472 
ISLAND LIFE. 
[part II. 
— notably in the case of the Azores and Bermuda. The cha- 
racter of the plants is also just what we should expect; for 
about two-thirds of them belong to genera of world-wide range 
in the temperate zones, such as Ranunculus , Prosera, Epilobium, 
Gnaphalium, Senecio , Convolvulus, Atriplex, Luzula, and many 
sedges and grasses, whose exceptionally wide distribution shows 
that they possess exceptional powers of dispersal and vigour of 
constitution, enabling them not only to reach distant countries, but 
also to establish themselves there. Another set of plants belong 
to especially Antarctic or south, temperate groups, such as Colo - 
banthus, Accena, Gaultkeria, Pernettya, and Muhlenbeclcia, and 
these may in some cases have reached both Australia and New 
Zealand from some now submerged Antarctic island. Again, 
about one-fourth of the whole are alpine plants, and these 
possess two advantages as colonisers. Their lofty stations 
place them in the best position to have their seeds carried away 
by winds; and they would in this case reach a country which, 
having derived the earlier portion of its flora from the side of 
the tropics, would be likely to have its higher mountains and 
favourable alpine stations to a great extent unoccupied, or 
occupied by plants unable to compete with specially adapted 
alpine groups. 
F ally one-third of the exclusively Australo-New Zealand species 
belong to the two great orders of the sedges and the grasses ; 
and there can be no doubt that these have great facilities for dis- 
persion in a variety of ways. Their seeds, often enveloped in 
chaffy glumes, would be carried long distances by storms of 
wind, and even if finally dropped into the sea would have so 
much less distance to reach the land by means of surface cur- 
rents ; and Mr. Darwin’s experiments show that even cultivated 
oats germinated after 100 days’ immersion in sea-water. Others 
have hispid awns by which they would become attached to the 
feathers of birds, and there is no doubt this is an effective mode 
of dispersal. But a still more important point is, probably, that 
these plants are generally, if not always, wind-fertilised, and 
are thus independent of any peculiar insects, which might be 
wanting in the new country. 
Why easily -dispersed plants have often restricted ranges 
