No. 544] BOTANICAL SOCIETY OF AMERICA 



248 



of its characteristic elements, such as the genus Euca- 

 lyptus, represents what the general vegetation of the en- 

 tire earth was like at the close of Mesozoic time, when 

 the continent of Australia was isolated from the rest of 

 the world. Elsewhere than in Australia climatic and 

 physiographic changes subsequently eliminated the Me- 

 sozoic types of vegetation and evolved new ones; but in 

 Australia the conditions remained almost stationary, and 

 that continent to-day, so far as its native flora and fauna 

 are concerned, is still in a late Mesozoic or early Neozoic 

 stage of development. It is an endemic flora not because 

 it has evolved new types by reason of its isolation, but 

 because it has remained stationary by virtue of this rea- 

 son, while the great bulk of the world's vegetation has 

 changed. 



And so the paleobotanist extends the right hand of fel- 

 lowship to the botanist and says, ' ' when you are puzzled, 

 or in doubt, don't despair, come to us," for individually 

 or collectively we can, probably, suggest reasonable ex- 

 planations, not only as to why living plants have come to 

 be where they are, but also how they have come to be 

 what they are. 



