Variation in the morphology and volatile leaf oils of Eucalyptus yarraensis (Myrtaceae), a disjunct rare species in Victoria

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. The species shows little morphological variation, bur there is clear geographic separation of two chemical forms of leaf oil, with a high benzaldehyde form in eastern populations, and a high 1,8-cineole chemical form in western populations. The occurrence of chemical forms may be related to environmental parameters. Tn the absence of genetic data, the chemical variation in the species suggests that secure populations need to be protected to include the two different chemical types. There are some relatively secure western populations, but representative eastern populations are usually small and vulnerable to local extinctions. If the genetic resources of this disjunct species are to be preserved, the species may need formal legislative protection.