A new epoxy-trinoreudesmane sesquiterpene, aS,5R,8aS)-trans-4,8a-dimet
hyl-4a,5-epoxy-decalin, was isolated from the liverwort Lophocolea bid
entata collected in northern Germany. The structure of this compound w
as elucidated by means of spectroscopic methods and by independent syn
thesis. The configuration was proved by enantioselective gas chromatog
raphy. The previously described olefinic precursor was also identified
as a constituent.