ALFALFA ROOT STUDIES. 



17 



The angle which the branch roots form with the taproot is quite 

 similar in all the alfalfas studied, with the exception of the yellow- 

 flowered varietj^ where this angle is somewhat greater. Fibrous 

 roots, while more numerous than in Peruvian and Poona alfalfas, 

 are relatively sparse and well distributed over the root system, differ- 

 ing in this respect from the hardier varieties. (Table 7, column 4.) 

 Booting rhizomes are fewer and not so well developed as in northern- 

 grown common, Turkestan, or Grimm. (Fig. 12.) 



Fig. 12. — Eoot systems of southern-grown common alfalfa plants, the growth of one 



season. 



Table 7. — Estimates of the prominence of the 'branch roots and the relative aliun- 

 (lance of fibrous roots in different kinds of alfalfa at Redfleld, S. Dak. 



Relative 

 abun- 

 Kmd. „„„oi^_ >^ror,o>, dance of 



nbrous 

 roots. 



Southern-grown common 300 1 85 2 35 



Northern-grown common 75 92 92 



Turkestan 



Grimm 



Decumbent yeUow flowered 



Prostrate yellow flowered 



1 Few branch roots; pro min ent, taproots. 

 3 Branch roots numerous; taproot indistinct. 



Nnmber 



Promi- 



of plants 



nence of 



consid- 



branch 



ered. 



roots. 



300 



185 



75 



92 



75 



96 



225 



96 



19 



3 100 



22 



98 



2 Rather sparse. 

 * Very abundant 



XOBTHEKN-GKOWX COMMON ALFALFA. 



In the United States the hardy strains of common alfalfa are 

 largely the result of selective acclimatization, although in many cases 

 the presence of a small percentage of Medicago falcata blood has 

 contributed to the hardiness of these strains. 



