Nuevos datos acerca de la singularidad fitogeográfica de las Sierras de Algeciras (Cádiz): Sphagnum platyphyllum en la Sierra de la Palma

The study of a bryophytes samples from the neighbourhood of Los Barrios (Cádiz) reveals the existence of two species of Sphagnum of the Subsecunda section: S. denticulatum Brid. (= S.lescurii Sull., S.auriculatum Schimp.) and S.platyphyllum (Braith.) Warnst. The first species had been already mentioned in the province of Cádiz, but the second one was unknown in Andalusia. The presence of this latter species with circumpolar distribution (Karlin, 1991) is a peculiar addition to the group of elements which a geobotanical meaning to the southern mountanious area of the province of Cádiz.Al examinar unas muestras de briófitos recolectadas en las proximidades de Los Barrios (Cádiz), identificamos dos especies de Sphagnum de la sección Subsecunda: S.denticulatum Brid. Sull. (= S.lescurii Sull., S.auriculatum Schimp.) y S.platyphyllum (Braithw.) Warnst. El primero ya había sido mencionado en la provincia de Cádiz, no sucediendo lo mismo con el segundo que no se conocía de Andalucía. La presencia de esta especie, de distribución fundamentalmente circumpolar (Karlin, 1991), proporciona un dato florístico más a añadir al conjunto de elementos que hacen de estas serranías meridionales gaditanas una zona de particular significación geobotánica

Algunos taxones de interés en el NW de la Península Ibérica.

. The presence of Araujia seric¡ifera in Galicia, a rare naturalized plant in the Iberian Peninsula, is reponed. 18 taxa colected in NW Spain are also commented in order to tbeir chorological or ecological interest.. Se indica la presencia en Galicia de Araujia sericifera planta naturalizada en escasos puntos de la Península Ibérica. Se señalan también otros 18 taxones herborizados en el NW peninsular, comentados en orden a su interés corológico y ecológico

Taxonomic differences between Pinus sylvestris and P. uncinata revealed in the stomata and cuticle characters for use in the study of fossil material

Taxonomic differences in the needle epidermis characteristics of Pinus sylvestris L. and Pinus uncinata Ramond ex DC. from two Iberian populations were sought; such information could help identify these species when pollen analysis and the inspection of wood anatomy fails. The features of the cuticle are commonly well preserved in the fossil record. Although the epidermal patterns of the examined taxa were similar, qualitative differences were seen in the subsidiary and guard cells. P. sylvestris showed small subsidiary cells homogenously arranged around the opening of the epistomatal chamber, while P. uncinata showed small, lateral subsidiary cells and non-differentiated subsidiary cells in the polar position. The aperture of the epistomatic chamber of P. uncinata was also larger in diameter (15.1 ± 1.8 µm P. sylvestris; 21.1 ± 2.8 µm P. uncinata). Principal components analysis and discriminant analysis was performed on the features of the guard cells characterising the size and shape of the cuticular thickenings — all the variables analysed can be measured in disperse stomata in microscope preparations for pollen analysis. Significant differences were found in the upper woody lamellae width and the coefficient associated with the shape of the medial lamellae borders (discriminant analysis weighting 0.739 and 0.826 respectively). Other significant parameters included the coefficient associated with the relative size of the medial lamellae border width of the guard cells with respect to the distance between the external limits of the medial lamellae borders, and the length of the upper woody lamella. Different light regimens appeared not to significantly affect the variability of the studied features

Abedulares de la Sierra de San Mamede (Orense, España).

En el presente trabajo se aborda el estudio de las formaciones de abedul en el límite meridional de la región galaica. Se describe su estructura, composición florística y se establece su dinamismo tanto progresivo como regresivo. Asi mismo se propone su inclusión en la asociación Luzulo henriquesii-Betuletum (TM/mi-tecle Rivas Martínez 1964.Complementariamente se aportan datos sobre su situación actual y se plantean diversas alternativas para su conservación.In this paper a study of the birch-tree forest along the south limit of the "Galaica" region is done. Their structure and floristic composition is described. It is appointed both their progresive and degradating dynamism. It is also suggested the inclusion of these forest in the phytological association Luzulo henriquesii-Betuletum celtihericae Rivas Martínez 1964. Their actual situation is commented too and several proceeding for their conservation are suggested

Floating millenial chronologies of Pinus in the Sierra de Gredos (Spain)

This research has been carried out by some members of the “History and Dynamics of the Vegetal Landscape” Research Group of the Technical University of Madrid (Spain). The team has been working on the flora, vegetation and dendrochronology of the Sierra de Gredos (Ávila, Spain) for the last 20 years. Recently, we have implemented a new research field focused on the study of megafossils. All this data set has allowed us to develop an interpretation of the dynamics of mountain pine forests in this region

A taxonomic tool for identifying needle remains of south-western European Pinus species of the Late Quaternary

Primer trabajo a nivel mundial sobre la diferenciación de especies de Pinus con clave dicotómica a través de la estructura cuticula

