PROCEEDINGS OF SECTION D. 479 



A. cordifolia, Cav., though commou around Sydney, is not known 

 to me on the higher parts of the mountains. 



These examples have been selected to show that in the coastal area 

 there are certain plants which favor particular geological formations, 

 while the conditions of climate remain the same ; but as the mountains 

 are ascended, and the cold increases, the climatic influences become 

 more important than the geological in deciding the limitations of these 

 plants. 



THE MOUNTAIN AREA. 



The division described as the mountain area is practically that on 

 both sides of the Great Dividing Range above an elevation of approxi- 

 mately 1,500ft. in the south to about 2,500ft. in the north, and ranging 

 to upwards of 7,000ft. in the south and about 5,000ft. in the north. 



This division includes some plants which do not occur in any other 

 part of New South Wales, being restricted to the higher altitudes owing 

 to their preference for cool conditions. It is interesting to trace the 

 effects of climate over this area from south to north. 



Eucalyptus coriacea, A. Cunn., the snow gum of Kosciusko, may be 

 found in Tasmania in some cases practically at sea-level ; but in coming 

 northwards it gradually ascends till, in the latitude of Sydney, it is not 

 found below an altitude of 2,500ft., while in northern New South Wales 

 it rarely descends below 3,000ft. On the other hand, while it thrives 

 at elevations of 5,000ft. in New South Wales, it is absent from the 

 higher parts of Mount Wellington, in Tasmania, which reaches about 

 4,600ft., the climate, perhaps, owing to an unsuitable aspect, being too 

 severe in a latitude so far south. 



The above remarks apply in a measure to another white gum — 

 E. viminalis, Labill ; but this tree is not able to withstand such extreme 

 cold as E. coriacea, and is found at lower levels in New South Wales. 



E. amygdalina, Labill (peppermint, or messmate), occupies a position 

 between the other two, and recollections of the pleasing effect of its 

 scented foliage are always associated with visions of a cool, in\ngorating 

 climate. 



In the central part of the mountain division, near the upper portion 

 of the Hunter River, there is a distinct break in the continuity of 

 the cold country flora, which is due to the influence of cHmate. Refer- 

 ence has recently been made by T. Griffith Taylor, B.Sc. (8), to the 

 temperature in this locality. Owing to the amount of denudation 

 effected by the Hunter River and its tributaries, the country is here 

 lower than in any other part of the Dividing Range, and some species 

 do not continue into the valley, although the majority reappear on the 

 opposite side. This intrusion of a western influence on the eastern 

 watershed causes an unusual associating of plants, and increases the 

 difficulty of correctly delineating the division boundaries. 



The Upper Hunter provides one of the most interesting localities 

 in New South Wales for studying the effects of climate on the general 

 flora. It is, perhaps, assisted to some extent by the geological forma- 

 tion, much of which is the same on both sides of the main range, viz., 

 Permo-Carboniferous. In other parts of the State the Great Dividing 

 Range acts as a cold barrier in separating the eastern and western floras 



