bY 11. II. GAMBAGE. 567 



are whitish towards the ends of the young phyllodia ; while, 

 in October, it was flowering, but no pods had formed ; and 

 the plant has not been identified. 



J. Jonesii is growing near Byrnes' Gap, noi-th of Yerran- 

 derie, as a very small Wattle, about 18 inches high, with 

 linely pinnate leaves.* This is apparently a somewhat rare 

 species, the type of which came from near Marulan. 



Eucalyptus meJliodora, the 'Yellow Box of the west, may 

 be seen soon after the Wollondilly is crossed ; and its pre- 

 sence suggests that the locality is, to some extent, open to 

 western influence. This species, however, is very versatile, 

 and able to withstand considerable extremes of heat and 

 cold, although it is rarely found whex'e the full moist coastal 

 influence operates. 



Associated with the Yellow Box, is E . alb ens, the White 

 Box of the Western Slopes, and I do not know of its occur- 

 ence nearer Sydney. This may justly be regarded as the 

 western analogue of E. hemiphloia, the common Box of Par- 

 ramatta. It seems fair to assume that this is an instance of 

 two forms, which may have been originally one and the same 

 species prior to the latest considerable uplift of Eastern 

 Australia, in late Tertiary or Pleistocene time.f That eleva- 

 tion created a "natural barrier," the Great Dividing Range, 

 between the moist climate of the coast, and the dry climate 

 of the west. With its steep eastern side facing the ocean, 

 and its long slopes turned to the dry west, this Great Divide 

 furnished the conditions necessary to establish two aspects 

 totally opposite in character. A species which survived 'on 

 both sides, would gradually develop features in response to 

 its surroundings, which, in course of time, would be con- 

 sidered sufficiently distinctive to warrant each form in having 



* iSoine plants were seen in December, 1911, from 3 to 5 feet high, 

 t " Geographical Unity of Eastern Australia," by E. C. Andrews, B.A. 

 Jourii. and Proc. Roy. Soo. N. S. Wales, 1910, p. 420. Presidential Address 

 by C. Hedley, F.L.S., these Proceedings, 1911, p.l3. 



