Tanacetum is a genus of about 160 species of flowering plants in the aster family, Asteraceae, native to many regions of the Northern Hemisphere. They are known commonly as tansies. The name tansy can refer specifically to Tanacetum vulgare, which may be called the common tansy or garden tansy for clarity. Other familiar species include costmary (T. balsamita) and feverfew (T. parthenium).