MISSOURI BOTANICAL GARDEN BULLETIN 165 
silver maple trees. Four to seven twigs were measured on 
each tree, only healthy unbroken ones being used. As might 
have been expected, different twigs on the same tree showed 
about the same proportions of growth for the four years. The 
following data are typical: 
GROWTH OF SILVER MAPLE TREES FOR 1919-1922 
(in inches) 
1919 1920 1921 1922 
11 9.5 6.5 6 
6.5 8.5 5.5 3.5 
7.5 8.0 6.0 4.0 
11 8.0 8.0 3.5 
9.5 12.0 9.5 8.5 
More surprising, however, is the fact that all the trees 
showed practically the same proportions of growth for the 
four years. In spite of the fact that some were small and 
some large and that they came from the most diverse situa- 
tions, all but one showed the greatest growth in 1920. To 
make the data directly comparable the year in which the tree 
made the greatest growth is recorded in the following table 
as 1, the second greatest as 2, etc.: 
COMPARATIVE GROWTH OF TEN SILVER MAPLE TREES 
Tree No | 1 2 3 4 5 6 7 8 9 10 
1919..... 2 2 2 2 2 2 2 4 1 2 
1920..... 1 1 1 1 1 1 1 1 2 1 
1921..... 3 4 4 4 3 3 4 3 3 3 
1922..... 4 3 3 3 4 4 3 2 4 4 
The following figures from a few trees in Webster Groves 
show that the same general conditions prevailed over a fairly 
large area: 
COMPARATIVE GROWTH OF SOME WEBSTER GROVES TREES 
FOR 1919-1922 
Tree No. 1 2 3 4 
CTT aor ae 1 1 1 
TO20 cea 1 2 2 2 
ab Sr aearaere 3 | 4 4 
oh eee 4 4 3 3 
