68 TILLERS OF THE GROUND CHAP. 



could be got from South America, from Arabia, 

 from Turkestan, and so on. Among these, one 

 from Peru distinguished itself by its rapid growth 

 and the way it went on growing after it was cut, 

 and also the way it grew even in winter. It was 

 thought then that it would be a good plant to 

 grow, but unfortunately it proved to be very 

 sensitive to frost. In a great number of the stations 

 where it was tried it was promptly killed down by 

 the frost, while some other varieties were not 

 affected. A note was therefore made to the effect 

 that this variety is sensitive to cold, and is only 

 suitable for places like Arizona, where there is not 

 severe winter frost. But and this is the curious 

 point while it is very sensitive to severe cold, it is 

 not affected at all by moderate cold, and goes on 

 growing quite contentedly through the cold weather 

 of Arizona. The other varieties, which are not 

 killed by severe frost, yet stop growing so soon as 

 the weather becomes cold. 



Just consider what this means. One of the 

 hardy alfalfas will live through a severe winter, 

 even in the northern parts of the United States, 

 but it promptly stops growing as soon as it becomes 

 even a little cold. Peruvian alfalfa is killed by 

 severe frost, but it grows on steadily through 

 moderate cold, when the other kinds are simply 

 waiting for the warm weather to come again. 



