Assertion: alder's bark | /r/MadeOf | tannins
Facets:
Source sentences:
text: The bark contains tannins (about 16%), taraxerol (a pentacyclic triterpenoid which is oleanan-3-ol lacking the methyl group at position 14), lupeol (a pentacyclic triterpenoid in which the hydrogen at the 3beta position is substituted by a hydroxy group), and minerals.