In this thesis the general distribution ranges of 1225 rare and endangered vascular plants species of the german flora were investigated in order to build a biogeographical database for conservation value assessment, which can be considered as the preliminary stage to definite conservation priority lists. Several evaluation-relevant features of the species and their distribution ranges are presented and their selection and scaling are described and justified. Here, biogeographical parameters for stock assessment and evaluation of threat are getting clearly defined and discussed in such detailed manner for the first time. The criteria consulted are the floristic-chronological naturalization status in Germany, the taxonomic distinctiveness of the species, the chorological character of the range section in Germany, the size of the total distribution range, the frequency and abundance of the species in their main areas, the proportion of the German occurrences in the general distribution range, the population development in the total area and the global and international imperilement of the species. Declining, indigenous and taxonomically distinct species with small and sparsely populated total ranges, which are endemics or near endemics to Germany were considered to be most important. From that plant-geographical view, species of lowest concern are those, which occur frequently in very large ranges, reaching Germany only marginally and behave as strongly increasing invasive species. Fundamental for an objective and comprehensible evaluation as well as for further analysis steps is the numeric classification and coding of the obtained range features. Therefore numeric conservation values are assigned to the classified features. One possible subsequent treatment of the raised data is the determination of the global biogeographical responsibility of Germany for the world-wide conservation of plant species currently under threat in Germany. In the result section of the study four data complexes are given, which present the results of biogeographically oriented analysis and evaluations of vascular plant species of the German Red List. The last part of the study deals with statistical analysis and discussions of the obtained feature distributions and the resulting surveys.