Ragwort

Ragwort (Jacobaea vulgaris, syn. Senecio jacobaea) is a very common wild flower in the family Asteraceae that is native to northern Eurasia, usually in dry, open places, and has also been widely distributed as a weed elsewhere.
Alternative names include Cushag (Isle of Man), Buachalán Buí (Ireland) or Benweed, Tansy Ragwort, St. James-wort, Ragweed, Stinking Nanny/Ninny/Willy, Staggerwort, Dog Standard, Cankerwort, Stammerwort and Mare's Fart. In the western US it is generally known as "Tansy Ragwort", or even more confusingly "Tansy", though its resemblance to the true tansy is superficial at best. This is a potentially dangerous misuse of names, since the true tansy has been used for culinary purposes.