El género Pannaria (Pannariaceae) en la Argentina: nuevos registros y actualización del conocimiento

Introducción & Objetivos: Como parte de estudios a largo plazo enfocados en la diversidad de hongos liquenizados en la Argentina, se presenta una revisión sobre el género Pannaria para el país. Este género nunca ha sido estudiado en detalle en nuestro territorio.  M&M: La morfología, anatomía y química de las especies fue estudiada por medio de la revisión de ejemplares frescos recolectados en el campo y el estudio de diferentes colecciones de herbario, siguiendo protocolos estandarizados.  Resultados: Se registraron 15 especies de Pannaria, 3 de ellas por primera vez para la Argentina: P. canoplea, P. malmei y P. tavaresii. Se propone una nueva sinonimia (P. euphylla = P. calophylla). Se presentan descripciones, fotografías e información actualizada sobre la distribución y ecología de las especies, y una clave para su identificación.  Conclusiones: La mayoría de las especies mencionadas se encuentran en los bosques andino-patagónicos, con la excepción de P. canoplea, P. malmei y P. tavaresii, que se encontraron en el centro de Argentina, en bosques de altura de Polylepis.

Two new records of the family Lobariaceae (Lichenized Ascomycota: Peltigerales) from Argentina

As part of long term studies focused in the lichenized mycobiota diversity from southern Argentina, two species of the family Lobariaceae (Peltigerales), Pseudocyphellaria pluvialis and Sticta longipes, are registered for the first time in Argentina. These species were previously reported as endemic from southern Chile. Brief descriptions, illustrations and information about the distribution and ecology of the species are provided.

A multigene phylogenetic synthesis for the class Lecanoromycetes (Ascomycota): 1307 fungi representing 1139 infrageneric taxa, 317 genera and 66 families

The Lecanoromycetes is the largest class of lichenized Fungi, and one of the most species-rich classes in the kingdom. Here we provide a multigene phylogenetic synthesis (using three ribosomal RNA-coding and two protein-coding genes) of the Lecanoromycetes based on 642 newly generated and 3329 publicly available sequences representing 1139 taxa, 317 genera, 66 families, 17 orders and five subclasses (four currently recognized: Acarosporomycetidae, Lecanoromycetidae, Ostropomycetidae, Umbilicariomycetidae; and one provisionarily recognized, 'Candelariomycetidae'). Maximum likelihood phylogenetic analyses on four multigene datasets assembled using a cumulative supermatrix approach with a progressively higher number of species and missing data (5-gene, 5+4-gene, 5+4+3-gene and 5+4+3+2-gene datasets) show that the current classification includes non-monophyletic taxa at various ranks, which need to be recircumscribed and require revisionary treatments based on denser taxon sampling and more loci. Two newly circumscribed orders (Arctomiales and Hymeneliales in the Ostropomycetidae) and three families (Ramboldiaceae and Psilolechiaceae in the Lecanorales, and Strangosporaceae in the Lecanoromycetes inc. sed.) are introduced. The potential resurrection of the families Eigleraceae and Lopadiaceae is considered here to alleviate phylogenetic and classification disparities. An overview of the photobionts associated with the main fungal lineages in the Lecanoromycetes based on available published records is provided. A revised schematic classification at the family level in the phylogenetic context of widely accepted and newly revealed relationships across Lecanoromycetes is included. The cumulative addition of taxa with an increasing amount of missing data (i.e., a cumulative supermatrix approach, starting with taxa for which sequences were available for all five targeted genes and ending with the addition of taxa for which only two genes have been sequenced) revealed relatively stable relationships for many families and orders. However, the increasing number of taxa without the addition of more loci also resulted in an expected substantial loss of phylogenetic resolving power and support (especially for deep phylogenetic relationships), potentially including the misplacements of several taxa. Future phylogenetic analyses should include additional single copy protein-coding markers in order to improve the tree of the Lecanoromycetes. As part of this study, a new module ("Hypha") of the freely available Mesquite software was developed to compare and display the internodal support values derived from this cumulative supermatrix approach.

Joergensenia, a new genus to accommodate Psoroma cephalodinum (lichenized Ascomycota)

The taxonomy of the genus Psoroma (lichenized Ascomycota) is currently under revision, as it has long been recognized as heterogeneous. The aim of the present study was to reconstruct the phylogeny of Psoroma and related genera. The ITS region of nu-rDNA and the mtSSU rDNA from 22 collections of Psoroma and Pannaria were amplified. Sequences from GenBank were also used. For the phylogenetic analysis, direct optimization was implemented, using the program POY, and standard MP using PAUP. Both analyses resulted in similar trees. Two main clades were obtained, one including Santesoniella and most Psoroma species and the other including Pannaria and two Psoroma species, indicating that Psoroma is polyphyletic. Based on its phylogenetic position and ascus type, P. implexum is transferred to the genus Pannaria, and the new combination P. implexa is proposed. Psoroma cephalodinum clusters with Parmeliella and Degelia as a basal group within the Pannariaceae. The ascus apex of P. cephalodinum has a strong amyloid reaction revealing a compact cap-shaped plug. This differs from most of the ascus apical structures observed in the family. Both ascus internal structure and phylogenetic position suggest that P. cephalodinum is distantly related to Psoroma or Pannaria, and thus a new genus Joergensenia is proposed.

Trunk and main-branch development in Nothofagus pumilio (Nothofagaceae): a retrospective analysis of tree growth

The development of the trunk and main branches of approximately 26-year-old Nothofagus pumilio (Poepp. et Endl.) Krasser trees was studied. The length and number of leaves of annual shoots were recorded for 56 trees from a natural population. Morphological and macroanatomical features allowed the identification of shoot apex deaths and the axillary positions from which branches and relay shoots derived. The trees had a mean height of approximately 6 m and a mean basal diameter of approximately 8 cm. The length of trunk shoots increased from the first years to the intermediate years of tree growth and decreased for the last 6 years of tree growth. The maximum length and number of leaves of trunk shoots were registered for the years around 1985, when tree age was about 17 years. The likelihood of apex death for trunk shoots was minimum for the period of maximum trunk shoot size. Despite the fact that the architectural features of the sampled trees corresponded to those of young, vigorously growing trees, they seemed to have reached a stage of low annual height growth. A sharp decrease in trunk shoot size occurred in 1992, a year in which rainfall during the growing season reached the minimum for the lifetime of the sampled trees. The size of shoots developed after 1992 was, on average, lower than that of shoots developed before 1992. Stressful conditions in this year may relate to meristem ageing and thus to the size of shoots formed in the following years. Main branches started their development with shoots similar to those of the trunk but were clearly differentiated from the trunk 5 years later. The differentiation between main branch and trunk shoots involved not only a lower shoot size but also a higher number of leaves per shoot length unit in main branch than in trunk shoots.Key words: Nothofagus pumilio, architectural analysis, shoot, trunk development, branching pattern, morphogenetic gradient.