130 Proceedings of Indiana Academy of Science 
Owing to the lag of the seasonal curve of temperature the days of 
given length in spring are much cooler than days of the same length 
in the fall. 
This study has suggested a few interesting points concerning the 
dogwood which do not have to do directly with the growth rate. The 
dogwood is well known as a shade enduring tree. The quickly declin- 
ing growth rate of the shaded tree in this study suggests that this 
ability on the part of the dogwood is not due to an unusual power to 
grow in the weak light of the forest, but rather to an ability to grow 
for a few weeks in the spring and then spend the entire remainder of 
the season slowly storing up food for another few weeks’ growth the 
next spring. 
Another interesting fact, which is shown by Table 7, is that, con- 
trary to the condition in most trees, the terminal shoot in the dogwood 
is shorter than the laterals of the same season’s growth. Each ter- 
minal shoot, as it starts growth in the spring, produces one or more 
very short internodes and sends out one or two lateral branches from 
each of the closely spaced nodes.. There are thus from one to about 
six laterals produced in an arrangement which simulates a whorl. The 
measurements mentioned above show that the average final length of 
these laterals exceeds the final length of the terminal. Additional ob- 
servations (without measurements) show that in upright, unshaded, 
rapidly growing stems the terminal exceeds the laterals, but that in 
the case of stems growing at an angle the lowermost branch grows the 
longest and becomes the leader, while the rest of the branches decrease 
in size till the innermost (or uppermost) one is reached, and the ter- 
minal is still smaller. Thus every year a new branch becomes the 
leader and each successive true terminal finally assumes the role of 
a minor branch. The result each season is to produce a more or less 
eccentric umbel shaped group from each terminal bud which opened 
that spring. 
SUMMARY. 
A number of woody shoots were measured during one season’s 
growth period. The results showed an initial slow growth rate, which 
then increased to a maximum, and later decreased to zero before the 
temperature had dropped to the point at which growth started in the 
spring. The slow initial rate in this case is believed to have been due 
to the cool weather at the time. The onset of the decrease in growth 
rate is believed to be due to a decrease in available moisture for at 
least part of the trees, and it is therefore considered impossible to get 
dependable curves for the normal course of a season’s growth in tree 
twigs without having recourse to irrigation. For one of the trees and 
for some shoots on others the onset of the decrease in growth rate is 
believed to be due to shading, and it is suggested that in all cases the 
variation in relative length of night and day may have influenced the 
course of the cycle. The ability of the dogwood to live and develop in 
shady situations seems not be due to an ability to grow in poor light 
but rather to an ability to endure shade most of the season and at the 
same time to store food slowly for use in a spurt of growth in the fol- 
