126 FENNEL AND CARDOON. [chap. vi. 



pour d6poser leurs excremens, dont on trouve des monceaux 

 dans ces endroits." Does this not 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 extraordinarily common. 

 The fennel in great profusion covers the ditch-banks in the 

 neighbourhood of Buenos Ayres, Monte Video, and other 

 towns. But the cardoon {Oynara carduncuhis)* has a far 

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

 the Cordillera, across the continent. I saw it in un- 

 frequented 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 now live. Before their introduction, how- 

 ever, the surface must have 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. According to the principles so well 

 laid down by Mr. Lyell, few countries have undergone more 

 remarkable changes, since the year 1535, when the first 

 colonist of La Plata landed with seventy-two horses. The 

 countless herds of horses, cattle, and sheep, not only have 

 altered the whole aspect of the vegetation, but they have 

 almost banished the guanaco, deer, and ostrich. Number- 

 less other changes must likewise have taken place ; the 

 wild pig in some parts probably replaces the peccari ; packs 



* M. A. d'Orbigrny (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 that 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 I 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. 



