180 R. T. BAKER AND H. G. SMITH. 
the resins obtained from these trees also vary in agreement. 
Although in general appearance these “Pine Tree Resins” 
all appear to be similar, yet they vary in chemical 
behaviour. 
The two main species occurring in New South Wales are 
C. glauca and C. calecarata, and it is these species which 
produce the greater portion of the sandarac sent from this 
State. The resin of the latter species is perhaps better for 
varnish making than that of the former, and more closely 
approaches common sandarac in chemical constitution. 
The resins of C. calcarata andC. Macleayana are practically 
soluble in alcohol, and contain no resin which is precipi- 
tated on dilution with alcohol. In the resins of C. glauca 
and of C. verrucosa, there is a considerable amount of 
resin insoluble in a large quantity of alcohol, and con- 
sequently the resins of these species are less soluble than 
ordinary sandarac. ‘This difference in solubility in alcohot 
is evidently due to the varying amount of the two main 
resins—pimaric and callitrolic acids—and these again are 
governed by the constitution of the oil constituents of the 
plant. The difference in the amount of an acid resin, the 
potassium salt of which is insoluble in potash, also varies 
in the resins of the several species. 
We have obtained the resins of most of the species of 
Callitris, and with some of them from numerous localities, 
We hope that the completed results obtained with these 
will allow some order to be evolved, and a classification 
made of the resinous products of the Callitris of Australia. 
Summary of Results.— 
1. The genus Callitris may now be regarded as endemic 
to Australia, the North African species, in recent years 
included under that name being classed as a distinct genus 
—Tetraclinis. Both are also distinct from the South 
African genus Widdringtonia. 
