NO. I GROWTH LAYERS IN TREE BRANCHES — CLOCK ET AL. 



283 



This branch contains not only a sharply bordered growth layer for 

 each tip flush but also other growth layers for which there are no 

 visible tip-flush additions. In other words, the activity, or lack of it, 

 in the cambium does not always find its counterpart in the growing tip. 

 Such nonconformity has been well illustrated previously and is further 

 shown in the following branches. 



4 a 12 16 



t I I I I I 1 1 I 



Fig. 50. — Secondary leader of Pinus taeda (Con T 1-4) with branches, Con 

 T 1-6 to I -10, to show annual increase in diameter flushes and tip flushes. Cross- 

 bars represent terminal bud scale scars. Capital letters refer to unstained blocks 

 removed from leader and branches ; small letters refer to position of stained 

 sections. Figures opposite letters give the number of growth layers in the sections 

 represented by the letters. 



Con T 1-8 (1941-1942) 



a. 3 psce — 3 tfs — 2 years. 



b. 2 dee — 2 tfs — I J years. 



c. I dee — I tf — I year. 



