Common Ragweed (Ambrosia artemisiifolia) is the most widespread plant of the genus Ambrosia in North America. It is also known as Annual Ragweed, Bitterweed, Blackweed, Carrot Weed, Hay Fever Weed, Roman Wormwood, Stammerwort, Stickweed, Tassel Weed, Wild Tansy, and American Wormwood.