DISCUSSION. 425 



Mr. R. H. Cambage — Tlie physical features of New South 

 "Wales in'ovide excellent conditions for testing Jordan's Law in 

 regard to plants, inasmuch as the high mountain-range so 

 divides the climatic conditions that, on the eastern side, the 

 climate is moist and warm, while on the west the atmosphere 

 is dr3^ Taking some of the Box-trees belonging to the genus 

 Eucalyptus, results are found somewhat in support of Jordan's 

 Law, but for the most part the exam[)les rather fail to harmonise 

 with it; and it is thought that, although the law may hold for 

 some species which originated prior to the formation of a par- 

 ticular barrier, there are other causes which produce the same 

 results. On the eastern face of the mountain-barrier, JS. 

 hemiphloia is common, while on the western slope £J. albens is 

 plentiful. These are closely allied species, and there is some 

 uncertainty whether one is not a variety of the other. Where 

 the mountain is low in the Liverpool Range, E. albens comes 

 through with the drier atmosphere, and both species are then 

 found in the eastern area, being at times difficult to separate 

 botanically. Just beyond the western margin of the habitat of 

 E. albens occurs E. Woolhiana, a species closely allied in some 

 forms to E. hemiphloia, but distinct from E. albens, with which 

 it is often found growing. E. hemijjhloia and E. albens, which 

 are closely allied, are for the most part separated by a barrier. 

 E. hemiphloia and E. Woollsiana are separated by the same 

 barrier, and a greater distance, and are closely allied; while E. 

 albens and E. Woollsiana, found side by side, differ more from one 

 another than either does from E. hemiphloia. E. viminalis and 

 E. rubida, which are closely allied species, do not support the 

 Law, both occurring side by side, throughout the mountains, 

 though sometimes showing slight partiality for different geo- 

 logical formations. E. dives and E. amygdalina, allied species, 

 are also found together on the mountains, though the former 

 slightly prefers the dry, and the latter the moist side of the 

 highlands. E. stellulata and E. Moorei are closely allied, and 

 both found on the mountains. E. terelicornis, E. dealbata and 

 E. Bancrofti, all so closely allied that the latter two are some 



