a genus of perennial herbs of the family Compositae.
There are more than 30 species of Arnica, most of which are found in North America. Some are found in Europe and Asia. In the USSR there are eight species. The best known is mountain tobacco (A. montana). It has a short, thick rhizome, is up to 60 cm high, and has a single involucrate head of yellow orange flowers. Mountain tobacco is found in Byelorussia, Lithuania, and the western Ukraine in forests and mountain meadows. As a rule, it grows in moist soils. In medicine an alcohol infusion made from the dried flower heads is used as a cholagogue and an antihemorrhagic (in uterine hemorrhaging). Mountain tobacco, A. foliosa, and A. chamissonis are cultivated as medicinal plants.