Bitterweed

noun

1. A name given to American species of ragweed, Ambrosia artemisiæfolia and A. trifida.
2. A species of Ambrosia (Ambrosia artemisiæfolia); Roman worm wood.
3. Any plant in the genus Ambrosia, especially Ambrosia artemisiifolia.
4. The plant Artemisia trifida.
5. The plant Helenium amarum.