374 



LIFE ON THE EARTH 



make the same observations 

 and experiments on the stem 

 of a small seedling palm tree. 



Experiment 116. Ex- 

 amine a piece of the growing 

 young stem of a willow, apple 

 tree or other woody stem 

 that shows several leaf scars. 

 Is the arrangement of the 

 leaves the same as in the corn 

 stalk? Cut a cross section 

 of this stem and examine it. 

 Does it resemble the cross 

 section of the corn stalk? 

 Strip off a piece of the bark 

 and compare it with the rind 

 of the corn stalk. Examine 

 carefully the smooth, slippery 

 surface of the wood just be- 

 neath the bark. This is the 

 cambium layer. 



Examine the firm wood 

 beneath this layer. Where is 

 the pith in this stem? With 

 a lens you may be able to 

 see lines radiating from the 

 pith to the circumference of 

 the stem. These are called 

 the pith rays. Cut a length- 

 wise section of the stem and 

 examine it. Are there any 

 fiberlike bundles as in the 

 corn stalk? Cut off a piece 

 of the stem already examined 

 having the bark on it, or a piece of sunflower stem, and place the 

 end of it in colored water. Allow it to remain for some time and 

 .then cut a cross section above the point where it was in the water. 



A PINE TREE 

 Notice the erect position of the stem. 



