Aleurocystis gloeocystidiata sp. nov. on Polylepis australis in Argentina

The new taxon Aleurocystis gloeocystidiata is described, growing on living ranchlets of Polylepis australis in Central Argentina. It is characterized by a discoid-cupuloid basidiome, ellipsoid basidiospores 17-24 x 12-15 µm, metuloid cystidia, sulfonegative gloeocystidia, clamped, non-gelatinized generative hyphae, and encrusted skeletocystidia that are present in the context, form the white, hairy margin of the basidiome, and become grayish in Melzerʼs reagent.Fil: Robledo, Gerardo Lucio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Rajchenberg, Mario. Centro de Investigación y Extensión Forestal Andino Patagónico; Argentin

South American polypores : first annotated checklist from Argentinean Yungas

A preliminary checklist of the polypore mycota of “Yungas”, subtropical mountain forests of northwestern Argentina, is presented. An intensive search of records in literature was done, and polypore exsiccatae from that phytogeographic province kept at the main Argentinean herbaria were studied. A total of 850 specimens were revised and 111 species were determined. Phellinus laevigatus and Skeletocutis stellae are recorded for the first time in South America; 8 species are new records for Argentina and 31 new records for the region. The new combination Dichomitus hexagonoides is proposed. The complete checklist is available on: http://www.mycotaxon.com/resources/weblists.html.Fil: Robledo, Gerardo Lucio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Rajchenberg, Mario. Centro de Investigación y Extensión Forestal Andino Patagónico; Argentin

Kavinia chacoserrana sp. nov. (Gomphales, Basidiomycota): a new species from South America based on morphological and molecular data

Kavinia chacoserrana is described as a new species based on morphological data and molecular evidence. The species is characterized by its white to pale yellowish hydnoid hymenophore and cylindrical to fusiform basidiospores measured as 10-12 × 3-4 μm. Phylogenetic analysis provide evidence suggesting that, as currently accepted, Kavinia alboviridis is a species complex.Fil: Robledo, Gerardo Lucio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Urcelay, Roberto Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentin

Hymenochaetaceae from Paraguay: Revision of the family and new records

A synopsis of species of Hymenochaetaceae from five departments of Paraguay (Alto Paraguay, Boqueron, Central, Cordillera and Paraguari) is presented. Thirteen species from nine genera are reported, of which eleven are recorded for the first time. Descriptions and macro-and microscopic illustrations are presented for each species. Discussions on their taxonomy and ecology are provided.Fil: Maubet, Y.. Universidad Nacional de Asunción; ArgentinaFil: Campi, M.. Universidad Nacional de Asunción; ArgentinaFil: Robledo, Gerardo Lucio. Universidad Nacional de Córdoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Fundación Fungicosmos Www.fungicosmos.org; Argentin

Taxonomy and Systematics of fungi from South America –a special issue in honoring Leif Ryvarden: Introduction

Since the ending of the nineteen century and the beginning of the last one, pioneered by mycologists such as Carlos Spegazzini, A. Giacomo Bresadola, Johann Rick and Miles Joseph Berkeley, mycological research in South America has grown vigorously and continues in the present time. Numerous taxa have been described, many papers have been published, and several regional mycotas have been produced. One of the major contributors in this field is Professor Leif Ryvarden, who has made substantial contributions to the knowledge of polypore diversity in his series of articles Neotropical polypores, where he describes patterns of polypore distribution and putforth clever hypotheses about the processes behind those patterns. In addition he worked closely with several local mycologists (Fig. 1). The contributions of Dr. Ryvarden are not restricted to South America or to polypores. It would be a quite difficult task to enumerate Ryvarden´s overall contributions to the field of mycology, but for any mycologist it is clearly evident that his contributions –more than three hundred published articles and books– extend all around the world and substantially improved our knowledge on fungal diversity on a global scale. It is for this reason that we have dedicated this special issue of Kurtziana to Professor Leif Ryvarden in honour of his devotion to South American mycology.Fil: Urcelay, Roberto Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Romero, Andrea Irene. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Micología y Botánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Micología y Botánica; ArgentinaFil: Robledo, Gerardo Lucio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentin

Phylogeny of <i>Potamogeton</i> (Potamogetonaceae) revisited: implications for hybridization and introgression in Argentina

