Taller de matem��gicas

Presentamos una experiencia desarrollada durante la celebraci��n de la Semana Cultural del LB. ���Virgen de Valme��� de Dos Hermanas (Sevilla), bajo el nombre de ���Taller de Matem��gicas���, en el curso 89/90. Con ello no s��lo buscamos que otros compa��eros se animen a la realizaci��n de actividades de este tipo, sino fundamentalmente que estas vayan ganado cada vez m��s terreno en su introducci��n en las programaciones de la asignatura de Matem��ticas.

Generador de vol��menes

Nos parece interesante dar a conocer este ��til did��ctico, entre otras razones, por su sencillez de manejo, por su e���cacia y su bajo costo. Su construcci��n es muy sencilla y con ��l se pueden conseguir resultados extraordinanarios.

Contribution to the knowledge of the genus "Cladonia" in Macaronesia

Sixteen species of the genus Cladonia are reported from Macaronesia from the Canary Islands. Three species are new to canarian flora and, two of them new to Macaronesia. The chemical variation of the taxa is reported. A phytogeographic distribution of the taxa with data on their habitat and ecology are presented.

Contributions to the bryological flora of the tropical and subtropical forests from the Argentina (Bryophyta, Musci).

The authors present here a list of 32 mosses belonging to 15 families: Brachytheciaceae, Cryphaeaceae, Entodontaceae, Hedwigiaceae, Hypnaceae, Leptodontaceae, Meteoriaceae, Neckeraceae, Pilotrichaceae, Polytrichaceae, Pterobryaceae, Racopilaceae, Rigodiaceae, Stereophyllaceae, and Trachypodaceae, all collected in the mountainous forests of the Yungas of the NW of the Argentina (Jujuy, Salta, Catamarca and Tucum��n provinces), and also in the rainforests from the NE of the country (Misiones province). Eight species: Atrichum polycarpum, Chrysohypnum elegantulum, Pilosium chlorophyllum, Pilotrichella flexilis, Porotrichodendron lindigii, Pseudotrachypus martinicensis, Steerecleus scariosus, and Thamnobryum fasciculatum are new records for the bryologic flora from Argentina. Braunia imberbis and Squamidium brasiliense are two new records for the bryophytic flora of the Catamarca province; Porotrichodendron superbum is new for the Salta province, while Forsstroemia coronata is the first record for the Catamarca and Jujuy provinces. Aerolindigia capillacea, Braunia reflexifolia, Chryso-hypnum diminutivum, Meteorium deppei and Meteoridium remotifolium are five new citations for the Jujuy province, and Schoenobryum concavifolium is new for the bryophytic flora of the Misiones province. Many studied species occur more frequently in the Yungas than in the NE rainforests; others show separated distribution but live in both areas, the Yungas and Paranaense area, and others are more or less restricted to the Paranaense rainforest of the NE of Argentina. The taxonomy of species is updated, and comments are included on bibliographical precedents, ecology and chorology of each taxon.

Contribution to the knowlegde of Galician xenoflora (NW Iberian Peninsula, Spain).

Information on 12 exotic plants of diverse interest for the Galician flora are presented. All of them were collected in Ribeira council (SW of the A Coru��a province). The total includes 8 novelties at a regional level (Aeonium haworthii, Aloe mitriformis, Brugmansia �� candida, Nephrolepis cordifolia, Osteospermum ecklonis, Pelargonium capitatum, Sedum mexicanum, Sparaxis tricolor), and 2 provincial novelties. In addition, information on two taxa hardly mentioned in the literature on Galician vascular flora is also included. All the cited specimens are deposited at the SANT Herbarium.

Diversity of functional groups in the vegetation sandy seashore of the Grande, Anclitas and Caguamas Cays (Jardines de la Reina Archipelago, Cuba)

Sandy shores are known to be extreme ecosystems where the vegetation has evolved many morphological and physiological adaptations for its survival. With the aim of identify possible relationships between the vegetation��s functional diversity with abiotic factors and its corresponding quantification, we collected data on the abundance and richness of the sandy coast vegetation complex in Grande, Anclitas and Caguamas keys. Its flora is largely characterized by the dominance of hemicryptophytes and chamaephytes plants with nanophyllous leaves and displaying dispersal syndromes such as zoochory and anemochory. However, the functional groups�� richness, in the present study, varies from one key to another. Functional diversity is similar between the wet and dry seasons, and its spatial variation is influenced by the interplay of the set of abiotic factors herein studied.

A couple of embroiled sheets of Miguel Barnades Manaider and Esteban de Prado in the Herbaria of Real Colegio Alfonso XII of San Lorenzo de El Escorial (Madrid)

In this paper we present a couple of sheets of Umbelliferae that are preserved in the RCAXII herbaria. One of them, Selinum carvifolia, where collected in the Gredos Mountains by Miguel Barnades Mainader and was identified by his son Miguel Barnades Clar��s. The other, Tragium flabellifolium, was collected in Mieres (Asturias) by Esteban de Prado and identified by Mariano La Gasca.

