126 TREE ANCESTORS 



way of the since sunken lands indicated by the topography of the 

 ocean bottom and by the coral islands and tectonic (structural) 

 lines across Polynesia. 



It seems probable, however, that Australia and New Zealand 

 were never actually connected in later geological times, that is to 

 say, since the higher plants were evolved. Otherwise New Zealand 

 should contain some traces of the animals, such as the marsupials, 

 and plants such as the Eucalyptus or gums that particularly char- 

 acterize the life of Australia. New Zealand has, however, been 

 shown to have been much more extensive in former than at the 

 present time, and it seems probable that it received its beeches 

 from the Antarctic continent during one of these times of extension 

 rather than by a land bridge between New Zealand and Australia. 



If Fagus or even Nothofagus were of southern origin, and I 

 think that it will be conceded by botanists familiar with the two 

 genera that they are the immediate descendants of a common 

 stock, it would be contrary to the general rule of past distribution 

 of the ancestors of our existing flora which in every case that has 

 been investigated show former cosmopolitanism in the great land 

 mass of the northern hemisphere and a simultaneous or subsequent 

 migration into southern lands. This statement is notably true 

 of the coniferous genera Araucaria and Dammara. It is likewise 

 true of the great antipodean families Proteaceae and Myrtaceae, 

 and many other and no less striking instances could be enumerated. 



It would seem that Nothofagus was more primitive than Fagus, 

 or at least that it is more like the original stock from which both 

 took their origin. This stock was probably evergreen in habit, 

 small in size and with relatively reduced leaves. If this supposi- 

 tion is justified it might be considered as furnishing another argu- 

 ment for the northern origin and southward migration of the 

 original stock, for the natural place to look for existing forms most 

 Hke their remote ancestors has been considered by some students 

 of distribution as being farthest away from the original center 

 of radiation — nearer this center they would tend to have been 

 replaced by successively later and later evolved forms. 



