218 
ISLAND LIFE. 
[part II. 
unknown means of conveyance ; but however this may be, the 
general character of the land-molluscs is such as to confirm 
the conclusions we have arrived at from a study of the birds 
and insects, — that these islands have never been connected 
with a continent, and have been peopled with living things by 
such forms only as in some way or other have been able to reach 
them across many hundred miles of ocean. 
The Flora of the Azores . — The flowering-plants of the Azores 
have been studied by one of our first botanists, Mr. H. C. 
Watson, who has himself visited the islands and made extensive 
collections; and he has given a complete catalogue of the 
species in Mr. Godman’s volume. As our object in the present 
work is to trace the past history of the more important islands 
by means of the forms of life that inhabit them, and as for 
this purpose plants are sometimes of more value than any class of 
animals, it will be well to take advantage of the valuable materials 
here available, in order to ascertain how far the evidence derived 
from the two organic kingdoms agrees in character; and also 
to obtain some general results which may be of service in our 
discussion of more difficult and more complex problems. 
There are in the Azores 480 known species of flowering-plants 
and ferns, of which no less than 440 are found also in Europe, 
Madeira, or the Canary Islands ; while forty are peculiar to the 
Azores, but are more or less closely allied to European species. 
As botanists are no less prone than zoologists to invoke former 
land -connections and continental extensions to account for the 
wide dispersal of objects of their study, it will be well to 
examine somewhat closely what these facts really imply. 
The Dispersal of Seeds . — The seeds of plants are liable to be 
dispersed by a greater variety of agents than any other organisms, 
while their tenacity of life, under varying conditions of heat and 
cold, drought and moisture, is also exceptionally great. They 
have also an advantage, in that the great majority of flowering 
plants have the sexes united in the same individual, so that a 
single seed in a state fit to germinate may easily stock a whole 
island. The dispersal of seeds has been studied by Sir Joseph 
Hooker, Mr. Darwin, and many other writers, who have made 
it sufficiently clear that they are in many cases liable to be 
