ALFALFA ROOT STUDIES. 
NONHARDY ALFALFAS. 
13 
As the term indicates, the group of nonhardy alfalfas includes 
those varieties and strains that can be grown successfully only in 
regions having such a mild climate that little or no winterkilling 
occurs. The Peruvian alfalfa is the only well-known variety of this 
group in the United States, and the area to which it is adapted is 
limited to sections where the minimum temperature seldom falls 
below 10° F. 
Fig. 8. — Root systems of plants of Grimm alfalfa, indicating considerable injury but 
only a small percentage of mortality in this variety during the 6-year period from 
1915 to 1920, inclusive. The root marked X represents a dead plant. 
PEETJVIAX ALFALFA. 
As few plants of the Peruvian variety survive the winter at Red- 
field, it was necessary to make observations on roots of plants of one 
season's growth. This is a purple-flowered alfalfa having a nar- 
row, upright crown, few crown branches, and only occasional root- 
ing rhizomes. The taproots are very prominent, and branch roots 
are few, small, irregularly distributed, and seldom rebranched. 
Fibrous roots, which are orenerallv more abundant near the surface 
in the hardier alfalfas, are sparse and uniformly distributed over 
the entire root system. "With the exception of the Poona alfalfa, the 
Peruvian alfalfa made the smallest root growth in the first season 
of any of the alfalfas studied at Redfield. The differences between 
the root systems of this variety and other varieties and strains of 
one season's growth are well shown by comparing Figure 10 with 
Figures 11 to 14, inclusive. 
103923°— 22 3 
