Abstract
Commercial powdered samples of Verbascum flowers and slightly broken and powdered samples obtained from previously authenticated plant material (flowers of Verbascum thapsus L. subsp. thapsus) were examined by SEM. For the powdered drug, the most valuable diagnostic characters are the 3-colporoidate prolate pollen grains with reticulate exine and the co-occurrence of smooth branched and of warty-striated non-branched trichomes. Contamination of a commercial powdered sample of Verbascum flowers with plant material not belonging to a Verbascum species (most probably flowers of a Composite), was observed.