Contribución al conocimiento cariológico del género Cenntaurea L. (Asteraceae) en la Península Ibérica

Contribución al conocimiento cariológico del género Centaurea L. (Asteraceae) en la Península Ibérica. Se da a conocer el número cromosómico de 22 táxones de Centaurea L. sect.Centaurea. En particular, se han estudiado 18 táxones del grupo de C. paniculata L., de los que C.paniculata subsp. exilis Arènes, C. paniculata subsp. geresensis Arènes, C. coutinhoi Franco, C.kheilii (Pau) Pau, C. limbata var. insularis Pau, C. castellanoides subsp. talaverae E. López & Devesa, C. cordubensis Font Quer, C. bethurica E. López & Devesa y C. schousboei Lange lo han sido por vez primera. Del grupo de C. alba L. se han estudiado 4 táxones, siendo nuevos los recuentos de C.costae Willk. var. costae y C. costae var. maluqueri Font Quer. En ambos grupos el número básico encontrado ha sido x = 9. El número diploide 2n = 18 es el más frecuente mientras que el nivel tetraploide 2n = 36(4x) sólo se ha detectado en C. aristata Hoffmanns. & Link, C. cordubensis Font Quer y C. schousboei Lange.A contribution to the karyological knowledge of the genus Centaurea L. (Asteraceae) in the Iberian Peninsula. A karyological study of 22 taxa of genus Centaurea L. sect. Centaurea is reported. Within C. paniculata L. group we have studied 18 taxa and the reports for some of them are given for the first time: C. paniculata subsp. exilis Arènes, C. paniculata subsp. geresensis Arènes, C. coutinhoi Franco, C. kheilii (Pau) Pau, C. limbata var. insularis Pau, C. castellanoides subsp.talaverae E. López & Devesa, C. cordubensis Font Quer, C. bethurica E. López & Devesa and C.schousboei Lange. Within C. alba L. group we have studied the chromosome number of 4 taxa, but only C. costae Willk. var. costae y C. costae var. maluqueri Font Quer are studied for the first time.In both groups we have found the basic number x = 9. Diploid number 2n = 18 is the most frequent whereas tetraploid level 2n = 36(4x) has been found only in C. aristata Hoffmanns. & Link, C.cordubensis Font Quer and C. schousboei Lang

A contribution to the karyological knowledge of the genus Centaurea L. (Asteraceae) in the Iberian Peninsula.

A contribution to the karyological knowledge of the genus Centaurea L. (Asteraceae) in the Iberian Peninsula. A karyological study of 22 taxa of genus Centaurea L. sect. Centaurea is reported. Within C. paniculata L. group we have studied 18 taxa and the reports for some of them are given for the first time: C. paniculata subsp. exilis Arènes, C. paniculata subsp. geresensis Arènes, C. coutinhoi Franco, C. kheilii (Pau) Pau, C. limbata var. insularis Pau, C. castellanoides subsp. talaverae E. López & Devesa, C. cordubensis Font Quer, C. bethurica E. López & Devesa and C. schousboei Lange. Within C. alba L. group we have studied the chromosome number of 4 taxa, but only C. costae Willk. var. costae y C. costae var. maluqueri Font Quer are studied for the first time. In both groups we have found the basic number x = 9. Diploid number 2n = 18 is the most frequent whereas tetraploid level 2n = 36(4x) has been found only in C. aristata Hoffmanns. & Link, C. cordubensis Font Quer and C. schousboei Lange.Contribución al conocimiento cariológico del género Centaurea L. (Asteraceae) en la Península Ibérica. Se da a conocer el número cromosómico de 22 táxones de Centaurea L. sect. Centaurea. En particular, se han estudiado 18 táxones del grupo de C. paniculata L., de los que C. paniculata subsp. exilis Arènes, C. paniculata subsp. geresensis Arènes, C. coutinhoi Franco, C. kheilii (Pau) Pau, C. limbata var. insularis Pau, C. castellanoides subsp. talaverae E. López & Devesa, C. cordubensis Font Quer, C. bethurica E. López & Devesa y C. schousboei Lange lo han sido por vez primera. Del grupo de C. alba L. se han estudiado 4 táxones, siendo nuevos los recuentos de C. costae Willk. var. costae y C. costae var. maluqueri Font Quer. En ambos grupos el número básico encontrado ha sido x = 9. El número diploide 2n = 18 es el más frecuente mientras que el nivel tetraploide 2n = 36(4x) sólo se ha detectado en C. aristata Hoffmanns. & Link, C. cordubensis Font Quer y C. schousboei Lange

