A sesquiterpene aldehyde, (−)-lepidozenal, having a novel trans-fused bicyclo[8.1.0]undecane carbon skeleton has been isolated from the liverwort Lepidozia vitvea, and its structure and absolute configuration have been shown to be (6S,7R)-lepidoza-1(10)E,4E-dien-14-al, on the basis of the chemical and spectral evidence.