Marrubium (horehound or hoarhound) is a genus of about 40 species of flowering plants in the family Lamiaceae, native to temperate regions of Europe and Asia.
The genus name Marrubium derives from the Hebrew marrob or bitter juice. The common name horehound is of unknown origin, but with the first part 'hore' derived from "hoary", "hairy".
The species formerly classified as Marrubium nigrum (Black Horehound) is now placed in the genus Ballota.
Marrubium species are used as food plants by the larvae of some Lepidoptera species including Coleophora lineolea.
Source: Wikipedia, Wikispecies: All text is available under the terms of the GNU Free Documentation License