KNUDSON: CAMBIUM DEVELOPMENT IN AMERICAN LARCH 285 
was removed. The removal, as before, was made from the south 
side of the tree. The branches were numbered according to their 
position on the tree, the topmost branch being No. 1, and the 
basal branch No. 7. From the individual branches there was 
removed from each season’s growth a cutting; from the topmost 
branch two such cuttings were removed and from the basal branch 
TABLE VIII 
NUMBER OF ROWS OF XYLEM CELLS AND DIAMETER INCREASE OF XYLEM TISSUE IN 
THE CUTTING FROM LATERAL BRANCHES OF TREE E 
Region of cutting on lateral No. of rows of new | Diameter increase 
No. of branch branch xylem cells of xylem 
Below rst whorl 
Below 2d whorl 
Below Ist whorl 
Below 2d whorl 
Below 3d whorl 
Below Ist whorl 
Below 2d whorl 
Below 3d_ whorl 
Below ss whorl 
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Below 7th whor 
Below 1st whorl 
’ Below 2d whor 
Below 3d whor 
Below 4th whor 
Below 5th whor 
Below 6th whor 
Below 7th whor 
_ Below 8th whorl 
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seven cuttings. These cuttings were fixed, sectioned, and pre- 
pared as before. In the following table the figures given refer 
only to the number of cells in the new xylem layer and to the 
diameter of that tissue. The diameter increase over the entire 
tree is represented in DIAGRAM III. 
Ms 
