THE ROOT THE FORMS OF ROOTS 



33 



an axis from which the side roots may branch. The side 

 or spreading roots are usually smaller. Plants that have 

 such a root system are said to be tap-rooted. Examples 

 are red clover, alfalfa, beet, turnip, 

 radish, burdock, dandelion, hickory 

 (Figs. 32, 33). 



A fibrous root system is one that 

 is composed of many nearly equal 

 slender branches. The greater 

 number of plants have fibrous roots. 

 Examples are many common 

 grasses, wheat, oats, corn. The 

 buttercup in Fig. 34 has a fibrous 

 root system. Many trees have a 

 strong tap-root when very young, 

 but after a while it ceases to ex- 

 tend strongly and the side roots 

 develop until finally the tap-root 

 character disappears. 



Shape and Extent of the Root Sys- 

 tem. The depth to which roots 

 extend depends on the kind of plant, and the nature of the 

 soil. Of most plants the roots extend far in all directions 

 and lie comparatively near t/i? surface. The roots usually 

 radiate from a common point just beneath the surface of 

 the ground. 



The roots grozv here and there in search of food, often 

 extending much farther in all directions than the spread 

 of the top of the plant. Roots tend to spread farther in 

 poor soil than in rich soil, for the same size of plant. 

 The root has no such definite form as the stem has. Roots 

 are usually very crooked, because they are constantly 

 turned aside by obstacles. Examine roots in stony soil. 



FIG. 34. A BUTTERCUP 

 PLANT, with fibrous roots. 



