(+)-hanegoketrial (5), have been isolated from the methanol extract of Plagiochilasemidecurrens together with the related enantiomeric sesquiterpenoids (12)–(15a). The structures and absolute configurations have been determined on the basis of chemical and spectroscopic evidence and are coincident with the result obtained by X-ray analysis of (+)-ovalifolienalone (3). The biological activity is also