ILLUSTRATIONS (19). THE CACTUS FORM. 311 



How "long- did the Tapir continue to be regarded as a charac- 

 teristic form of the New Continent! And yet the American 

 Tapir is, as it were, repeated in that of Malacca (Tapirus 

 indicus* Cuv.). 



Although the Cactus form belongs, properly speaking, to 

 the tropical regions, there are some species in the New Con- 

 tinent, that are indigenous to the temperate zone on the 

 Missouri and in Louisiana; as, for instance, Cactus missuri- 

 ensis and C. vivipara. Back, in his northern expedition, saw 

 with astonishment, the banks of the Rainy Lake in lat. 48 4Qf 

 (long. 92 53') entirely covered with C. Opuntia. South of 

 the equator the Cactus does not advance further than Rio 

 Itata (lat. 36) and Rio Biobio (lat. 37) In the part of the 

 chain of the Andes lying within the tropics, I have found 

 species of Cactus (C. sepium, C. chlorocarpus, C. lonplandii) 

 on elevated plains from 9000 to upwards of 10,600 feet above 

 the level of the sea ; but in Chili, in the temperate zone, a far 

 more strongly marked Alpine character is exhibited by 

 Opuntia OvaUei, whose upper and lower limits have been 

 accurately determined through barometric measurements by 

 the learned botanist, Claude Gay. The yellow-flowering 

 Opuntia Ovallei, which has a creeping stem, does not descend 

 below 6746 feet, advancing as high as the line of perpetual 

 snow; and even above it, wherever a few masses of rock 

 remain uncovered. These little plants have been gathered 

 at spots lying at an elevation of 13,663 feet above the level 

 of the sea.* Some species of Echinocactus are also true 

 alpine plants in Chili. A counterpart to the much admired 

 fine-haired Cactus senilis is presented by the thick-wooled 

 Cereus lanatus, called by the natives Piscol, which has a fine 

 red fruit. We found it near Guancabamba, in Peru, on our 

 journey to the Amazon river. The dimensions of the Cactacese 

 (a group on which the Prince of Salm-Dyck was the first 

 to throw considerable light) present the most striking con- 

 trasts. Echinocactus Wislizeni, which has a circumference 

 cof seven feet and a half, with a height of four feet and a 

 quarter, is only third in size, being surpassed by E. ingens, 

 (Zucc.) and E. platyceras, (Lem.)f The Echinocactus Stainesii 

 attains a diameter of from two feet to two and a-half; E. 



* Claudio Gay, Flora Cliilensis, 1848, p. 30. 



f Wislizenus, Tour to Northern Mexico, 1848, p. 97. 



