THE ^/aERICp BDTpiST. 



Vol. IV. BINGHAMTON, N. Y., JANUARY, 1903. No. 1. 



BARK. 



BY PROF. W. W. BAILEY. 



TREE is known as well by its bark as by its general 

 ^ pose or the character of its foliage. The expert 

 woodsman, who probably has no botanical knowledge 

 whatever, will tell you, not only the generic but often the 

 specific and varietal kind of tree. Thus, with the genus 

 Ouercus, he will say whether it is the white, the swamp 

 white, the red or the pOvSt oak ; or, in the case of hickory, 

 whether one has shell-bark or pig-nut. The latter, how- 

 ever, is an easy case. Trees generally, stick to their uniform 

 — but now and then, one is deceived. The chestnut and 

 some other trees, wear different clothes in age from what 

 they showed in youth. Ayotmg chestnut is quite a dandy, 

 with a smooth pattern to his garments. The old fellow 

 ceases to have his wrinkles ironed out. 



We think of bark merely as the protecting envelope of 

 the tree, but its structure is often complex and its func- 

 tions various. It has, too, an individual and instructive 

 history. At first it consists of a mass of cells hardly to be 

 distinguished from the ground tissue, except that the cells, 

 when exposed to light, turn green. This shows the pres- 

 ence of chlorophyll, and, indeed, at this time stems may 

 function like leaves. But as the cambium at the growing 

 season, jjroduces wood within and bast without, a similar 

 increa,se or growth takes place in the bark. To replace 

 exfoliated parts — new tissue is formed or at least set apart 

 as bark. The inner portion, next the wood, developes the 

 so-called inner bark. Here one finds the bast cells, long 

 and tough and flexible. 



Next comes the cellular envelope or green layer, which. 



