128 Proceedings of Indiana Academy of Science 
Date Mean length Mean increment 
IEA. Serer chet d Okcorcr ce tts Goren Che Heat ozo < eS —0.01 
livin Aes Artech gels sevel este hte value 38 edeuadeheae) = oe 0.01 
STUY licaene evan om Pvc tale, of pete re yen cna.evevsle. fier ane 1.73 0.00 
Wiealiy gs? Oca aise scars icy aches yom cok «.sieieprdersres WS (5 0.02 
SDrupy Be Otis ee Acre Sons ate hese watcanaPe/ lelehetohersl © 1.75 0.00 
JAGR Ar “a oo ao Doe Ges O60 ane Gb oo ablap. 1.74 —0.01 
BAG CaaS Ole (Se Be oS oe taneeo ney cates re eae O. 0.02 
TSR tap liaigr, cna yogis chs, occete¥s Gite pope AS agsiele IDS {Ko 0.00 
PATE ONES aR) Marc oti et oe, a ines Beso) paar one cei 1.75 —0.01 
INUATIGIE GUS Mkaiaratc minke Hitie.o Coola pig eoe oe = 6 0.01 
Septentberta lege suctevats --aeeaeeatons cacsek@) hey onthe ie: UL Se! —0.02 
Septembers lai cry. wicker serene alerts he) ora i 7! 0.00 
The dogwood shoots which developed from terminal buds were fur- 
ther divided on the basis of whether they were true terminal branches 
or were lateral branches of the pseudo-whorl which develops from the 
terminal bud in the spring. The mean final lengths of these branches 
were determined for each group and for the two groups combined. 
The results are shown in Table 7. 
Table 7. Final mean length of the true terminal branches and of 
lateral branches from terminal buds in dogwood. 
Number of 
Group Type of shoot shoots measured Mean length 
1 True terminal 12, 4.40 
1 Lateral 21 7.44 
2 True terminal 6 .54 
2 Lateral 13 2.00 
All True terminal 18 oe la 
All Lateral 34 Ban 
DISCUSSION. 
Since the data secured come from a limited number of trees and 
shoots under different and varying environmental conditions it will not 
be possible to reach conclusions concerning the normal seasonal course 
of the growth of tree twigs under uniform outside conditions. Fur- 
thermore, it is probably not possible to obtain such curves in humid 
regions without recourse to irrigation unless an exceptionally good year 
should happen to be found, or if the observations should be extended 
over a sufficiently large number of seasons to equalize variations in 
rainfall. Even then one season’s observations under irrigated condi- 
tions ought to be more reliable. The present season’s rainfall was 
fairly uniform, and yet the growth curve seems to have been affected 
rather definitely by rainfall variations. However, the variations in the 
conditions give certain advantages in interpretation which would not be 
secured were the conditions uniform. 
The curves all show the same general type. The growth rate at 
first is slow, it increases to a maximum, and then decreases to zero as 
the season advances. The initial slowness of growth is not very clearly 
indicated by the data for the shaded dogwood bush, nor for the shaded 
shoots on peach tree No. 2, but it would doubtless be more evident if 
