DOI: 10.5091/plecevo.128682

Authors: Alexander Ordynets, Gérald Gruhn

Abstract: Background and aims – During fieldwork in French Guiana in 2018, two fungal specimens resembling Subulicystidium oberwinkleri were collected. This study aims to clarify species- and genus-level assignment of this material and of S. oberwinkleri. Material and methods – Corticioid fruiting bodies were examined under a light microscope, and spores from the spore prints were studied morphometrically. DNA sequences of large subunit-coding DNA and internal transcribed spacer were used for maximum likelihood and Bayesian phylogenetic analyses. Furthermore, guanine-cytosine content was calculated for the LSU dataset, and UNITE Species Hypotheses Matching Analysis was performed for newly generated ITS sequences. Key results – The new genus, Palliocystidium, is introduced in the family Hydnodontaceae, based on the peculiar pattern of cystidial encrustation (crystalline plates of various shapes) and cystidial septation and supported by results of phylogenetic analyses. Within the new genus, the new species P. chlamydatum from French Guiana is described. In addition, Subulicystidium oberwinkleri is transferred to Palliocystidium. The two species can be distinguished by the size of their reniform spores. Both species display high levels of guanine-cytosine content at the scale of the order Trechisporales. Conclusions – In the newly introduced genus Palliocystidium and genera Subulicystidium and Luellia, there is significant potential for further exploration of species diversity and generic boundaries. Additional intensified fruiting-body-based sampling of taxa and genes is necessary to clarify the relationship of genera within Hydnodontaceae.

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DOI: 10.5091/plecevo.2021.1857

Authors: Viacheslav Spirin, Sergey Volobuev, Vera Malysheva, Otto Miettinen, Heikki Kotiranta, Karl-Henrik Larsson

Abstract: Background and aims – To date, Megalocystidium leucoxanthum, a corticioid fungus originally described from the Italian Alps, was considered as a widely distributed species inhabiting numerous angiosperm hosts in the northern hemisphere. Its specimens collected in different geographic areas and from various host species revealed a high morphological variability and thus obfuscated differences from the closely related M. luridum. The objective of this study was to re-establish M. leucoxanthum based on newly collected and sequenced specimens and clarify the identity of morphologically deviating collections previously ascribed to this species.Material and methods – In total, 87 specimens of Megalocystidium spp. (including two historical types) were studied by morphological methods. Their phylogenetic relations were investigated based on DNA sequences (nrITS, nrLSU, and tef1) of 29 specimens.Key results – Based on morphological, ecological and DNA data, we showed M. leucoxanthum sensu typi is a rare species restricted to Alnus alnobetula in subalpine and subarctic zones. Consequently, records from other hosts (mostly representatives of Salicaceae) belong to three other species, M. olens, M. perticatum, and M. salicis, described as new to science. The fourth newly introduced species, M. pellitum, occurs on the same host tree as M. leucoxanthum but it can be separated from the latter due to distinctive morphological traits and DNA sequences. Additionally, Aleurodiscus diffissus is combined in Megalocystidium and the identity of M. luridum is clarified.

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DOI: 10.5091/plecevo.2020.1667

Authors: Viviana Motato-Vásquez, Adriana Gugliotta, Mario Rajchenberg, Myriam Catania, Carlos Urcelay, Gerardo Robledo

Abstract: Background and aims – Bjerkandera is one of the few poroid genera in the Phanerochaetaceae family known to date. The genus has a worldwide distribution and is characterized by effused-reflexed, pileate basidiomata with a pale cream to smoky or mouse grey hymenophore that becomes darker when dried, and a monomitic hyphal structure with clamped generative hyphae. Morphological and phylogenetic studies have traditionally accepted only two species in the genus, B. adusta (generic type) and B. fumosa, both described from temperate Europe. Recently, three additional species, B. atroalba, B. centroamericana and B. mikrofumosa were described from the Neotropics. While studying polypores in the Yungas forests of northwest Argentina and the Atlantic Forest of southeast Brazil, several specimens of Bjerkandera were gathered. A comparative morphological study revealed that some of these specimens do not correspond to any of the known species in the genus. This study aimed to propose a broad species-level phylogenetic hypothesis for Bjerkandera in the Neotropics and worldwide and to discuss the taxonomic status and diversity of the species in this genus.Methods – This study is based on a morphological examination of specimens collected between 2012 and 2017, and on a revision of original collections, including the type specimens. A total of eleven ITS and seven nLSU sequences were generated and phylogenetic analyses based on Bayesian Inference (BI) and Maximum Likelihood (ML) were performed.Key results – An extensive documentation of the species diversity within Bjerkandera in the Neotropics is presented. Genetic data of B. mikrofumosa were obtained for the first time and its phylogenetic position was tested. Additionally, its geographic distribution was extended in the Neotropics to Argentina and Brazil. Finally, molecular and morphological evidence was used to propose a new species for the genus, Bjerkandera albocinerea sp. nov.Conclusion – This study provides an update of the known diversity of the genus in the Neotropics and worldwide. In addition, our results indicate that the number of taxa in Bjerkandera has been underestimated by morphological evidence, and may actually be greater than traditionally accepted.

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