1915] BROW N—PINUS STROBUS 209 
It follows from table D that on May 4 cell division was going 
on in all parts of the bole on the south side of the tree, with the 
exception of the terminal leader. It was farthest advanced in 
cuttings IT and III, as might be expected, because the last formed 
annual ring was thicker here than in the basal cutting. 
TABLE D 
EXTENT OF GROWTH IN TREE 1, May 4, 1913 
- Number of Amount of 
<ee tracheids | lignification memneks 
x hea leader, 1 year’s 
ee gab cen vere ea a None None Phloem active; no cell 
; division 
I. Same, 2 years’ growth. . 1-2 | None Same as above 
Il. 44 feet above ground . 12-15 | 1-3 tracheids) New phloem elements. 
cell division 
IIT. 33 feet above Serie 12-15 | 1-2 tracheids| Same as above 
IV. 5 feet above eatera 1o-12. | None Same as above 
The branch cuttings were made on a branch which ran out 
some 20 feet in a southeasterly direction at a distance of 13 feet 
above the ground. Five cuttings were taken at intervals of about 
4feet. In cutting I (beginning from the tip) no tracheid formation 
was evident. In cuttings II and III tracheid formation was in 
progress, while in IV and V (basal) enlargement of the tissues had 
occurred, but no cell division. Cell division in the branches was 
similar to that in the bole, but more sluggish. It begins back of 
the branch leader and is most tardy in the base and leader of the 
branch. Which of the last is the first to exhibit growth depends 
on the length and vigor of the branch. 
Numerous other observations were made on trees of different 
ages and different localities. It was found that cell division may be » 
in progress some time in the upper portions of a tree while it is 
totally lacking below. This applies especially in old mature trees 
in closed stands, where growth is proceeding very slowly. Further, 
in general cell division first begins on the south side of the tree and 
in the basal portions. This peculiarity, due apparently to insola- 
tion, has also been observed in some cases in pitch pine (r). 
It was noted in reviewing the literature on tree growth, that 
some (14) have attempted to correlate growth awakening with 
