Assertion: willow's bark | /r/MadeOf | salicin
Facets:
Source sentences:
text: However, people also use willow species for timber, and some species' bark contains salicin, which is turned into salicylic acid, the chemical from which aspirin is drawn.
text: The bark of white willow contains salicin, which is a chemical similar to aspirin (acetylsalicylic acid).