The Genetic Phytogeography of the Southwestern 

 Pacific Area, with Particular Reference 



to Austraha 



By Ludwig Diels 



FROM THE TIME o£ J. D. Hookcr's famous Introductory 

 Essay, On the Flora of Australia, its Origin, Affinities, 

 and Distribution (1859), it has been known that a large, 

 Autochthonian element was a prominent feature of the Austral- 

 ian flora, and that there were strong Indo-Malayan affinities and 

 some relations to the antarctic regions. 



This evidence appeared to favor the assumption that Australia 

 had been isolated for a long time, that it had had early connec- 

 tions with the Malayan Archipelago, and that more recendy it 

 had been influenced by the south. Some years ago, however, this 

 doctrine was challenged by Wegener in his well-known theory 

 of the displacement of the continents. 



According to his idea, there was, in Palaeozoic times, a univer- 

 sal continent Pangaea. In the middle Jurassic, Antarctica-Aus- 

 tralia began to separate from this continent and to drift south- 

 eastward. It was still connected with South America in the early 

 Tertiary. Not until the older Quaternary did Australia separate 

 from Antarctica and move northward, and, even at that time, a 

 deep sea existed between Australia and the Malaysian Archi- 

 pelago. 



Now, if Australia had been joined to the southern regions for 

 the long time from the beginning of the Tertiary period to the 

 first part of the Quaternary, namely, during the epoch of the 

 evolution of Angiosperms, the southern element would be domi- 

 nant in the Australian flora. Let us see whether this is the fact. 



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