37 



The sesquiterpenes, or allied bodies, only occur as a rule in small amount in 

 the leaf oils of the Callitris, those of C. Macleayana, C. robusta and C. verrucosa 

 containing the greatest quantity. 



Phenols do not occur in the Callitris leaf oils to any great extent, as only 

 in two species was an indication for a phenol obtained, these were C. gracilis and 

 C. rJiomboidea , but the amount present was too small for determinative purposes. 

 Of course the phenol found in Callitris timber (callitrol) may extend to the wood 

 of the branchlets, and traces might thus be found with the leaf oils. 



The specific gravity of the oils was taken in comparison with that of water 

 at 15° C. in all cases. 



X. THE CONE. 



The distinctive characteristics of this organ of the Callitris have already been 

 given under Article II. The fruits occur generally below the male inflorescence, 

 which is a natural arrangement, as thus pollination is, in a certain measure, 

 assured. 



The cone may be said to be almost uniformly spherical in shape, and also to 

 consist of an equal number of valves, the one exception being C. Macleayana 

 which has 6-8 valves and is pyramidal in form. 



The general contour of the cone may thus be said to differ from that of 

 any living Conifer, certainly from Tefraclinis and Widdringtonia, of North and 

 South Africa respectively. 



They var}' in size from half an inch in the case of C. intratropica to over 

 an inch in C. robusta, whilst the pyramidal cone of C. Macleayana may be said 

 to average quite an inch in height. 



The nature or character of the external surface can be used in a measure 

 as a taxonomic aid, for dividing the species into classes; C. robusta, C. verrucosa, 

 C. tuberciilata, C. glaiica, C. intratropica, C. arenosa, C. propinqua, have all more 

 or less worted surfaces, whilst C. calcarata, C. Mitelleri, C. oblouga, C. Drmnmondi, 

 have them either smooth or even shining. 



In their mature condition they are hard and almost ligneous. 



