Wanderley M.G.L.,Institute Botanica
PhytoKeys | Year: 2017
A nomenclatural revision of fifteen taxa of Xyris (Xyridaceae) described by L.A. Nilsson (1892) is presented as part of a taxonomic revision of the genus in Brazil. All the protologues and type collections of these taxa were studied. The type collections were examined in the respective herbarium collections where they are preserved and complemented by images available on herbarium websites and from JSTOR Global Plants. Lectotypes were selected for Xyris cristata L.A.Nilsson, X. glaziowii L.A.Nilsson and X. insignis L.A.Nilsson. The holotypes, of X. glandacea L.A.Nilsson and X. stenophylla L.A.Nilsson, were discovered at the herbaria of Uppsala (UPS) and Berlin (B) respectively, and provided with their correct determinations. © Maria das Graças Lapa Wanderley.
Turchetto-Zolet A.C.,Federal University of Rio Grande do Sul |
Pinheiro F.,Institute Botanica |
Salgueiro F.,UNIRIO |
Palma-Silva C.,Institute Botanica
Molecular Ecology | Year: 2013
The South American continent is composed of several biogeographical regions harbouring the highest biodiversity on the globe, encompassing five of the world's biodiversity 'hot spots'. Nonetheless, the patterns and processes responsible for shaping its astonishing species diversity are largely unknown. Here, we present a review of current South American phylogeographical knowledge based on published articles on this topic. An appraisal of the literature reveals emerging phylogeographical patterns in the biota of South America. The striking phylogeographical divergence observed among organism lineages in South American studies is suggestive of high levels of undocumented species diversity. The interplay between Pleistocene climatic oscillations and Pliocene/Miocene orogenic events has contributed to shaping the current diversity and distribution of modern lineages in both the tropical and temperate regions of South America. Although older divergence times were observed for a range of species, most herpetofauna underwent an intraspecific lineage split much earlier than other organisms. The geographical ranges of species associated with forest habitats were reduced mainly during glacial cycles, whereas species associated with open vegetation domains have shown variable responses to climatic oscillations. The results suggest a highly complex mosaic of phylogeographical patterns in South America. We suggest future research directions to promote a better understanding of the origin and maintenance of the South American biota. © 2012 Blackwell Publishing Ltd.
Pinheiro F.,Institute Botanica |
Cozzolino S.,University of Naples Federico II
Taxon | Year: 2013
The orchid genus Epidendrum, with 1500 species occurring within the Neotropical region, represents a very promising model system for evolutionary and ecological studies offering an expanded repertoire of research opportunities in the breadth of modern plant biology. Epidendrum displays a significant degree of morphological variation, chromosome number diversity and ecological interactions, which challenges widely held views on reproductive barriers and habitat selection. The widespread geographical distribution of many species and populations offers interesting opportunities to investigate how climatic changes and historic demographic processes shaped the current patterns of genetic and species diversity across different biomes and landscapes. Questions involving chromosome barriers to gene exchange and the role of postzygotic genetic barriers in species cohesion (e.g., the contributions of habitat selection and niche divergence on species cohesion) could be easily addressed when using the variety of natural hybrid zones found across Epidendrum. Several key evolutionary questions could be addressed with this model system, such as the identification of the first stages of adaptive radiation, the evolution of pollination strategies, the adaptive ecological significance of trait variation and hybridisation, the influence of historical demographic events on lineage diversification and speciation. With the advance of cost-effective molecular techniques and by combining ecological and phenotypic data, researchers can now tackle these questions and foster significant progress in the field of Neotropical plant diversification and evolution.
Fonseca B.M.,Catholic University of Brasília |
Bicudo C.E.D.M.,Institute Botanica
Journal of Plankton Research | Year: 2010
This study aimed at comparing phytoplankton taxonomic classes and morpho-functional attributes in two shallow tropical reservoirs with different nutrient levels and representing extremes of the alternative stable states theory. The reservoirs, locally called Ninféias Pond (23°38′18. 95″S; 46°37′16.3″W) and Garças Pond (23°38′40.6″S; 46°37′28.0″W), are located in the city of São Paulo, southeastern Brazil. Ninféias Pond is oligo-mesotrophic and has abundant submerged macrophytes; Garças Pond is eutrophic without submerged macrophytes, with cyclic cyanobacterial blooms. Sampling was carried out monthly from January to December 1997. Phytoplankton species were classified according to taxonomic classes and the following criteria: life form, size, biovolume, life strategy (C-S-R) and functional group. Statistical differences in taxa contribution were reported for both lakes considering all criteria tested, especially life forms. Taxonomic classes dominating Ninféias Pond were Prymnesiophyceae and Dinophyceae, which strongly influenced a community characterized by nanoplanktonic unicellular flagellated C/S-strategists, and the main functional groups were X2, L O and W1. Garças Pond phytoplankton community was dominated by species belonging to Cyanobacteria and colonial non-flagellated nano/micro-planktonic S-strategists, and the main functional groups were M, SN and LM. Differences in trophic status are probably the main factor triggering such differences. However, the presence of macrophytes in Ninféias Pond also seems to qualitatively influence its phytoplankton community, favoring flagellated species.
