First discovery of flowering Wolffia arrhiza in Central Europe

摘要

Highlights?We describe the first record of floweringWolffia arrhizain Central Europe.?Presence of flowers is not a differentiator betweenW. arrhizaand alienW.species.?A former report about floweringW. arrhizain Europe was false due to mistranslation.Flowering ofWolffia arrhizawas discovered for the first time in Germany. This record is also the first observation of flowers in this species for Central Europe. The locality is described and the plants are photographically documented. Hitherto, floweringW. arrhizahad never been reported for the whole of Europe, with the only exception being two records from the 1980s in Istria (former Yugoslavia, South-East Europe). A further report about alleged flowering plants in the northern forelands of the Caucasus turned out to be erroneous, due to mistranslation and the wrong citation of an original publication from 1957 in Slovak language.