Biologie, Ökologie und Vergesellschaftung von Verbascum densiflorum Bertol. (Großblütige Königskerze) unter besonderer Berücksichtigung Norddeutschlands
The ecology of Verbascum densiflorum, a widespread biennial archaeophyte, was investigated in Central Europe. The main focus was on the southern parts of North Germany, because during the last years its appearance has become more frequent in this region. In sandy summer warm areas there are often large stands of Verbascum densiflorum on fallow land and on road embankments mostly on lax soils often poor in humus. Whereas the large dominance stands often collapse after few years, Verbascum densiflorum is able to survive for a longer time on steep embankments where always open soil appears because of sliding and damages caused by dryness. The longest observed stand exists since 35 years. Verbascum densiflorum grows in communities of the alliances Dauco-Melilotion and Onopordion, whereas the majority of stands in northern Germany is found in Dauco-Melilotion. Verbascum densiflorum can no longer be seen as characteristic species of the alliance Onopordion but as a characteristic species of the order Onopordetalia. Because of its wide sociological and ecological amplitude it is not suitable to be a characteristic species of a specific Verbascum densiflorum association. Such association would only be of local importance. Nevertheless the high stands appearing in the last years are an interesting topic for investigations. Besides the syntaxonomic questions, the interesting phenomenon remains that an archaeophyte conquers new habitats and possibly changes its existing sociological attachments. The behaviour of Verbascum phlomoides, a related species which is sometimes associated with Verbascum densiflorum, is also discussed.