About 160, see text Tanacetum is a genus of about 160 species of flowering plants in the aster family, Asteraceae, native to many regions of the Northern Hemisphere.

[6] The generic name Tanacetum means 'immortality' in Botanical Latin, since tansy was once placed between the burial sheets of the dead to repel vermin.

They vary in form, with one or more branching stems growing erect or prostrate, usually from rhizomes.

The flower has layers of distinct phyllaries around its base and may be flat to hemispheric in shape.

Some species have ray florets in shades of yellow, or white with yellowish bases.