A taxonomic tool for identifying needle remains of south-western European Pinus species of the Late Quaternary

This work provides a tool whereby the needle remains of native, south-western European Pinus spp. can be easily identified from species-specific epidermal features. To construct this tool, the needles of P. uncinata, P. sylvestris, P. nigra, P. pinaster, P. pinea and P. halepensis were gathered across the Northern Hemisphere range of each taxon and compared with non-indigenous trees growing in two South Australian Botanic Gardens. Three needles from each of these species were taken from three adult trees growing at three different localities. Light microscopy was used to observe the key epidermal and stomatal features of the needles. To improve interpretation, additional scanning electron microscopy samples were prepared. Epidermal features, including variation in the diameter of the epistomatal chamber aperture (pore), are described. A taxonomic key based on the size, shape and arrangement of the subsidiary cells of the stomatal complexes was constructed. This key enables the identification of pine needle fragments at the species level (except those belonging to the group P. gr. nigra-uncinata). Despite their overlapping range, pore size was helpful in distinguishing between P. nigra and P. uncinata and between three groups of species. Isolated stomata were also observed. Cluster and discriminant analyses of stomatal variables described in earlier studies were performed. Overlap in guard cell variables hampers species-level identification of isolated stomata. Species discrimination is improved if groups of ecological affinity are considered

Los pastos en las fincas de Lugar Nuevo y Selladores-Contadores (Sª de Andújar, Jaén): tipología, calidad y distribución espacial

Las fincas del O. A. Parques Nacionales “Lugar Nuevo” y “Selladores-Contadero” están situadas en el Parque Natural de la Sierra de Andújar (Jaén). Su situación geográfica, y especialmente su historia de usos y propiedad han motivado que hoy sean ejemplo de una flora y vegetación con buen estado de conservación. En trabajos anteriores se han realizado catálogos florísticos de las dos fincas como estudios básicos para la planificación de la gestión y la compatibilidad de la conservación y el aprovechamiento de los recursos en los espacios naturales protegidos. En esta comunicación se realiza un análisis de los pastos herbáceos de las dos fincas que constituyen un recurso estratégico para la alimentación de las poblaciones de herbívoros instaladas en las mismas. Se analizan y cartografían las distintas formaciones de pastos reconocidos (10), su distribución espacial, palatabilidad y grado de utilizació

The past distribution of pinus nigra arnold in northern iberia. Contribution from its macroremains.

The presence of Pinus nigra in central Spain, where its natural populations are very rare, has led to different interpretations of the current vegetation dynamics. Complementary to the available palynological evidence, macroremains provide local information of high taxonomic resolution that helps to reconstruct the palaeobiogeography of a given species. Here we present new macrofossil data from Tubilla del Lago, a small palaeolake located at the eastern part of the northern Iberian Meseta. We identified 17 wood samples and 71 cones on the basis of their wood anatomy and morphology, respectively. S ome of the fossil samples were radiocarbon dated (~4.230-3210 years cal BP). The results demonstrate the Holocene presence of P. nigra in the study area, where it is currently extinct. This evidence, together with other published palaeobotanical studies, indicates that the forests dominated by P. nigra must have had a larger importance on the landscape prior to the anthropogenic influence on the northern Iberian Meseta

Floristic changes in the Iberian Peninsula and Balearic Islands (south-west Europe) during the Cenozoic

AIM  The aim of this work was to identify the main changes in the flora and vegetation of the Iberian Peninsula over the Cenozoic Era, to record the disappearance of taxa associated with these changes and to determine the influence of climate and human activity on these events. Location  The Iberian Peninsula and Balearic Islands. METHODS  A critical review was made of the palaeobotanical literature with the aims of detecting patterns of floristic change and extracting information on the disappearance of different taxa over the Cenozoic. These data are viewed alongside the most recent data for the climate of this period. A critical analysis is made of the role of Palaeotropical and Arctotertiary taxa in the forest communities of the Iberian Peninsula throughout the Cenozoic. RESULTS  Although the Eocene–Oligocene transition was a time when many taxa disappeared, the most outstanding events occurred between the end of the Oligocene and throughout the Miocene. Substantial floristic changes took place over this period, including the disappearance of 177 Palaeotropical taxa. This was probably related to acute cooling and aridification; no evidence exists that the Messinian Salinity Crisis had any important effect in the Iberian Peninsula. The last great disappearance of Palaeotropical taxa (36 in total) ended in the Middle–Late Piacenzian; Arctotertiary taxa were most affected during the Pleistocene. The Lower–Middle Pleistocene transition, best represented by marine isotopic stages (MIS) 36–34 and 20–18 and characterized by a change in glacial cyclicity, was the time of the last notable disappearance of taxa. MAIN CONCLUSIONS  This work provides the first chronogram of extinctions for the Iberian flora, and records the disappearance of 277 taxa during the Cenozoic. A clear relationship was detected between the main climatic events and the latest appearances of the different taxa