The explosive radiation of Cheirolophus (Asteraceae, Cardueae) in Macaronesia

Considered a biodiversity hotspot, the Canary Islands have been the key subjects of numerous evolutionary studies concerning a large variety of organisms. The genus Cheirolophus (Asteraceae) represents one of the largest plant radiations in the Canarian archipelago. In contrast, only a few species occur in the Mediterranean region, the putative ancestral area of the genus. Here, our main aim was to reconstruct the phylogenetic and biogeographic history of Cheirolophus with special focus on explaining the origin of the large Canarian radiation. Results: We found significant incongruence in phylogenetic relationships between nuclear and plastid markers. Each dataset provided resolution at different levels in Cheirolophus: the nuclear markers resolved the backbone of the phylogeny while the plastid data provided better resolution within the Canarian clade. The origin of Cheirolophus was dated in the Mid-Late Miocene, followed by rapid diversification into the three main Mediterranean lineages and the Macaronesian clade. A decrease in diversification rates was inferred at the end of the Miocene, with a new increase in the Late Pliocene concurrent with the onset of the Mediterranean climate. Diversification within the Macaronesian clade started in the Early-Mid Pleistocene, with unusually high speciation rates giving rise to the extant insular diversity. Conclusions: Climate-driven diversification likely explains the early evolutionary history of Cheirolophus in the Mediterranean region. It appears that the exceptionally high diversification rate in the Canarian clade was mainly driven by allopatric speciation (including intra-and interisland diversification). Several intrinsic (e.g. breeding system, polyploid origin, seed dispersal syndrome) and extrinsic (e.g. fragmented landscape, isolated habitats, climatic and geological changes) factors probably contributed to the progressive differentiation of populations resulting in numerous microendemisms. Finally, hybridization events and emerging ecological adaptation may have also reinforced the diversification process

A contribution to the karyological knowledge of the genus Centaurea L. (Asteraceae) in the Iberian Peninsula. Sect. Seridia (Juss.) DC.

Se da a conocer el número cromosómico de 10 taxones del género Centaurea pertenecientes a la sección Seridia (Juss.) DC. presentes en la Península Ibérica. En el caso de Centaurea lusitanica var. crassifolia P. Silva, C. aspera subsp. stenophylla (Dufour) Nyman y C. barrasii Pau se trata, al parecer, del primer recuento. El número diploide 2n = 22 es el más frecuente en el grupo estudiado, mientras que el nivel tetraploide 2n = 44 sólo se ha detectado en C. seridis L. y C. sphaerocephala L.A karyological study of taxa of genus Centaurea L. sect. Seridia (Juss.) DC. in the Iberian Peninsula is reported. We have studied 10 taxa and the reports for 3 of them are given for the first time: Centaurea lusitanica var. crassifolia P. Silva, C. aspera subsp. stenophylla (Dufour) Nyman and C. barrasii Pau. Diploid number 2n = 22 is the most frequent whereas tetraploid level 2n = 44 has been found only in C. seridis L. and C. sphaerocephala L

