PLATE X. 
These roots had a length of 9 feet 4% inches and were nine months old. The field had 
been sown to alfalfa with oats in the spring and one cutting of alfalfa hay was made in the 
fall. The yield was about three-fourths of a ton. 
The difference in the development of these young roots is no greater than is often found, 
and I see no satisfactory explanation for the facts. The yield from fields in which the roots 
are small is just as good as from those in which the roots are larger, without any perceptible 
difference in the quality of the hay. Some of these seedling roots were almost as large as any 
of the roots of the plants four years old, growing in an adjacent land. I do not know how soon 
an alfalfa root may acquire its full growth. 
PLATE XL 
It was not possible to get the details of the small roots in photographs of plants whose roots 
were from 7 to 1114 feet long. We present in this plate the terminal portions of two roots, 714 
feet from the surface, each showing nodules, which appear as round or irregular black spots on 
the roots. 
The extremities of the tap roots, I regret, were broken off. 
PLATE XII. 
This plate represents the terminal portion of a tap root, 11 feet 9 inches long. There was 
a fair degree of moisture, but no water at this point. There are a few nodules observable in 
the plate, but they are few in number and small. This root was in a perfectly healthy condition 
and was apparently growing vigorously. The spongioles were long, bright, and had every 
appearance of health and vigor. 
PLATE XIII. 
This is a mat of roots as it was exposed near the bottom of an excavation by the removal 
of a part of a layer of coarse gravel, leaving the roots in a cavity. It was due to the looseness 
and size of the gravel that we were able to obtain the fibrous roots intact. This gravel bed was 
filled to its upper margin with water, into which these roots penetrated for about 6 inches. 
PLATE XIV. 
Root nodules are often small and present in large numbers, being strung along the root as 
small, moie oi less lound or cylindrical bodies, as may be seen to great advantage by digging 
up a plant of some of the small growing vetches or red clover, although on the latter the 
nodules are less abundant and larger. They usually occur on the roots of the alfalfa, isolated 
or grouped together, often forming colonies of considerable size,, as shown in the accompanying 
p ate, the largest of which were over 2H inches across. These groups were of all shapes; some 
were globular, others flat and irregular in outline. The figures show this plainly. Some of 
t 10 m were broken and shrivelled; others were white and solid. The nodules represented were 
found at the depths of from 2% to 5 feet. 
PLATES XV., XVI., AND XVII. 
The following series of three plates, with six plants, is intended to show the progress of 
the decaying of the roots at the crown, mentioned elsewhere in this bulletin. 
In the first plate one part of the plant has been pulled to the side to show the cavity, 
which would otherwise have scarcely been seen. In the second one the root has been split down 
to show a more advanced stage of decay, and also the manner and depth to which it penetrates 
into the interior of the roots. The rest show different stages in its advance and the manner in 
which it affects the crown, finally killing it. 
PLATE XVin. 
It is stated in the text, under the head of Roots, that it is difficult to explain the fact that 
alfalfa plants whose roots have been cut by gophers or mice continue to grow. As we believe 
the long loots to be necessary to the feeding of the plant, the statement is made in this connec¬ 
tion that the alfalfa root does not, when eaten off, throw out adventitious roots, which are 
sufficient to supply so heavy a feeder as this plant is. The following plate is intended to show 
this and is of plants said to be ten years old. The plants were very much crowded and were all 
small. They were plowed up on April 29th, and the one with the smallest roots had as large 
a growth of top as any of the other plants. I cannot judge how long it was since the injury 
to the roots occurred 
