bitterroot

Short definition from Wiktionary

Noun

1. 1
   Lewisia rediviva, a small, low, pink flower with a yellow center.
2. 2
   Apocynum androsaemifolium (fly-trap dogbane).
3. 3
   Gentiana lutea (great yellow gentian, bitterwort)

Adjective

1. 1
   Having bitter roots.