42 R. H. CAMBAGE. 



leaves arranged along the branchlets in sessile, opposite 

 pairs at once attracts attention, and it seems remarkable, 

 considering that this appears to have been the form from 

 which the genus has evolved its present foliage, that 

 when this feature is wholly retained as in the cases of 

 E. pulverulenta and cordata, though in a moist climate, the 

 trees are depauperate and apparently languishing, as if the 

 failure to change their habit in response to some altered 

 environment will result in their extermination ; while on 

 the other hand, all the great giants of the genus are amongst 

 those which have developed petiolate, alternate leaves 

 after reaching at most a few feet high. The subject how- 

 ever, is an intricate one, and there are many phases of the 

 question to be investigated and considered before final 

 judgment can be pronounced. 



In considering the distribution of those Eucalypts which 

 show the most marked differences between the juvenile 

 and adult foliage, it is found that the extreme forms of 

 divergence are commonest in the Mountain Region, next 

 in the Ooastal Area, third on the Western Slopes, and least 

 in the Interior. The elements of temperature and moisture 

 therefore again appear to be important factors in regulating 

 this distribution, and when we consider the association 

 between the region of greatest diversity in leaf-form, and 

 the cold climate, we cannot but realise the important 

 influence which the uplift in the Kosciusko period has 

 exercised on the distribution of the Eucalypts in South 

 Eastern Australia. 



Amongst those species which show extreme diversity of 

 form and arrangement between the juvenile and adult 

 foliage in the Mountain Region are the following: — 

 Eucalyptus rubida, viminalis, amygdalina, dives, radiata 

 (in the lower altitudes), Smithii, globulus, Maideni, gonio- 

 calyx, nova-anglica, Macarthuri, Bridgesiana, Cambagei, 

 Gunnii, Risdoni, and in some instances cinerea. 



