102 



SOILS AND PLANT LIFE 



Procedure. — Wash the dirt from the roots of a com 

 plant and of a bean plant, each about six or eight inches 

 high. Put the two plants in a glass of water containing 

 a few drops of red ink. After an hour remove them, and 

 with a razor blade cut each plant off at the lower end of 

 the stem. Make a thin section of the stem at this point, 

 and examine it with a hand lens to see where the water 

 has moved upward. Keep cutting thin cross sections 

 up the stem until you reach the point where only the 

 water-carrying tubes are stained. 



A common house plant, the Sultana, has a very clear 

 stem, and the colored water may be watched as it moves 

 upward through it. Either the narcissus, or the Chinese 

 sacred lily, which you have probably grown in water in 



the schoolroom, may have 

 its blossoms colored by add- 

 ing dye or ink to the water 

 in which it stands. 



Conclusion. — Describe 

 briefly how the water-carry- 

 ing tubes differ in arrange- 

 ment in the com and bean 

 plants. 



Annual rings. 



78. How to tell the Age 

 of a Tree. — In the spring, 

 when there is an abundance 

 of water, the water-canying tubes are very large. As the 

 season advances and the rainfall becomes less, smaller and 

 smaller tubes are made, until in the fall they are so small 

 and compact that they look like a ring of denser, harder 

 wood. In trees, therefore, which grow from year to year, 

 this circular line between the small water-carrying tubes 

 of the fall and the large ones of the spring is so plain that 



