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THE SEEDLING AND YOUNG PLANT.
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come thinner (Fig. 21), and the same is found as it tails off below; changes in structure also appear in the leaves.
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Fig. 18.—Longitudinal radial section of the cortex and phloëm of oak. References as in Fig. 17. (Luerssen.)
The first noticeable change is the diminution in the number of wood fibers and the presence of narrow
