera in Stereaceae. The new combinations Aleurocystidiellum bernicchiae, Aleurocystidiellum hallenbergii, and Acanthobasidium quilae are proposed based on morphology and phylogenetic analyses, and Aleurodiscus cerussatus is shown to be a cryptic species complex.