aconite; monkshood; wolfsbane

Definition 
Aconite (Aconitumnapellus) is a deadly poisonous plant, also known as wolfsbane and monkshood. Aconite itself derives from an ancient Greek word meaning "wolfsbane." Ancient legend says the showy perennial herb is of the buttercup family and that it became poisonous from the foam that dropped from the mouth of the monstrous hound Cerberus, who guarded the gates of Hell, when Hercules dragged him up from the nether regions. Some authorities say aconite derives from the Greek akon, "dart," because it was once used as an arrow poison. See also wolfsbane.