Ambiguous Dependence Of Minimal Plant Generation Time On Nuclear DNA Content

AMBIGUOUS DEPENDENCE OF MINIMAL PLANT GENERATION TIME ON NUCLEAR DNA CONTENT Victor B. Ivanov The minimum generation time (MGT) of plant development was suggested to depend on nuclear DNA content, which varies in plants over wide limits1. In ephemeral species with the shortest MGT, the average C values were significantly lower than in annual species, whereas the average C values in annual species were lower than those in perennial plants. However, nobody has paid attention to the ratio of annual to perennial species number as a function of C values. Here I show that with increasing C the ratio of annual to perennial species increases to C values equal to 7-8 pg (monocots) and 6-7 pg (eudicots) and then decreases and that the fraction of annuals is abundant not at the lowest, but at some higher C levels. Hence, C value increase exerts an ambiguous effect on MGT. The C value is not the only factor, which determines the duration of the plant development. Nevertheless, the nuclear DNA content exerts a pronounced effect on MGT together with other diverse factors affecting the rate of plant development, especially at higher C values

Revisión taxonómica del complejo Centaurea alba L. (Asteraceae) en la Península Ibérica

Taxonomic revision of the Centaurea alba L. complex (Asteraceae) in the Iberian Peninsula.- A taxonomic revision of the Centaurea alba L. complex (Centaurea L. sect. Centaurea) in the Iberian Peninsula is presented, which is represented by two species, C. alba and C. costae Willk. Three subspecies of C. alba with reasonably well-defined areas are recognized: C. alba subsp. alba, with three varieties –alba, macrocephala Pau and latronum (Pau) E. López & Devesa-, C. alba subsp. aristifera (Pau) E. López & Devesa and C. alba subsp. tartesiana Talavera, two of them are proposed as new nomenclatural combinations. Centaurea costae is segregated from C. alba and three varieties are recognized: costae, montsicciana Pau & Font Quer and maluqueri Font Quer. In the case of C. alba var. latronum, C. alba var. macrocephala and C. alba subsp. aristifera, the chromosome number was also studied (2n = 18).Revisión taxonómica del complejo Centaurea alba L. (Asteraceae) en la Península Ibérica.- Se efectúa la revisión taxonómica del complejo de Centaurea alba L. (Centaurea L. sect. Centaurea) en la Península Ibérica, representado por dos especies, C. alba y C. costae Willk. Para C. alba se reconocen tres subespecies con áreas bien definidas: C. alba subsp. alba, con tres variedades –alba, macrocephala Pau y latronum (Pau) E. López & Devesa-, C. alba subsp. aristifera (Pau) E. López & Devesa y C. alba subsp. tartesiana Talavera, proponiéndose dos nuevas combinaciones. Se segrega Centaurea costae de C. alba, y se reconocen para ella tres variedades: costae, montsicciana Pau & Font Quer y maluqueri Font Quer. En el caso de C. alba var. latronum, C. alba var. macrocephala y C. alba subsp. aristifera se ha estudiado además el número cromosómico (2n = 18)

Pollen signals of ground flora in managed woodlands

This paper explores the vegetation signals contained in the non-arboreal pollen and spore (NAPS) components of pollen assemblages from Tauber traps placed in woodlands subject to rotational cutting (coppicing) in lowland England. Sets of three Tauber traps were placed in compartments of different ages at multiple locations within each woodland for 1 year, and pollen assemblages recorded along with a vegetation survey using a modified pin-frame method in an area of 10 m radius around each trap array. Cluster analysis suggests that, as expected, the ground layer vegetation broadly reflects the different environmental conditions in the three woods, with the main subdivisions within woods apparently driven by changes in ground cover between the early and late stages of the coppice cycle. Non-arboreal pollen and spores (NAPS) assemblages group according to woodland of origin, with subdivisions which relate to pollen abundance but lack a simple relationship with years since cutting. Indices of Association between NAPS records and plant presence in the area around each array were calculated using presence–absence data for multiple distances of vegetation survey. All values tend towards an asymptote, which is interpreted as implying an effective source area for the single taxon presence–absence indicator values of ground flora taxa in coppiced woodlands on the order of a 10 m radius. Only four taxa, Poaceae, Ranunculus acris-type, Cyperaceae, and Scilla-type, have an Index of Association (A) greater than 0.5, implying that the presence of pollen can be interpreted in terms of the local presence of the relevant plant taxon with some confidence. Estimates of Pollen Productivity relative to Poaceae are presented for five taxa: Apiaceae, Asteraceae (Cardueae), Cyperaceae, Mercurialis perennis, and Scilla-type. Years since cutting does affect the ground vegetation and NAPS assemblage trapped in these woods, but that the effect is more clearly seen at an assemblage level in the vegetation than in the pollen assemblages. The interpretative significance of NAPS taxa does not seem to be in providing information about the local conditions around the sampling point, but in reflecting the ground flora of the wider woodland

