"As for monkshood and wolfsbane, they are the same plant, which also goes by the name of aconite. Well? Why aren't you all copying that down?"
-- Severus Snape in First Year Potions class (PS8)
Wolfsbane, also known as monkshood and aconite, is a plant used in potion-making. The plant is highly poisonous and must be handled with extreme care. Wolfsbane can be found in the book One Thousand Magical Herbs and Fungi (Pm:SB).
Potions Connection
Wolfsbane is an ingredient in the Wideye Potion (also called the Awakening Potion), as listed in Magical Drafts and Potions (Pm:SB).
Commentary
Etymology
The Greek name lycotonum, which translates literally to "wolf's bane", is thought to indicate the use of its juice to poison arrows or baits used to kill wolves (Wikipedia).
Notes
According to the "Harry Potter and the Philosopher's Stone video game" for the GameBoy Color, wolfsbane is an ingredient in the Wolfbane Potion.