bY K. H. CAMBAGE. 633 



Little, therefore, can be said in favour of dispersal by birds beiujj; 

 responsible for the distribution in this case. 



The second suggestion, that it may have gradually spread from 

 parent-plants, assisted by birds, presents certain points which are 

 exceedingly difficult of proof, but nevertheless pi'ovide material 

 for some interesting lines of thought. Adopting Mueller's opinion 

 that this plant is only a variety of A. correi/olia, which species 

 occurs in the coastal area from about Sydney and the Nepean 

 northwards, it might perhaps be considered a mountain-form 

 which has climbed to its present height, and gradually developed 

 differences owing to environment. Its present north and south 

 extremes of range would then have to be regarded as having been 

 connected through the coastal species. There are such large 

 breaks in the continuity of this range of distribution, between 

 coastal and mountain localities, so far as at present known, that 

 this explanation cannot be considered as very satisfactory. 



A further possibility and theory of its having gradually spread 

 from parent-plants would involve its antiquity. Physiographers 

 have reason to believe that, in early Tertiary time, New South 

 Wales was an almost level tract of land, a peneplain, not raised 

 much above sea-level; and that the mountains which form the 

 present Main Divide, north and south, were not elevated until 

 late Tertiary.* If A. correi/olia had spread from the east coast, 

 inland for two or three hundred miles prior to tlais uplift, and 

 while the climatic conditions over that area were fairly uniform, 

 then the occurrence, to-day, of resultant forms or varieties of that 

 species in the elevated or western areas, with altered climatic 

 conditions, would seem by no means an impossibility. In regard 

 to the antiquity of the species, all that can be said at present, is 

 that representatives of the genus are spread over, at least, parts 

 of New South Wales, Victoria, and Western Australia, while 

 the closely allied genus, Eriostemon, has representatives in all the 



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

 Joiun. Proc. Roy. Soc. N. S. Wales, 1910, p. 420. Presidenlial Address 

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



