"ragwort." YourDictionary, n.d. Web. 20 September 2018. <http://www.yourdictionary.com/ragwort>.
ragwort. (n.d.). Retrieved September 20th, 2018, from http://www.yourdictionary.com/ragwort
Any of various plants in the composite family, chiefly of the genera Senecio and Packera, having yellow flower heads. S. jacobaea, a European species poisonous to livestock, is widely naturalized in North America and elsewhere.