9-Meth­oxy-6a,11a-dimethyl-6a,11a-dihydro-6H-1-benzofuro[3,2-c]chromen-3-ol from Dalbergia oliveri

The title compound, commonly known as (+)-(6aS,11aS)-medicarpin, C16H14O4, was isolated from Dalbergia oliveri and displays a rigid mol­ecule consisting of four fused rings. The benzofuran system is inclined at an angle of 76.49 (2)° with respect to the chroman unit. The compound exists as a polymeric chain arising from inter­molecular O—H⋯O bonding