Potamogeton is a cosmopolitan genus of 90–95 species in which numerous hybridization events have occurred worldwide. A plant recently collected from Argentina exhibited ambiguous morphology that does not match any species of the genus. We aimed to assess if the plant coexisting with another Potamogeton species is a product of reticulate evolution. A concatenated plastid DNA (psbA-trnH, trnL intron, and trnL-trnF) and nuclear ribosomal DNA (5S-NTS) data sets, primarily based on previous studies sample set mainly consisting of American and Asian species, were analyzed using Bayesian inference. Nuclear ribosomal ITS sequences were also obtained from five Argentina materials. We recovered similar topologies from both the plastid DNA and nuclear ribosomal 5S-NTS analyses in which most specimens are consistently placed. The specimen of primal interest from Argentina strongly clustered with co-occurring linear-leaved species in the 5S-NTS tree, but was genetically identical to broad-leaved ones in the plastid DNA analysis. The ITS sequence of the specimen was the same as that of the linear-leaved species and no polymorphisms were observed. Considering the discrepant phylogenetic positions between the trees and lack of ITS infra-individual variations, the origin of the specimen from Argentina is better explained by hybridization and subsequent introgression.Facultad de Ciencias Naturales y Muse

Phylogeny of <i>Potamogeton</i> (Potamogetonaceae) revisited: implications for hybridization and introgression in Argentina

Potamogeton is a cosmopolitan genus of 90–95 species in which numerous hybridization events have occurred worldwide. A plant recently collected from Argentina exhibited ambiguous morphology that does not match any species of the genus. We aimed to assess if the plant coexisting with another Potamogeton species is a product of reticulate evolution. A concatenated plastid DNA (psbA-trnH, trnL intron, and trnL-trnF) and nuclear ribosomal DNA (5S-NTS) data sets, primarily based on previous studies sample set mainly consisting of American and Asian species, were analyzed using Bayesian inference. Nuclear ribosomal ITS sequences were also obtained from five Argentina materials. We recovered similar topologies from both the plastid DNA and nuclear ribosomal 5S-NTS analyses in which most specimens are consistently placed. The specimen of primal interest from Argentina strongly clustered with co-occurring linear-leaved species in the 5S-NTS tree, but was genetically identical to broad-leaved ones in the plastid DNA analysis. The ITS sequence of the specimen was the same as that of the linear-leaved species and no polymorphisms were observed. Considering the discrepant phylogenetic positions between the trees and lack of ITS infra-individual variations, the origin of the specimen from Argentina is better explained by hybridization and subsequent introgression.Facultad de Ciencias Naturales y Muse

Neofavolus subpurpurascens comb. nov., with new records from the Neotropics

Polyporus subpurpurascens is a rare Neotropical species characterized by deep purplish pilear surface and radially elongated pores. This study analyzed Neotropical specimens from Argentina, Bolivia and Brazil by applying detailed morphological examination and phylogenetic analyses. We conclude that P. subpurpurascens is a species of Neofavolus, and N. subpurpurascens is proposed as a new combination. New records from Argentina and Bolivia, a detailed description, and photographs of the species are included.Fil: Palacio, Melissa. Universidade Federal do Rio Grande do Sul; BrasilFil: Silveira, Rosa Mara Borges Da. Universidade Federal do Rio Grande do Sul; BrasilFil: Robledo, Gerardo Lucio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentin

Network reliability analysis and intractability of counting diameter crystal graphs

Consider a stochastic network, where nodes are perfect but links fail independently, ruled by failure probabilities. Additionally, we are given distinguished nodes, called terminals, and a positive integer, called diameter. The event under study is to connect terminals by paths not longer than the given diameter. The probability of this event is called diameter-constrained reliability (DCR, for short). Since the DCR subsumes connectedness probability of random graphs, its computation belongs to the class of NP-Hard problems. The computational complexity for DCR is known for fixed values of the number of terminals k n and diameter d, being n the number of nodes in the network. The contributions of this article are two-fold. First, we extend the computational complexity of the DCR when the terminal size is a function of the number of nodes, this is, when k = k(n). Second, we state counting diameter-critical graphs belongs to the class of NP-Hard problems