Chapter III 



—43- 



On Areas 



small areas to few large and the second in the reverse order. To 

 explain this regularity it is necessary to concede the significance of age 

 as a factor in distribution. The older species with extensive areas of 

 distribution reached New Zealand prior to its separation from AustraHa 

 and had enough time to become widely distributed there. Hence, it is 

 clear why in the zone of areas of least extent we find the smallest 



Fig. s. — Areas of species of different ages: 

 gaceae) in New Zealand. (After Willis). 



the genus Gunnera [Halorrha- 



number of widely distributed species. On the other hand, endemic 

 species — regarded by Willis as young species that had their origin 

 at a later time, after New Zealand had become an island — become more 

 and more rare, the greater the distance from the place of their origin. 

 Consequently, it was to be expected, and investigations confirmed this, 

 that the islands surrounding New Zealand would have a flora consist- 



