Abstract
The aim of this study was to identify the habitat requirements and host specificity of critically endangered species Thesium ebracteatum that is a root hemiparasite. We conducted a vegetation survey and tested whether some plant species occur significantly more often in plots with Thesium than expected, thereby representing potential hosts of hemiparasites.
To test whether the potential hosts are the species to which Thesium is physically attached we conducted excavating and sowing experiment. Such kind of experiment, however, could endanger performance of populations of rare species and that is why we used related common T. linophyllon for this experiment.
Thesium bavarum was added to our study as another rare species for comparison of results. Moreover we studied population performance in two populations of T. ebracteatum - Velenka in the Czech Republic and Schönwalde in Germany.