30 K. H. CAMBAGE. 



were apparently greater before the Main Divide shut off 

 the coastal influence in the Kosciusko period than at present. 

 Here we look for evidence of plants having devised means 

 of adapting themselves to drier conditions, but the change 

 in the vegetative form over this area should not be so great 

 as that of the Mountain Region, where all the factors have 

 operated to make the extremes greatest between early 

 Tertiary and present day conditions. 



Grouping of Eucalypts. 



In attempting to arrange the various Eucalyptus species 

 into groups which represent certain special features, the 

 difficulty is encountered of deciding upon the line of demar- 

 cation between characters which closely approach each 

 other. In the present discussion the subject of grouping 

 is only treated on general lines which are sufficient how- 

 ever to show that certain features are usually the result 

 of a particular climate, aspect, or geological formation, or 

 of a combination of these various factors, although in some 

 instances the exceptions to what appear to be general 

 rules are, in the light of our present knowledge, most 

 marked and perplexing. 



For the purpose of grouping, an investigation of some of 

 the following features is instructive : — 



Barks — smooth, scaly, scaly to subfibrous, fibrous, and 



hard-furrowed. 

 Timbers — texture and colour. 

 Leaves — size, thickness and venation. 

 Anthers — parallelantherae, porantherse, and renantherse. 

 Oil constituents — pinene, eucalyptol (cineol) and phel- 

 landrene. 



Barks. 

 For the purpose of discussing the distribution of vari- 

 ous kinds of bark, only well marked types have been 

 selected, between each of which there are insensible grada- 



