20 
BULLETIN 1087, U. S. DEPARTMENT OF AGRICULTURE. 
area occupied by the roots of a single 3-year-old plant was estimated 
to be 3 feet in diameter and 10 feet deep. 
Taproots of Grimm alfalfa taper more rapidly than those of less- 
hardy strains, but just below the crown there appears to be only a 
slight difference in the diameters of the taproots of the different 
varieties, as is shown in Table 5. In the number of branch roots 
the Grimm alfalfa exceeds the southern strains, as is indicated in 
Table 6. Grimm and Turkestan alfalfa show somewhat greater 
angles of divergence of the branch roots than southern-grown com- 
mon, but the variations are hardly sufficient to constitute distinguish- 
ing characteristics. As is shown in Table 7 the Grimm alfalfa dif- 
Fig. 14. — Root systems of Grimm alfalfa plants, the growth of one season. 
fers from the less hardy varieties by having more numerous fibrous 
roots, which are most abundant within 5J inches of the crown. In 
the southern-grown strains the fibrous roots are relatively sparse 
and quite uniformly distributed over the root system. Rooting 
rhizomes are often well developed; but, in this respect, the Grimm 
alfalfa is not quite so marked as the yellow-flowered kind. (Figs. 
14 and 15.) 
The root systems of Grimm alfalfa and the strain of Turkestan 
alfalfa studied are so similar that even the closest examination will 
not serve to distinguish between them. The chief difference is the 
greater uniformity of the root systems in the Turkestan variety. 
It appears possible, however, to distinguish the southern-grown 
common alfalfa from either of these varieties by close study of the 
root systems of a large number of plants. This can not be done 
where only one or two are available for study. 
