Prunella vulgaris, a species in the mint family.
Valeriana officinalis, a species in the valerian family.
Stachys, a genus of plants in the mint family, heal-all, self-heal, woundwort, betony, lamb's ears, hedgenettle.
Especially, Prunella vulgaris.
A small, herbaceous European plant with blue-violet flowers from any species of genus Prunella.