On the classification of CarthamusCarduncellus complex (Asteraceae, CardueaeCentaureinae) and its treatment in Flora iberica

Después de analizar las alternativas de clasificación del complejo Carthamus-Carduncellus que son compatibles con los resultados de los análisis moleculares, se propone volver a la clasificación en dos géneros de Hanelt (1963) modificada por la inclusión de Carthamus sect. Thamnacanthus (DC.) Hanelt en Carduncellus Adans.; se incluye Femeniasia Susanna, no estudiada por Hanelt, en Carduncellus. Se hacen las nuevas combinaciones Carduncellus rhiphaeus (Font Quer & Pau) G. López, Carduncellus balearicus (J. J. Rodr.) G. López, Carduncellus sect. Thamnacanthus (DC.) G. López y C. hispanicus subsp. intercedens (Degen & Hervier) G. López. Se describe la nueva serie Carduncellus ser. Fruticosi G. López, y las variedades C. monspelliensium var. almeriensis G. López & var. valentinus G. López. Carthamus L., tal como aquí se delimita, esta formado únicamente por plantas anuales que tienen las cipselas externas epaposas (muy raramente con vilano), y el resto con un vilano persistente formado por cerdas anchas, paleáceas, linear-lanceoladas o espatuladas. Carduncellus Adans., por plantas perennes, herbáceas o leñosas en las que todas las cipselas tienen vilano (muy raramente pueden ser epaposas), siendo el vilano persistente o frecuentemente caduco, formado por cerdas estrechamente lineares. Carthamus es del Mediterráneo oriental y O. de Asia , y Carduncellus Adans. está centrado biogeográficamente en el Mediterráneo occidental

Contribución al conocimiento de paisaje holoceno de la provincia de Soria: Análisis palinológico en el yacimiento arqueológico de Parpantique

This paper presents the palynological analyses carried out on six samples which proceed from excavations at the Parpantique site (Balluncar, Soria, Spain). This site includes archaeological levels which range from Bronze to Middle Age. The palynological record shows a strong anthropogenic impact on the vegetal assemblages from 3730 years BP. Moreover the development of the cereal culture during the Medieval age is also recorded

Contribución de la palinología a la reconstrucción del medio en la Prehistoria andaluza: la Cueva del Nacimiento (Pontones, Jaén)

Se presenta en este artículo la interpretación del análisis polinico del yacimiento neolítico andaluz de la Cueva del Nacimiento, y como dichos resultados proporcionan un mejor conocimiento de aspectos económicos , culturales y de medio ambiente durante el Neolítico , así como la importancia de reconstrucción de los modos de vida de los grupos humanos y su influencia en el paisaje .This paper presents t he results of pollen ana lysis :from a southern Spaniser Neolithic site , the "Cueva del Nacimiento" , in Jaen province . These results provide a better understanding of aspects of the economy , cultur e and envi ronment during t he Neoli thic period . Furthermore , the paper demons t rates thc importance of such palaeobotanical evidence f or reconst ruction of the way of li fe of human groups and their influence on t he natural surrounding