ELASTIC SUBSTANCE ON SHOOTS AND YOUNG LEAVES. 133 
On THE ELASTIC SUBSTANCE OCCURRING on THE 
SHOOTS anp YOUNG LEAVES or HUCALYPTUS 
CORYMBOSA AND SOME SPECIES or 
ANGOPHORA. 
By Henry G. SMITH, F.c.Ss., Assistant Curator, 
Technological Museum, Sydney. 
[Read before the Royal Society of N. 8S. Wales, July 1, 1908. } 
WHEN the buds and very young leaves of H. corymbosa 
are in active growth they are covered with an elastic 
Substance, which, under favourable conditions, can be 
stretched to a considerable extent. The main structure 
of the leaf, beneath the substance, can be readily broken 
without detaching the coating. It has been thought that 
this elastic substance was peculiar to this Hucalypt, but 
I have found it occurring on the shoots and young leaves 
of both Angophora lanceolata and A. intermedia. This 
fact is particularly interesting as it adds another proof of 
the close relationship existing between the Angophoras 
and those Kucalypts which have a corresponding leaf 
venation. H. corymbosa is perhaps the best representative 
of this group of Kucalypts. 
In a recent work by R. T. Baker and myself,* we were 
able to show a remarkable affinity between the ‘° Blood- 
woods ”’ (to which E. corymbosa belongs) and A. lanceolata, 
judged by the chemical constituents of their oils as well as 
by their leaf venations. The evidence now submitted 
strongly supports our previous observations in regard to 
these two genera. I am not aware that any previous 
research into the properties or composition of this elastic 
substance has been undertaken. I was thus anxious to 
* A Research on the Eucalypts. Government Printer, Sydney, 1902. 
