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14 BULLETIN 1185, U. S. DEPARTMENT OF AGRICULTURE. | 
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| leaf scars also overlap the adjoining epidermis at_each node, so that the 
Hh waterproof union includes epidermis, fiber bundles, and w ooden core 
The leaf scars cling persistently 
until toward the very last stage in 
retting. Figure 10 shows on the 
left a piece of unretted cortex 
spread out flat; note the distribu- 
tion of leaf scars, represented by 
small black, triangular to heart- 
shaped spots. In the center the 
partly retted portion of a flax stem 
shows how, after breaking, the 
shives cling to the cortex at the 
nodes where the leaf scars occur. 
On the right is shown a piece of 
cortex that is almost through ret- 
ting; note that the broad or coarse 
places in the fiber center about the 
leaf scars. Examinations were made 
of samples of good to medium grade 
fiber from Belgium, Holland, Japan, 
Chile, Ireland, and Canada. In 
the best grades of fiber which had 
been well retted no leaf scars could 
be found. In the underretted and 
coarse grades of fiber leaf scars 
were found where there were coarse 
places in the fiber. 
Figures 11, 12, and 13 give some 
idea as to the nature and the per- 
sistence of the leaf scars. Figure 
11 shows a piece of unretted cortex 
enlarged ten times. The fiber bun- 
dles show only as very dark strips. 
The structure of the epidermis is 
obscured by the tissues underlying 
it. The bundle traces are not visible 
in the leaf scar. An undeveloped ~ 
bud is shown in the axil above the 
leaf scar. In Figure 12 retting has 
proceeded far enough to separate the 
wooden core from the cortex, but the 
cortex is almost intact. The cel- 
lular structure of the epidermis 
shows, as part of the underlying 
tissue has been destroyed. The 
| re. 9._Chanbes an dhe color of fax 2eal scar has been partly: dissecnem 
I stems during the process of retting. A away from the rest of the cortex. 
i Seas colnn de, (asia again as the Note how persistently the branches 
| last stages of retting. The light-colored of the fiber bundles cling to the leaf 
HII stem on the right is almost retted. : =) 
scar. Figure 138 shows a _ leaf 
scar and the surrounding tissue as it appears when retting is 
almost complete. The retting has removed nearly all the pa- 
