PLANTS WITH NUTRITIVE ROOTS. 333 



Rye and barley, which resist cold better than 

 wheat, are cultivated on the highest regions, but 

 only to a small extent. Oats do not answer well in 

 New-Spain, and are very seldom seen even in the 

 mother-country, where the horses are fed on barley. 



The potato appears to have been introduced into 

 Mexico nearly at the same period as the cereal 

 grasses of the Old Continent. It is certain that it 

 was not known there before the arrival of the 

 Spaniards, at which epoch it was in use in Chili, 

 Peru, Quito, and New-Grenada. It is supposed by 

 botanists that it grows spontaneously in the moun- 

 tainous regions; but our author asserts that this 

 opinion is erroneous, and that the plant in question 

 is nowhere to be found uncultivated in any part of 

 the cordilleras within the tropics. According to 

 Molina, it is a native of all the fields of Chili, where 

 another species, the Solanum cari, still unknown in 

 Europe, and even in Quito and Mexico, is grown ; 

 and M. Humboldt seems to consider that country as 

 the original source of it. It is stated that Sir Walter 

 Raleigh found it in Virginia in 1584 ; and a question 

 arises, whether it arrived there from the north, or 

 from Chili, or some other of the Spanish colonies. 

 Our traveller seems to consider it not improbable 

 that it had been conveyed from some of the Spanish 

 colonies by the English themselves. 



The plants cultivated in the highest and coldest 

 parts of the Andes and Mexican cordilleras are po- 

 tatoes, the Trop&olum esculentum, and the Clieno- 

 podium quinoa. The first of these are an important 

 object in the latter country, as they do not require 

 much humidity. The Mexicans and Peruvians pre- 

 serve them for a series of years, by destroying their 

 power of germinating by exposure to frost, and 

 afterward drying them, a practice which our au- 

 thor thinks might be followed with advantage in 

 Europe. He also recommends obtaining the seeds 

 of the potatoes cultivated at Quito and Santa Fe, 



