A remarkable number of plant species, tolerant against heavy metals, could be found in partly large populations on the area of Neudiepenbock III, a former ore mine in Mülheim an der Ruhr-Selbeck, that closed down about a hundred years ago. Amoung these plants, the bryophytes Scopelophila cataractae and Pohlia flexuosa as well as the lichens Acarospora rufescens, Stereocaulon vesuvianum var. nodulosum and Vezdaea rheocarpa were not known to be present in the westem part of the Ruhr area up to now. The occurrence of these species is relevant with concem to Northrhine-Westfalia (NRW) and Germany, e.g. Acarospora rufescens is possibly new for NRW and Vezdaea rheocarpa is only known from two other localities in the whole of Germany. In this text, the biogeographical importance, the relevance to the biodiversity of the agglomeration Ruhr area as well as the endangerment of the taxa is discussed. Keywords: ore mining, heavy metal tolerant plants, zinc flora, lichens, bryophytes, Ruhr area.