38 R. H. CAMBAGE. 



of this species from just above the 2,000 feet level around 

 Goulburn upwards to the 6,000 feet level towards Kosciusko, 

 it is found that with the ascent the leaves get gradually 

 smaller and thicker, and the trees become dwarfed from 

 the rigid conditions and weight of winter snow, until at 

 last they appear as gnarled shrubs with interlacing branches 

 and the now thickened leaves have been reduced in length 

 from about 6 to 3 inches. 



It therefore appears that the sub-arid conditions of the 

 inland country, and the coldest effects of the mountains' 

 though extreme in their climatic influence, have so oper- 

 ated in regard to this particular phase of leaf character as 

 to bring about the same result. It is suggested however 

 that the modifications of the internal structure of the 

 leaves of two Eucalypts which originated before the 

 Kosciusko uplift, and developed until the present time 

 under those two extremes of climatic influence, would not 

 be the same, and although the leaves of E. coriacea at 

 6,000 feet, have their counterpart in the Interior at 500 

 feet, so far as the thickening character is concerned, yet 

 in their venation they are distinct from those of all specie^ 

 found in that dry region. 



Horizontal and vertical leaves. — The mature foliage o^ 

 almost all Eucalypts is arranged vertically, and this fact 

 furnishes strong evidence that there must have been con- 

 siderable development in the genus, for in the great majority 

 of cases the juvenile foliage is arranged horizontally. The 

 same remark in regard to the juvenile foliage applies 

 equally to its nearest allied genus, Angophora. There 

 seems little reason to doubt that the mature foliage also 

 was originally sessile and arranged horizontally, and that 

 the pendant, vertical form is the most recent adaptation. 

 Throughout the genus Eucalyptus thei e are various species 

 which show a connecting link amongst their mature foliage, 



