Tansy (Tanacetum vulgare) is sometimes called Golden Buttons due to its flat topped flower heads.  Its strongly aromatic leaves used to be used for flavouring omelettes and for making traditional Tansy Cake when imported spices were very expensive.  In folk medicine a concoction would be used to treat various problems including intestinal worms, as a mouthwash or a cure for insomnia  but its greatest importance was in using leaves to repel flies or mice around the house.  However it is now known to be toxic if ingested.