Personality of plants

MIGRATIONS OF PLANTS
and thoroughly naturalized in a strange coun-
try that they go a long way toward supplanting
the original inhabitants in a very short time.
It was Darwin who first noticed the extensive
conquests of the Cardoon Artichoke (Cynara
Cardunculus) in South America. In one sec-
tion, these prickly plants covered an area of
several hundred square miles, having entirely
superceded the aborigines.
It is well known that the most troublesome
of the American weeds are of British origin.
On the other hand, the American water weed
Anacharis blocks up small English streams.
The grass called Stipa Tortilis has captured
the steppes of southern Russia. The love of
change seems to be an inherent tendency in
plantdom. The Pigweed and the Morning
Glory have come north from the tropics. The
Canada Thistle, originally a foreigner in North
America, has spread all over Canada and New
England. The American Erigeron Canadense
has emigrated to all parts of the world. The
flora of Scandinavia, like its people, are aggressive
colonizers. More than one hundred and
fifty species have reached New Zealand alone
[49]