138 



PAMPAS. 



Sept. 1833. 



partly explain the circumstance? We thus have lines of 

 richly-manured land serving as channels of communication 

 across wide districts. 



Near the Guardia we find the southern limit of two 

 European plants^ now become excessively common. The 

 fennel in great profusion covers the ditch banks in the 

 neighbourhood of Buenos Ayres^ Monte Video^ and other 

 towns. But the cardoon {Cynara cardunculus)^ has a far 

 wider range : it occurs in these latitudes on both sides of the 

 Cordillera^ across the continent. I saw it in unfrequented 

 spots in Chile, Entre Rios, and Banda Oriental. In the 

 latter country alone, very many (probably several hundred) 

 square miles are covered by one mass of these prickly plants, 

 and are impenetrable by man or beast. Over the undulating 

 plains, where these great beds occur, nothing else can live. 

 Before their introduction, however, I apprehend the surface 

 supported as in other parts a rank herbage. I doubt 

 whether any case is on record, of an invasion on so grand a 

 scale of one plant over the aborigines. As I have already 

 said, I nowhere saw the cardoon south of the Salado ; but 

 it is probable that in proportion as that country becomes 

 inhabited, the cardoon will extend its limits. The case is 

 different with the giant thistle (with variegated leaves) of the 

 Pampas, for I met with it in the valley of the Sauce. Ac- 

 cording to the principles so well laid down by Mr. Lyell, 



* D'Orbigny (vol. i., p. 474), says that the cardoon and artichoke are 

 both found wild. Dr. Hooker (Botanical Magazine, vol. Iv., p. 2862), 

 has described a variety of the Cynara from this part of South America 

 under the name of inermis. He states that botanists are now generally 

 agreed that the cardoon and the artichoke are varieties of one plant. I 

 may add, that an intelligent farmer assured me, he had observed in 

 a deserted garden, some artichokes changing into the common cardoon. 

 Dr. Hooker believes that Head's vivid description of the thistle of the 

 Pampas applies to the cardoon ; but this is a mistake. Captain Head 

 referred to the plant, which 1 have mentioned a few lines lower down, 

 under the title of giant thistle. Whether it is a true thistle I do not 

 know ; but it is quite different from the cardoon, and more like a thistle 

 properly so called. 



