An increase in the atmospheric carbon dioxide (CO(2)) concentration results in a decrease in the number of leaf stomata. This relation is known both from historical observations of vegetation over the past 200 years and from experimental manipulations of microenvironments. Evidence from stomatal frequencies of fossil Quercus petraea leaves indicates that this relation can be applied as a bioindicator for changes in paleoatmospheric CO(2) concentrations during the last 10 million years. The data suggest that late Neogene CO(2) concentrations fluctuated between about 280 and 370 parts per million by volume.
Some 29 samples containing fruits and seeds were collected in three open cast mines in the lower Rhenish Basin. They all originate from Upper Miocene deposits. The samples were analysed for their fruit and seed contents and these are described shortly. Four new species: Erica palaeoarborea, Vaccinium miocenicurn, Rhynchospora tertiaria and Potamogeton extremitatus are formally described. The floras are interpreted ecologically using the ecological comparison table method and a reconstruction of the landscape is presented.
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