THE TITLE COMPOUND [SYSTEMATIC NAME: (9-meth-oxy-3,5-dimethyl-5,6-dihydro-naphtho-[2,3-b]furan-4-yl)methyl 2-meth-yl-but-2-enoate], C(21)H(24)O(4), was isolated from matarique, or Psacalium peltatum (Kunth). The structure is almost planar. The angelo-yloxy group makes an angle of 62.08 (2)° with the furan-oeremophilane skeleton. The carbonyl O atom is disordered between two positions with a 76:24 ratio. The mol-ecules in the crystal are joined by very weak C-H-O inter-actions in the ac plane.