368 
AMERICAN JOURNAL OF BOTANY 
[Vol. io, 
green in color with an abundance of red pigment. Analyses of the leaves 
from the branch that had been ringed the previous year and from the 
check branches are presented in table 2. 
The data show that at the time of adding the nitrate (July 30), nearly 
a year after ringing, the check leaves had about 43 percent more nitrogen 
per unit of area than had the leaves of the ringed stem, that by August 22 
they had 65 percent more, and by September 9, 73 percent more. On 
July 30 the check leaves had 1.79 times as much nitrogen per unit of dry 
weight as the ringed leaves, on August 22, 2.12 times, and on September 
9, 2.24 times. 
The ash analyses clearly indicate that the ring has hindered the move¬ 
ment of ash constituents also, the check leaves on July 30, August 22, and 
September 9 having respectively ash contents per unit of area of 1.64, 2.04, 
and 1.56 times that of the leaves from the ringed stem. 
From these experiments with peach and lilac, it is very evident that the 
ringing has hindered the upward movement through the stems of both 
nitrogen and ash constituents. One could not conclude from these experi¬ 
ments alone, however, that the nitrogen or ash constituents move chiefly 
through the phloem instead of the xylem, because it might be true that 
they move up very largely through the newly formed xylem cells. The 
ring has not only cut the phloem, but has also prevented the formation 
of new xylem at the point of ringing. Furthermore, the changed growth 
above the ring might in some other way influence the nitrogen movement. 
In order to eliminate some of these difficulties, another set of experi¬ 
ments was started after the shoots had become well developed and the 
leaves were mostly formed. Samples of leaves were taken at the time the 
rings were made and nitrate spread on the soil, and again later at different 
intervals. Because of an accident to the drying oven, most of the samples 
taken on the day of ringing were lost, and a second set was taken two days 
later but many of these also were later lost. These trees were growing 
in a poor, sandy soil, and at the beginning of the experiment the leaves 
were yellowish green and very characteristic of peach trees grown in soils 
deficient in nitrogen. A few weeks after applying the nitrate, the leaves 
on all excepting- the ringed branches became darker green, and in many 
cases there seemed to be a renewal of shoot growth. The results of the 
analyses of this set are presented in table 3. For tree C, all the samples 
taken at the time of ringing were lost except two, one of which consisted 
of the younger leaves from near the tips of several branches and the other 
of older, basal leaves. When samples were taken from this tree on October 
7, the upper leaves were kept separate from the basal leaves. The young 
upper leaves from the ringed stem were very deficient in chlorophyll and 
were much curled. 
It is evident from these results that, even after the new xylem and 
leaves have been developed, the cutting of the phloem has hindered the 
