372 
AMERICAN JOURNAL OF BOTANY 
[Vol. io, 
separately, but there were so few leaves on a twig and these were so variable 
in size that thirty leaves were taken from each treatment and these were 
divided into three samples each for analysis. The day after the nitrate 
was added heavy rains washed it into the soil. The analyses are presented 
in table 4. 
The data indicate that the leaves from the check stem increased in 
nitrogen content per unit of area, while those from the ringed stem have 
slightly decreased. A similar gain by the check leaves and loss from the 
ringed is apparent in the ash analyses. 
Similar experiments were performed in 1920 with Acer platanoides L., 
Prunus pennsylvanica L., and Pyrus communis L. In these cases the 
experiments were started in August, and there were no heavy rains to 
wash the nitrate into the soil until some time after it was added. The 
analyses of Prunus indicated a small increase of nitrogen in the check leaves 
and a still smaller increase in the leaves from the ringed stem, but the 
gain in the check was so small, only about 6 percent per unit of area, that 
the data are not presented. When expressed as percentage of dry weight, 
there was a distinct lowering in the leaves of the ringed stem, as would be 
expected. The analyses of the maple leaves picked 56 days after the 
nitrate was added to the soil showed no increase in nitrogen even in the 
check leaves. It would seem that all nitrogen absorbed had been taken 
up by other tissues before it could reach the leaves. This might be expected 
at this time of year, since quantities of carbohydrates must have accumu¬ 
lated in the various storage tissues. It is interesting to note that, though 
there was no change in nitrogen as measured per unit of area, the leaves 
from the ringed stems developed a very distinct purplish color, whereas 
the check leaves remained green. When the nitrogen content was expressed 
as percentage of dry weight, there was a distinct lowering in the leaves of 
the ringed stems. 
From the data thus far presented, it seems evident that the ringing 
has reduced the upward transfer of nitrogen and ash constituents. It is 
conceivable, however, that the low content of nutrients in the leaves may 
be due, at least in part, to the retention of these constituents in the stem 
just above the ring, since these tissues have an excess of organic matter, 
the removal of which is prevented by the ring. 
In order to test this point, an experiment was tried with California 
privet (. Ligustrum ovalifolium Hassk.) in which pairs of uniform stems 
were used and both the leaves and the entire experimental stem were 
analyzed. In preliminary experiments it was found that the areas, weights, 
and nitrogen and ash contents of paired leaves of a given stem were very 
nearly equal. One from each pair of the more mature leaves of a given 
stem were removed at the beginning of the experiment, and the remaining 
leaves, together with the stems, were taken at the close. Three to six 
pairs of the younger leaves growing at the tops of the stems were left and 
