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ISLAND LIFE. 



[part II. 



and the explanation of this fact given by Mr. Darwin— that 

 they are prevented doing so by the competition of better 

 adapted forms — is held to be sufficient. In this particular case, 

 however, we have some very remarkable evidence of the fact 

 of their non-adaptation. The intercourse between New Zealand 

 and Europe has been the means of introducing a host of common 

 European plants, — more than 150 in number, as enumerated at 

 the end of the second volume of the Handbook ; yet, although 

 the intercourse with Australia has probably been greater, only 

 two or three Australian plants have similarly established them- 

 selves. More remarkable still, Sir Joseph Hooker states: "I 

 am informed that the late Mr. Bidwell habitually scattered 

 Australian seeds during his extensive travels in New Zealand." 

 We may be pretty sure that seeds of such excessively common and 

 characteristic groups as Acacia and Eucalyptus would be among 

 those so scattered, yet we have no record of any plants of these 

 or other peculiar Australian genera ever having been found wild, 

 still less of their having spread and taken possession of the soil 

 in the way that many European plants have done. We are, 

 then, entitled to conclude that the plants above referred to have 

 not established themselves in New Zealand (although their seeds 

 may have reached it) because they could not successfully com- 

 pete with the indigenous flora which was already well established 

 and better adapted to the conditions of climate and of the 

 organic environment. This explanation is so perfectly in 

 accordance with a large body of well-known facts, including 

 that which is known to every one — how few of our oldest and 

 hardiest garden plants ever run wild — that the objection above 

 stated will, I feel convinced, have no real weight with any 

 naturalists who have paid attention to this class of questions. 



