1899] ORIGIN OF AUSTRALIAN FLORA 283 



lands and of species congeneric with these. A few of these species 

 occur also in Western Australia ; in the eastern districts they are 

 more abundant in the cooler mundane country, and it is especially 

 in the latter that are found forms conspecific with, or closely allied 

 to, forms now forming part of the Antarctic flora, accepting this term 

 in the conventional sense, that is, as embracing genera now largely 

 or entirely restricted to southern cold temperate lands. It is admitted 

 that these facts do, at first sight, favour the view of migration on a 

 large scale followed by partial overpowering of the indigenous flora. 

 But when we consider what is known of the history of Australia since 

 late Cretaceous times the matter wears a different aspect. We have 

 every reason to believe that since these times considerable portions of 

 Eastern Australia have enjoyed a climate almost identical with that 

 of Indo-Malaya, a climate, too, still prevailing in the north and north- 

 east. We know, moreover, that in early tertiary times the floras of 

 both countries were in a large measure identical. Is there anything 

 remarkable, therefore, in the evidences of fioristic affinity between the 

 two regions ? It will perhaps be conceded, as Professor Tate himself 

 has conceded, that a certain proportion of the Australian species of 

 genera common to these two neighbouring areas are descendants from 

 the primitive flora, but that by far the larger number are immigrants. 

 This, however, assumes our possession of complete records respecting 

 the two floras from Eocene times to the present ; and that we have 

 anything like such records is an assertion no competent person would 

 take upon himself to maintain. 



But migration there has been, and the number of identical species 

 and such a fact as the discovery of outlying forms allied to Indo-Malayan 

 on the Bellenden-Ker range in North Queensland prove it, as also does 

 the existence of " Australian " forms on the mountains of New Guinea, 

 and in less number in various parts of Indo-Malaya and Eastern Asia, 

 if, indeed, these last be not descendants from the primitive flora. 

 Moreover, the trend of migration from the north has undoubtedly 

 predominated over that from the south. But are we justified in 

 assuming from this that any superiority is inherent in the Indo- 

 Malayan flora over the Australian ? What are the data ? A number 

 of hygrophilous genera and a certain proportion of hygrophilous species 

 are common to the two regions. Now the Indo-Malayan flora, 

 exception made for that of Timor, in some measure xerophilous, is and 

 has long been a hygrophilous flora; while in Australia since Eocene 

 times, if the view above enunciated be correct, hygrophilous types 

 have had to struggle with xerophilous ones, which latter to-day still 

 form a large element in its flora. Whatever in this case the means 

 whereby migration has been brought about, its trend must, other things 

 being equal, have borne direct relation to the size — or what comes 

 approximately to the same thing, the comparative fioristic richness — 

 of the areas between which the interchange has been made. We have 



