abstract the leaf oils of eucalyptus chartaboma nicolle, eucalyptus miniata cunn. shauer and e. gigantangion l. johnson et k. hill have been analyzed by a combination of gc and gc/ms. eucalyptus chartaboma has been found to exist as two chemotypes that are determined by the number of aryl ketones contained in the leaf oil. chemotype 1 contained isobaeckeol (1-(6-hydroxy-2, 4-dimethoxy-3-methylphenyl)-2-methylpropan-1-one) and homoisobaeckeol (1-(6-hydroxy-2, 4-dimethoxy-3-methylphenyl)-2-methylbutan-1-one), each accounting for approximately 25% of the oil. chemotype 2 contained nine aryl ketones: apodophyllone (1-(2,4,6-trimethoxy-3, 5-dimethylphenyl)-2-methylpropan-1-one), isotorquatone (1-(2,4,6-trimethoxy-3,5-dimethylphenyl)-2-methylbutan-1-one), torquatone (1-(2,4,6-trimethoxy-3,5-dimethylphenyl)-3-methylbutan-1-one), chartabomone (1-(6-hydroxy-2,4-dimethoxy-3,5-dimethylphenyl)-2-methylbutan-1-one), isobaeckeol, miniatone (1-(6-hydroxy-2,4-dimethoxy-3,5-dimethylphenyl)-3-methyl-butan-1-one), baeckeol methyl ether, homoisobaeckeol and homobaeckeol methyl ether, which together accounted for approximately 50% of the oil. in both cases, the remainder of the oil consisted of terpenes, with -pinene being by far the major component. eucalyptus miniata contained only one chemotype, which contained all nine of the above aryl ketones in similar proportions to those in chemotype 2 of e. chartaboma. e. gigantangion did not contain any aryl ketones in its leaf oil, which was composed entirely of terpenes, with -pinene (45%), limonene (5%), -terpineol (8%) and borneol (5%) being the principal components. key word index: eucalyptus miniata eucalyptus gigantangion eucalyptus chartaboma myrtaceaeessential oil compositionisobaeckeolhomoisobaekeoltorquatoneisotorquatonebaekeol methyl etherhomobaeckeol methyl etherapodophyllone-pinene