16 



BULLETIN 1087, U. S. DEPARTMENT OF AGRICULTURE, 



Division of the taproot occurs less frequently than in the Grimm and 

 Turkestan varieties. 



Table 6 tends to show that branch roots in the southern-grown 

 common alfalfa are perceptibly less abundant than in the Turkestan 

 and Grimm. They are, however, relatively large, thus making the 

 branching system appear somewhat more prominent (Table 7, col- 

 umn 3) than the number recorded would indicate. 



Fig. 11. — Root systems of plants of Poona alfalfa (Medieayo satica), the growth of 



one season. 



Table 6. — Nu)ither of branch roots occurring in different kinds of alfalfa at 

 RedfieU, S. IMk., in 1917, 1919, and 1920. 



[Studies in 1917 and 1919 made on 1916 seedings; in 1920, on 1915 seedings.] 





Plants 

 observed. 



Counts of branch roots 2 mm. or more in diameter from crown 

 to IS inches below. 



ICind. 



Num- 

 ber, 

 each 

 date. 



Average 

 distance 



apart 

 (inches). 



May, 1917; 

 1 season's 

 growth. 



August, 1919; 

 4 seasons' 

 growth. 



October, 1919; 

 4 seasons' 

 growth. 



September, 1920; 

 6 seasons' 

 growth. 





Mor- 

 tality, 

 1916-17 



(per 

 cent). 



Aver- 

 age 



branch 



roots 

 per 



plant. 



Mor- 

 taUtv, 

 1916-19 



(per 

 cent). 



Aver- 

 age 

 branch 



roots 

 per 



plant. 



Mor- 

 tality, 

 1916-19 

 (per 

 cent). 



Aver- 

 age 

 branch 



roots 

 per 



plant. 



Mor- 

 tality, 

 1916-19 

 (per 

 cent). 



Aver- 

 age 



branch 



roots 

 per 



plant. 



Southern -grown 



100 



9.T 



1.37 

 1.32 

 1.45 



2.12 

 1.56 



None. 

 None. 

 None. 



2.15 

 3.88 

 4. .33 



13 



None. 



5 



3. .52 

 5.20 

 4.34 



32 

 9 

 4 



3.68 

 4.24 

 3.96 



















Southern-grown 

 common 



32 

 32 



40 



15.78 















5 

 None. 

 None. 



5.93 



Decumbent yellow 

 flowered 



19 













11.47 



Prostrate yellow 

 flowered 



22 2. 1 8 















6.90- 























1 Thelarge number of branch roots in southern-grown common alfalfa is probably due to extensive plani 

 mortality between 1915 and 1920, which probably left the plants with the greater branch-root development , 



