wolf's bane vs wolfsbane

wolf's bane and wolfsbane both are nouns.

Word	Noun	Adjective	Verb	Adverb
wolf's bane	Yes	No	No	No
wolfsbane	Yes	No	No	No

As nouns, wolf's bane and wolfsbane are synonyms defined as:

wolf's bane and wolfsbane: poisonous Eurasian perennial herb with broad rounded leaves and yellow flowers and fibrous rootstock

Other synonyms of wolf's bane include Aconitum lycoctonum, wolfbane.

wolf's bane (noun)	wolfsbane (noun)
poisonous Eurasian perennial herb with broad rounded leaves and yellow flowers and fibrous rootstock	poisonous Eurasian perennial herb with broad rounded leaves and yellow flowers and fibrous rootstock