LEAF VENATION AND CHEMICAL CONSTITUENTS OF EUCALYPTS. 117 



and E. robusta; of the "Blue Gum" E. saligna, of E. tesselaris, 

 and a few others. 



This particular venation is of importance because it is also 

 generally characteristic of the Angophoras. The chemical evidence 

 shows that the connection with the Angophoras is directly associ- 

 ated with those Eucalypts that have this particular venation in 

 their leaves. 



This venation, which is best seen in a photograph, appears to be 

 indicative of a predominance of pinene in the oil, because this 

 terpene is an important constituent in all those species that show 

 this venation, while phellandrene is quite absent, and in the oil 

 that we distilled from the leaves of Angophora lanceolata, pinene 

 "was also found, and proved by the formation of its nitrosochloride. 

 This connection between the Angophoras and the Eucalypts is not 

 the only chemical evidence that we can produce. A few years 

 ago the Bureau of Agriculture for Western Australia sent to the 

 Technological Museum a sample of the kino from the "Red Gum" 

 Eucalyptus calophylla, and in the investigation of this kino a new 

 substance was discovered, this was named "Aromadendrin." Its 

 chemistry was undertaken by one of us and the results published 

 in the Proceedings of this Society, August 5th, 1896. 



In the year 1900 a new species of Angophora from the western 

 portion of this State was described by one of us in the Proc. Linn. 

 Soc, N.S.W. From the kino of this species (A. melanoxylon) a 

 substance was obtained chemically identical with aromadendrin 

 obtained from the kino of E. calophylla. A chemical connection 

 was thus shown to exist between these two genera, at near this 

 point, because eudesmin and not aromadendrin is generally the 

 principal constituent of this character occurring in Eucalyptus 

 kinos. When the additional chemical evidence respecting their 

 oils had been obtained we referred to the venation of E. calophylla, 

 and found it to correspond with that characteristic of the 

 Angophoras. 



We are not aware that the oil has yet been distilled from the 

 leaves of E. calophylla, but from the chemical evidence and the 



