22 BULLETIN 1087, U. S. DEPARTMENT OF AGRICULTURE. 
Figure 15 shows roots of one of the most upright, narrow-crowned 
forms of yellow-flowered alfalfa that has been introduced. Seven of 
these plants have distinct taproots and five show a decided branching 
tendency. The branch roots 
are put forth obliquely and 
form a somewhat greater 
angle with the taproot than 
is the case with Grimm and 
Turkestan. The crown is 
quite similar to that of the 
Grimm except that the 
crown branches and rhi- 
zomes are smaller and more 
numerous. Fibrous roots 
are relatively abundant. 
Prostrate y ell oir-fl oi nered 
alfalfa . 8 — The prostrate 
yellow-flowered alfalfas are 
characterized by very broad 
deep-set crowns, well-devel- 
oped rhizomes, and dense 
root systems. Taproots are 
either not' apparent or are 
very short and indistinct. 
As shown in Table 6, branch 
roots are somewhat more 
numerous than in Medicago 
sativa. The angle that the 
branch roots form with the 
taproot is somewhat greater 
than with purple-flowered 
and hybrid alfalfas. A 
large percentage of the 
branch roots originate from 
the rhizomes, thus suggest- 
ing that the highly devel- 
oped root system is at the 
expense of the taproot and 
its branches. Rhizomes are 
longer and more branching 
than in the common or 
variegated alfalfas. Fibrous roots occur in considerable abundance 
in all parts of the root system. (Figs. 16 and IT.) 
8 The alfalfa considered is S. P. I. No. 20717 (lTeriicago falcata), from Kharkof Prov- 
ince, southwestern Russia, a wild form. 
Fig. 16. — Root system of a prostrate yellow-flowered 
alfalfa plant, the growth of six seasons. 
