Consulta: subjectFacets:"Gymnosperms"
Registros recuperados: 3
Data/hora: 09/06/2024 15:31:12

A new araucarian fossil species from the Paleogene of southern Argentina
Provedor de dados: 41
Autores: Panti,Carolina; Césari,Silvia N.; Marenssi,Sergio A.; Olivero,Eduardo B.
A new Araucariaceaea from the Paleogene of Tierra del Fuego Province, Argentina is described. Araucaria pararaucana sp. nov. has imbricate, ovate-lanceolate leaves with an acute apex, characterized by the presence of discontinuous and longitudinally oriented stomatal rows separated by epidermal cells, which may be slightly sinuous. Stomatal guard cell surface is granular. These fossil leaves are compared with the extant sections Bunya, Intermedia and Araucaria. Their anatomical characters along with the external morphology suggest a close affinity with the extant southern Patagonian species A. araucana (Molina) K. Koch. The record of this new late Eocene species provides more evidence for a probable unique representation of Section Araucaria in the area...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Gymnosperms; Araucariaceae; Araucaria; Cuticle; Paleogene; Argentina.
Ano: 2007
URL: http://www.scielo.org.ar/scielo.php?script=sci_arttext&pid=S0002-70142007000100016

Charcoal remains from a tonstein layer in the Faxinal Coalfield, Lower Permian, southern Paraná Basin, Brazil
Provedor de dados: 42
Autores: Jasper,André; Uhl,Dieter; Guerra-Sommer,Margot; Abu Hamad,Abdalla M. B; Machado,Neli T. G.
Fossil charcoal has been discovered in the Faxinal Coalfield, Early Permian, Rio Bonito Formation, in the southernmost portion of the Paraná Basin, Brazil. Three types of pycnoxylic gymnosperm woods recovered from a single tonstein layer are described and confirm the occurrence of paleowildfire in this area. A decrease of the charcoal concentration from the base to the top within the tonstein layer indicates that the amount of fuel declined during the deposition probably due to the consumption of vegetation by the fire. The presence of inertinite in coals overlying and underlying the tonstein layer indicates that fire-events were not restricted to the ash fall interval. The integration of the new data presented in the current study with previously...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Charcoal; Gymnosperms; Volcanic ashes; Coal deposits; Gondwana; Late Palaeozoic.
Ano: 2011
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652011000200009

The adaptive value of shoot differentiation in deciduous trees and its evolutionary relevance
Provedor de dados: 51
Autores: Dörken,Veit M.; Stützel,Thomas.
Pronounced long shoot/short shoot differentiation is typical for deciduous angiosperm trees. It also occurs in a number of gymnosperms and very few evergreen angiosperm trees. The study of 719 angiosperm tree species (602 deciduous and 117 evergreen species) demonstrated that the deciduous condition is nearly always associated with shoot differentiation. Detailed measurements in 38 angiosperms showed that the leaf area of an entire short shoot equals the leaf area of a single long shoot leaf of the same species and individual. In the few cases where the leaf area of the short shoot is slightly larger than that of a single long-shoot leaf, the short shoot leaves shade each other and the projection of the short shoot equals the area of a single long shoot...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Shoot differentiation; Deciduous trees; Angiosperms; Gymnosperms; Evolution; Phytogeography.
Ano: 2009
URL: http://www.scielo.org.ar/scielo.php?script=sci_arttext&pid=S1851-23722009000200017