44 AGRICULTURE FOR BEGINNERS 



the bark. It could go no farther, and was therefore used 

 by the tree to make at this point an unnatural growth. 



It is, then, the general law of sap movement that the 

 upward current from the roots passes through the woody 

 portion of the trunk, and that the current bearing the food 

 made by the leaves passes downward through the bark. 



EXERCISE 



Let the teacher see that these and all other experiments are performed 

 by the pupils. Do not allow them to guess, but make them see. 



Girdle valueless trees or saplings of several kinds, cutting the 

 bark away in a complete circle around the tree. Do not cut into the 

 wood. How long before the tree shows signs of injury? Girdle 

 a single small limb on a tree. What happens? Explain. 



SECTION XIV THE FLOWER AND THE SEED 



Some people think that the flowers by the wayside are 

 for the purpose of beautifying the world and increasing 

 sti o man's enjoyment. Do you think this is 



true ? Undoubtedly the flower is beau- 

 tiful, and to be beautiful is one of the 

 uses of many flowers ; but that is not 

 the chief use of a flower. 



You know that when peach or apple 

 blossoms are nipped by the spring frost 

 the fruit crop is in danger. The fruit of 

 the plant bears the seed, and the flower 

 FIG. 30. PARTS OF produces the fruit. That is its chief duty. 

 Do you know any plant that produces 

 seed without flowers ? Some one answers, " The corn, the 

 elm, and maple all produce seed, but have no flower." No, 



sty.- 



