l82 



General Botany 



surface. Plants whose root systems are a combination of the 

 two obviously have the best possible arrangement with reference 

 to soil water. 



J. E. Weaver 



Fig. io8. Vertical section showing the extent of the root system of mature corn grown at 

 Peru, Nebraska. The section is divided into one-foot squares. 



Corn, cabbage, mock orange, blue-grass, and buffalo grass are 

 examples of shallow-rooted plants. Cottonwood, oak, hickory, 

 alfalfa, sugar beet, and California poppy have long tap roots which 

 may penetrate to the water table. Many of our tall grasses, par- 

 ticularly the '' bunch grasses," have great masses of long, fibrous 

 roots — the underground part of the plant being far greater than 

 that above ground. However, the form of the root system of 

 any plant may be greatly modified by soil conditions. 



