476 
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. 
