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



185 



It is unknown whether or not, under MP 1-2 above, the arcs cor- 

 respond to the inner of the two tip flushes. The two entries under 

 TTP 24-8 above apply to two different side branches. 



3. Two diameter flushes correspond to one tip flush. 



-I tf 



Attention should be directed to TRA i-i and TRP i-i, repre- 

 senting two different genera, which had produced no tip growth by 

 June 28, but which had made diameter growth. In TRA i-i, 1942 

 xylem was an incomplete, but entire, growth layer. In TRP i-i-a, 

 1942 xylem consisted of several short lenses up to three cells thick; 

 in i-i-b, 1942 was a single 100° lens two cells thick; in sections c, 

 1942 was one lens of 45° two cells thick; and in sections d, 1942 con- 

 sisted of two to four cells around the entire circuit. Amount of xylem 

 neither increased nor decreased uniformly along the branch. 



4. Two diameter flushes correspond to two tip flushes per year. 



