80 
ISLAND LIFE. 
[part I. 
Antiquity of Plants as affecting their Distribution . — We have 
already referred to the importance of great antiquity in en- 
abling us to account for the wide dispersal of some genera and 
species of insects and land-shells, and recent discoveries in fossil 
botany show that this cause has also had great influence in the 
case of plants. Eich floras have been discovered in the Miocene, 
the Eocene, and the Upper Cretaceous formations, and these 
consist almost wholly of living genera, and many of them of 
species very closely allied to existing forms. We have there- 
fore every reason to believe that a large number of our 
plant-species have survived great geological, geographical, and 
climatal changes ; and this fact, combined with the varied and 
wonderful powers of dispersal many of them possess, renders 
it far less difficult to understand the examples of wide dis- 
tribution of the genera and species of plants than in the case of 
similar instances among animals. This subject will be further 
alluded to when discussing the origin of the New Zealand flora, 
in Chapter XXII. 
