IMMIGRANT PLANTS. 165 



tracts of country, especially in the rather moister 

 southern provinces. I was informed that, with the 

 strange expectation that it would be useful as fodder, 

 an Englishman had imported a sack of the seed, 

 which he had spread broadcast somewhere in the 

 neighbourhood of Concepcion. ^ Many other European 

 plants have been introduced, either intentionally or 

 by accident, and have in some districts to a great 

 extent supplanted the indigenous vegetationl As to 

 many of these, it appears to me probable that their 

 diffusion is due more to the aid of animals than the 

 direct intervention of man. This is especially true 

 of the little immigrant which has gone farthest in 

 colonizing this part of the earth — the common stork's- 

 bill {Erodiitm ciaitariuni), which has made itself 

 equally at home in the upper zone of the Peruvian 

 Andes, in the low country of Central Chili, and in the 

 plains of Northern Patagonia. Its extension seems to 

 keep pace with the spread of domestic animals, and, 

 as far as I have been able to ascertain, it is nowhere 

 common except in districts now or formerly pastured 

 by horned cattle. It is singular that the same plant 

 should have failed to extend itself in North America, 

 being apparently confined to a few localities. It is 

 now common in the northern island of New Zealand, 

 but has not extended to South Africa, where two 

 other European species of the same genus are estab- 

 lished. 



In considering the facts relating to the rapid 

 extension of certain plants when introduced into new 

 regions, and the extent to which they have supplanted 

 the indigenous species, I confess that I have always 



