Summary: This report has been illustrated and analyzed the results of the tests carried out on polínicos lacustrine sediment on the lake bottom of Stracciacappa, lake of volcanic origin which was artificially drying during the first half of the nineteenth century. These studies were partially completed with the analysis carried out on some samples of sediment from the bottom of adjacent Lake Martignano. This study is part of the field of paleoenvironmental studies to Palaeobotany and Palynology laboratory at the University of "La Sapienza", Created and directed for many years by Professor Mary Follieri, has done for over 20 years on the volcanic lakes Lazio (Central Italy). The sequence of sedimentary basins of the crater lake of Lazio are therefore excellent means for studies paleolimnilogía. The Lazio due to the great development of Quaternary volcanism, can be regarded as one of the regions of greatest interest to paleoenvironmental studies paleopalinológicos and of the Italian peninsula and much of the Mediterranean region, it is enough to observe that the studies on the lakes craters of Lazio have provided sequences polínicas longest of Italy and among the longest in Europe, such as the Valle di Castiglione (250,000 years; Follieri et al.,
1988), Lagaccione (100,000 years; Magri, 1999) and Lake di Vico (90,000 years; Magri, Sadori, 1999). The polínicos analysis of the sediments of Stracciacappa have helped reconstruct the history of vegetation in the last 60,000 years or so. This sequence Stracciacappa can be considered among the largest in Italy and Europe. Samples of Stracciacappa that have provided useful results are 136. Of these teachers, only 20 contain percentages of tree pollen (AP) higher than 50% and 116 samples with more than 50% of pollen from plants not tree (NAB). Only at the top of the sequence (age estimated 12,100 - 7,200 BP) plant tree pollen (AP) becomes dominant values reached percentages exceed 90% indicating the presence of a fully developed forest vegetation. Various expansions forest, more modest entity, are also observable in the rest of the stream. The Area Stra - 2 (age estimated 41,100 - 12,100 BP), more homogeneous, presents obvious characteristics estépicas. The sequence of Lago di Martignano shows, by contrast, a rather homogeneous vegetation dominated by tree taxa and in particular the Quercus either caducifilios or evergreen, which are accompanied by a discrete number other trees. The study of the sequence of Starcciacappa has provided elements organices for the reconstruction of the history of vegetation, flora and the climate in central Italy, in the final part of the Quaternary in particular has made a major contribution pair wing characterization bioestratigráfica the last pleniglacial. It has been proved of fundamental importance for understanding the changes in vegetation that have occurred in the late Pleniglacial and can be viewed as a sequence of reference for caracterizaicón bioestrateigráfica this period in central Italy. In fact, pollen is the sequence in which they are best forest identifiable episodes that characterize the Pleniglacial in central Italy. The seven major swings pleniglaciales angiosperm tree, clearly observable in Stracciacappa and recognizable in the sequence Valle di Castiglione, Lagaccione and Lago di Vico, has been referred to as "Complesso Laziale (Follieri et al., 1998). The study of sediment Stracciacappa has allowed also draw variations in the areas of distribution of different taxa forest and non-forest and rebuild its history as in the case of Zelkova and Spruce.
