ALFALFA 323 



385. Seedlings. Alfalfa seedlings are poorly adapted 

 to cope with ordinary weeds because the initial growth is 

 largely centered in root production. No exact study seems 

 to have been made of the relative rate of growth in seed- 

 lings of roots and shoots. Porter at the Minnesota Experi- 

 ment Station records that plants two months old had roots 

 3 feet long and tops 10 inches high ; at five months the 

 roots were 6J feet long and the tops 16 inches high. 



386. Rootstocks. Common alfalfa rarely shows any 

 trace of rootstocks. These are, however, well developed 

 in some forms of sickle alfalfa, and remarkably so in 

 Medicago saliva Gaetula from Tunis, in which they may 

 reach a length of 3| feet. They also appear commonly 

 in the variegated hybrid alfalfas, and less so in Turkestan 

 and Mongolian alfalfas, but appear to be absent in the 

 Peruvian and Arabian forms. 



Oliver has bred some hybrids remarkable for the extent 

 to which they develop rootstocks, at least under green- 

 house conditions. Some of the hybrids form a dense 

 matted growth, a single plant covering a surface of several 

 square feet, and presenting much the general appearance 

 of white clover. The value of these for pasturage purposes 

 is suggested. 



Oakley has recently described some- extraordinary 

 examples of sickle alfalfa. These produce horizontal 

 roots two to four feet long, which at intervals give rise 

 to erect leafy shoots. These shoots may grow from as 

 great a depth as twelve inches, and commonly arise from 

 nodular swellings on the roots. 



The development of rootstocks is greater when plants 

 are grown isolated than when sown thickly. It seems 

 also to be encouraged by partly covering the plants with 

 soil. True rootstocks on alfalfa were first noted on 



