- 
1888. } BOTANICAL GAZETTE, 285 
tissue where it joins the regular periderm. This is shown in 
fig. 15, 6. This breaking is prevented at first by the cells 
along these lines forming new walls at such angles as to form 
a fan-like spreading, large enough to accommodate the rap- 
idly growing wing. The rapidity of growth, at first greater 
in the center of the wing, appears to gravitate toward the 
edges, and the break occurs. Both sections of the wing are 
now free to be shoved out by the rapidly growing phellogen. 
In the meantime the fissure in the middle, originating from 
the lenticel opening, increases till it reaches in many cases 
quite down to the primary rind. Toward the fall, about the 
middle of September in the examples studied, there are 
formed several layers of plate cells, extending around the 
Whole stem. When growth is resumed in the following 
spring, the formation of cork is limited strictly to the phello- 
gen under the wings; its rapid growth breaks the bands of 
ber of annual layers of cork did not agree wi 
of woody layers of the stem. 
cork were found, where only three o 
tainty be detected. It is impossibl 
Whether two rings of cork had been added each year, Or 
Whether the annual marking off of the wood had failed in the 
later years of growth, as the last rin of wood which was 
Plainly marked off was about the width of both the other ot 
rapid. 
e to say, in this case, 
and one and a half 
Cc These large witgs, 
i st C stems 
See found on lateral branches, occur 1n most ie on a 
th Ich have closed their growth in length. Rie a 
Whose 2rowth in length is prolonged from year oO j 
