MIGRATIONS OF PLANTS 
tlement by plants gives us many hints about 
prehistoric climatic and geographical changes. 
Geologists generally believe that the British 
Isles were once joined to the mainland of Eur- 
ope. It was at this time that they were settled 
by vegetation. Some of this plant life came 
from Spain and some from southwest France; 
there was also a Germanic group. ‘The floating 
ice of the glacial period brought over hardy 
visitors from the Scandinavian peninsula. A 
few plant immigrants arrived from North 
America and landed on the west coast of Ire- 
land. 
St. Helena is an isolated volcanic mass built 
up seventeen thousand feet from the bed of the 
ocean. It therefore has its own peculiar vege- 
tation, a portion of which is believed to have 
been evolved on the spot from the one-celled 
state. According to Sir Joseph Hooker, forty 
out of fifty flowering plants and ten out of 
twenty-six Ferns “with scarcely an exception 
cannot be regarded as very close specific allies 
of any other plants at all.”” Sixteen of the Ferns 
are common to Africa, India or America and 
were probably carried there by the wind. 
[43] 
