THE WORK OF STEMS 105 



which we find when we remove the bark from a tree or 

 twig. It is here that all growth takes place and that new 

 sieve tubes or water-carrying vessels are formed as the 

 plant has need of them. When we reach the subject of 

 grafting, we shall have to, remember that the cambium 

 layers of the root and the twig must be actually touching 

 each other or the two will not grow together. 



82. Rope, Twine and Linen Material. — We can not 

 conclude our study of stems without learning something 

 of the spindle-shaped cells, called bast fibers, which often 

 make up a part of the outer portion of the stem. They 

 give it strength and flexibility. 



The bast fibers of the hemp and flax, which are grown 

 in different parts of the United States ; of the Manila 

 hemp, which is a small tree of the banana family found in 

 the Philippines ; and of the century plants of Mexico 

 yield us our chief supply of rope, twine and linen thread 

 material. 



The stems of the hemp and flax are allowed to soften 

 by partial decay in the field, or hot water is used, and the 

 wood removed, leaving the long fibers, which are bleached 

 and spun into the material desired. These fibers may be 

 found in the wild hemp nettle which grows along creeks 

 and in low places. If the stem is broken in winter, the 

 long strands of bast fibers may be secured and woven or 

 braided. 



QUESTIONS 



1. Name three functions of stems. 



2. Name three forms of stems. 



3. Name two weeds with prostrate stems, two with climbing 

 stems, and two with erect stems. 



4. How does water from the soil reach the leaves ? 



5. Why does a callus form above, but not below, a cut in 

 the bark of a tree? 