Both respiration and photosynthesis determine the scaling of plankton metabolism in the oligotrophic ocean

Despite its importance to ocean���climate interactions, the metabolic state of the oligotrophic ocean has remained controversial for 415 years. Positions in the debate are that it is either hetero- or autotrophic, which suggests either substantial unaccounted for organic matter inputs, or that all available photosynthesis (P) estimations (including 14C) are biased. Here we show the existence of systematic differences in the metabolic state of the North (heterotrophic) and South (autotrophic) Atlantic oligotrophic gyres, resulting from differences in both P and respiration (R). The oligotrophic ocean is neither auto- nor heterotrophic, but functionally diverse. Our results show that the scaling of plankton metabolism by generalized P:R relationships that has sustained the debate is biased, and indicate that the variability of R, and not only of P, needs to be considered in regional estimations of the ocean���s metabolic state.

An��lisis multivariable de la vegetaci��n de un complejo de turberas en Cordillera Pelada (Valdivia,Chile)

Se estudi�� la vegetaci��n en un gradiente de inclinaci��n de un complejo de turberas, en la cordillera costera de Valdivia, Chile. Se levantaron 17 censos de vegetaci��n, ubicados equidistantes en un transecto de 50 m. La tabla fitosociol��gica resultante se analiz�� con m��todos estad��sticos multivariables de ordenaci��n y de clasificaci��n. Adem��s, se determinaron algunas caracter��sticas qu��micas del sustrato. El transecto estudiado corresponde a una coenoclina, cuya parte alta es ocupada por un alerzal (Fitzroyeturn cupressoidis), en la zona intermedia se desarrolla una turbera ombrog��nica de Donatia fascicularis (Drosero-Donatieturn fascicularis) y, en la parte inferior, una topog��nica de Sphagnum magellanicum (Sphagnetum magellanicii). En las zonas ecotonales entre estas comunidades prosperan pantanos turbosos de Astelia pumila (Astelio-Oreoboletum obtusangulae) y de Marsippospermum philippii (Marsippospormo-Astelietum pumiliae) que muestran escasa diferenciaci��n flor��stica. Se proponen dos alianzas fitosociol��gicas nuevas Donation fascicularis (turberas de Donatia) y Astelion pumilae (pantanos de Astelia) para la clase Myrteolo-Sphagnetea Oberdorfer 1960. Los contenidos de materia org��nica y de agua del sustrato son los factores determinantes de estos patrones de distribuci��n. Finalmente, se analiza la posici��n fitogeogr��fica de las comunidades vegetales determinadas.

Comportamiento fitosociol��gico de Juniperus phoenicea L. s.l. en el sur de la Pen��nsula Ib��rica

Se ha realizado un estudio fitosociol��gico de las comunidades de Juniperus phoenicea L. s.l. en el sector Ronde��o. Como resultado del mismo se se��ala la presencia de Juniperus turbinata subsp. turbinata en territorios interiores de este sector y se describen dos nuevos sint��xones: Asparaqo horridi-Juniperetum turbinatae y Rhamno myrtifoliae-Juniperetum phoeniceae subass. rhamnetosum oleoides.

Contribuci��n al conocimiento melitopalinol��gico de Sierra Morena

Sc ha estudiado al microscopio ��ptico el sedimento de once muestras de miel de diversas localidades del este de Sierra Morena. Se pone de manifiesto que, en este ��rea, el n��ctar de flores es la principal fuenle de miel para Apis mellifera,siendo la mielada poco importante. Echium plantagineum, Lavandula stoechas y Eucalyptus camaldulensis son las principales fuentes de miel en este ��rea, en tanto que Cistus ladanifer, C. albidus, Olea europaea y Quercus sp. lo son de polen.

Acerca de la cariolog��a de algunas genisteas del centro-occidente espa��ol

En este trabajo se estudian, desde el punto de vista cariol��gico, nueve genisteas (Genista, Retama y Adenocarpus) en un total de trece poblaciones. Se confirma el n��mero cromos��mico de todas ellas, se��alando la existencia de poliploid��a secundaria en las diferentes subespecies de Adenocarpus consideradas.

Algunas plantas de los arenales de la cuenca del Duero

Se comentan 11 especies recogidas en los extensos arenales de la cuenca media del rio Duero. Destacan algunas netamente sabul��colas como Salix arenaria L., Phleum arenarium L. y Carex arenaria L.

Piornales y retamales meso y supramediterr��neos salmantinos y zamoranos

Se estudian las formaciones con dominio de leguminosas le��osas, de las provincias de Salamanca y Zamora ubicadas en los pisos bioclim��ticos meso- y supramediterr��neo, pertenecientes a la clase Cytisetea scopario-striati. Se aportan datos ecol��gicos, flor��sticos y fitosociol��gicos, a la vez que se conocen nuevos sintaxones para la ciencia.