Luz C.F.P.D.,Institute Botanica
Grana | Year: 2016
Ephedra tweediana is one of few gymnosperms native to Brazil and the sole species of the Ephedraceae family. The present work examines the pollen grains of E. tweediana using light and scanning electron microscopy in order to obtain additional morphological data and to help to identify it in its fossil forms. Ephedra tweediana pollen grains are monad, medium sized, ellipsoidal, inaperturate, characterised by a series of psilate longitudinal ridges (or plicae), typically ten, with small polar apices that protrude. The wide gently domed ridges are straight and psilate, separated by a psilate region (furrows) with a distinct, unbranched, slightly undulating hyaline line formed by the thinning of the sexine located in the middle of the furrow area. The granular sexine at the crest of a plica is composed of a homogeneous tectum, below which an infratectum is apparent. The infratectum disappears into the furrows. The nexine is uniform in thickness in all regions. Pollen of E. tweediana is characterised by the merging of the Steeves and Barghoorn’s Type C and D. However, occasional pollen grains of the Type B occur with undulant ridges. The pollen grains of E. tweediana resemble those of E. trifurca and E. chilensis (syn. E. andina in Steeves and Barghoorn’s work). Few pollen grains resemble the E. chilensis presented by these authors in Type B. This similarity hinders the identification of these American species in sediments containing microfossils. © 2015 Collegium Palynologicum Scandinavicum.
Benatti M.N.,Institute Botanica
Mycology | Year: 2011
Bulbothrix caribensis and B. lyngei are two new lichen species discovered during a systematic revision of the genus. The first species lacks medullary substances and the second species produces an undetermined fatty acid. © 2011 Copyright 2011 Mycological Society of China.
Benatti M.N.,Institute Botanica
Mycology | Year: 2012
Bulbothrix pseudofungicola and B. silicisrea are two new lichen species discovered during a systematic revision of the genus; both containing gyrophoric acid as a medullary substance. © 2012 Copyright 2012 Mycological Society of China.
Capelari M.,Institute Botanica
Mycotaxon | Year: 2011
The study of Agaricales collections gathered in the northwest region of São Paulo State, Brazil revealed the occurrence of four species of Crepidotus. Two of them, C. flavus and C. longicystidiatus, are proposed as new, while C. apodus and C. defibulatus are recorded for the first time in the northwest region of São Paulo State. © 2011. Mycotaxon, Ltd.
Esteves L.M.,Institute Botanica
Anuario do Instituto de Geociencias | Year: 2013
The spores of ferns and lycophytes may be deposited on the soil, and by various mechanisms, they can be moved down into and through the soil, although usually remaining in the superficial layers. They may persist in the soil for some time in a dormant state, and when brought back to the surface they will germinate. Such living spores stored in the soil comprise what is called a soil spore bank. Spore banks can reduce the risk of extinction of species, allowing the regeneration of a population in an area devastated by floods, fires, droughts, landslides or succession processes. Thus, they have a function similar to that of seed banks in spermatophytes. In the majority of ferns and lycophytes the spores are positively photoblastic. This has adaptive value since it makes them dormant when buried and potentially able to germinate when brought to the surface. The regeneration of persistent spore banks can also increase the possibilities of crossing between gametophytes of colonizing species. They also function as a buffer against the consequences of low spore production in years with adverse weather conditions, and against drastic changes in the genetic composition during fluctuations in population size, such that only long-term changes in the environment can substantially alter its composition. Moreover, genotypes that were apparently lost can be recovered from the spore bank.
Benatti M.N.,Institute Botanica
Opuscula Philolichenum | Year: 2013
This study is a taxonomic review of nine species of Bulbothrix (Parmeliaceae, lichenized fungi) containing gyrophoric, lecanoric or lobaric acids and whose thalli do not form isidia, soredia or pustules. The current species delimitations are confirmed. New characteristics are detailed, some synonyms are rejected, others confirmed, and range extensions are given. Lectotypes are selected for Parmelia coronata (= B. coronata) and P. glandulifera (= B. coronata).