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Flora Europaea, Vol. 1. Lycopodiaceae to Platanaceae (2nd edn).
Journal of Ecology
... Para la fl ora ibérica, existe un representante espontáneo, C. violacea L., distribuido por el W y S de la Península Ibérica y el Norte de África (Marcos-Samaniego & Paiva, 1993). También, dentro de la fl ora europea, además de la citada especie, crece C. ornithopodioides L., con distribución por el cuadrante SE del continente (Chater, 1964). Dentro de este grupo de plantas, recientemente han sido hallados dentro de los viveros del Centro para la Investigación y la Experimentación Forestal de la Generalitat Valenciana (CIEF) destinados a la producción de planta autóctona, varios ejemplares de C. viscosa L., planta hasta la fecha desconocida para la fl ora ibérica (cf. ...
... as, recientemente han sido hallados dentro de los viveros del Centro para la Investigación y la Experimentación Forestal de la Generalitat Valenciana (CIEF) destinados a la producción de planta autóctona, varios ejemplares de C. viscosa L., planta hasta la fecha desconocida para la fl ora ibérica (cf. Samaniego & Paiva, 1993) y también europea (cf. Chater, 1964, Daise, 2009). Su área de distribución natural recoge al menos los territorios tropicales y subtropicales del Viejo Mundo, desde África hasta el Sudeste Asiático (Apcd, 2010), aunque todavía no se conoce con detalle su origen preciso, ya que en determinados países supuestamente encuadrados dentro de su área de distribución natural se co ...
Polyploidy is one of the major forces of plant evolution and widespread mixed-ploidy species offer an opportunity to evaluate its significance. We therefore selected the cosmopolitan species Urtica dioica (stinging nettle), examined its cytogeography and pattern of absolute genome size, and assessed correlations with bioclimatic and ecogeographic data (latitude, longitude, elevation). We evaluated variation in ploidy level using an extensive dataset of 7012 samples from 1317 populations covering most of the species’ distribution area. The widespread tetraploid cytotype (87%) was strongly prevalent over diploids (13%). A subsequent analysis of absolute genome size proved a uniform Cx-value of core U. dioica (except for U. d. subsp. cypria) whereas other closely related species, namely U. bianorii, U. kioviensis and U. simensis, differed significantly. We detected a positive correlation between relative genome size and longitude and latitude in the complete dataset of European populations and a positive correlation between relative genome size and longitude in a reduced dataset of diploid accessions (the complete dataset of diploids excluding U. d. subsp. kurdistanica). In addition, our data indicate an affinity of most diploids to natural and near-natural habitats and that the tetraploid cytotype and a small part of diploids (population from the Po river basin in northern Italy) tend to inhabit synanthropic sites. To sum up, the pattern of ploidy variation revealed by our study is in many aspects unique to the stinging nettle, being most likely first of all driven by the greater ecological plasticity and invasiveness of the tetraploid cytotype.
Aim To obtain palaeobotanical evidence enabling evaluation of the viability of the hypothesis that the ‘oriental’ element of the Balkan flora reached south‐east Europe from Turkey prior to the Holocene, probably via the Thracian Plain during a late Quaternary glacial stage but no later than the late Weichselian.
Location Ezero wetland, northern Thracian Plain, Bulgaria.
Methods We undertook analyses of pollen and microspores, plant macrofossils, wood fragments and molluscs recovered from sediments deposited in the Ezero wetland during the late Weichselian and Weichselian late‐glacial. Sediment chronology was determined using radiocarbon age estimates.
Results Six metres of sediments were recovered from the basin, of which the lower 3 m, extending from c . 15,450 cal yr bp to the early Allerød, was analysed. A major hiatus occurred after c . 13,900 cal yr bp , the overlying sediments being of late Holocene age. Palaeobotanical evidence indicates predominantly open vegetation during the Weichselian late‐glacial, although macrofossil remains of woody taxa demonstrate the local presence of patches of wooded steppe and gallery forest. Changes in the composition of the steppe vegetation, and in the nature of the sediments deposited in the basin, indicate changes in climatic conditions, especially in the hydrological regime and in the moisture available to vegetation. After an initially relatively moister phase, the final centuries of the late Weichselian were drier, as was a short interval that may correlate with the Older Dryas. Moister conditions characterize intervals corresponding to the Bølling and Allerød sub‐units of the Weichselian late‐glacial interstadial. Although the pollen evidence is thus consistent with that from previous studies of this period in south‐east Europe and south‐west Asia, indicating predominantly open steppe vegetation, the macrofossil evidence indicates the persistent local presence of woody taxa. The woody taxa recorded include Celtis tournefortii ‐type and Juniperus cf. J. excelsa , two taxa today characteristic of the wooded steppes of Anatolia and members of the ‘oriental’ element of the southern Balkan flora, as well as Rosaceae Subfams. Maloideae and Prunoideae, Alnus and Fraxinus .
Main conclusions The late Weichselian vegetation of the northern Thracian Plain included patches of wooded steppe that supported members of the ‘oriental’ element of the modern Balkan flora. The presence of such taxa renders viable the hypothesis that they could have reached south‐east Europe from Turkey via the Thracian Plain during glacial times. Such hypotheses in historical biogeography can be evaluated critically using the evidence obtained from plant macrofossil analyses in combination with that from pollen analysis.
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