Variation in adult morphology and volatile leaf oils was examined in five populations of the rare Eucalyptus yarraensis Maiden & Cambage sampled over the species’ natural range in Victoria. Thespecies shows little morphological variation, but there is clear geographicseparation of two chemical forms of leaf oil, with a high benzaldehyde form ineastern populations, and a high 1,8-cineole chemical form in westernpopulations. The occurrence of chemical forms may be related to environmentalparameters. In the absence of genetic data, the chemical variation in thespecies suggests that secure populations need to be protected to include thetwo different chemical types. There are some relatively secure westernpopulations, but representative eastern populations are usually small andvulnerable to local extinctions. If the genetic resources of this disjunctspecies are to be preserved, the species may need formal legislative protection.