174 A RESEARCH ON THE EUCALYPTS OF TASMANIA 



The tree collected by Gunn at Lake St. Clair and upon 

 which Bentham founded the variety elata, is just possibly 

 E. Delegatensis. 



The variety hy pericifolia of E . amygdalina recorded by 

 Bentham is found by us to belong to E . Risdoni. 



Mr. T. Stephens informs us that E . Eisdoui only grows 

 on mudstone formation — geologically classed as Upper 

 Palaeozoic, Permo-Carboniferous. 



Chemistry. 



Essential Oil. — The results obtained with the oil of 

 E. Risdoni are recorded in our work '' Research on the 

 Eucalypts " (p. 209). The yield of oil then obtained was 

 r35 per cent. ; saponification number for ester and free 

 acid = 27" 1; eucalyptol 64 per cent, in the fraction, and 

 95 per cent, distilled below 198^ C. It contained phel- 

 landrene, and was exceedingly rich in eucalyptol for a 

 phellandrene-bearing oil. 



To enable the ])resent research to be somewhat complete, 

 we obtained material for distillation of the reputed 

 E. Risdoni, var. elata, from Mt. Wellington, collected in 

 August, 1912. The results show the oil to be in agree- 

 ment with that of the ordinary form previously deter- 

 mined. 



We also received material for distillation of the so-called 

 E. amygdalina, var. hy pericifolia, collected by Mr. Irbv, 

 near Hobart, at the end of April, 1912, under the kind 

 direction of Mr. Rodway. This also gave results identical 

 with those of ?J . Risdoni, and as the botanical features 

 are also in agreement with that species, we consider it to 

 be E. Risdoni. The chief characteristics in the oil of 

 E . Risdoni are that it contains over 55 per cent, of euca- 

 lyptol ; a somewhat large amount of phellandrene ; belongs 

 to the '' peppermint " group, as it contains some piperi- 

 tone ; has a somewhat high saponification number by boil- 

 ing, and a low one by the cold saponification method ; 

 gives over 90 per cent, distilling below 195° C. ; and has 

 scarcely any objectionable volatile aldehydes. 



The crude oil of J'J . Risdoni (supposed variety elata) 

 from Mt. Wellington was lemon-yellow in colour, and 

 responded to all the tests and requirements recorded above. 

 Average yield of oil = 1-52 per cent. Specific gravity at 

 150 c. - 0-9061 ; rotation aj) - - 14' 1° ; refractive index 

 at 18° = 1-4679, and was soluble in 3 volumes 70 per cent. 



