8 MANUAL FOR SUGAR GROWERS. 



evident : roots increase in length only at their ends, 

 so that the end always consists of young and deli- 



FIG. 3. Eootlet, with root-hairs and root-cap. 



cate cells which must be protected from injury 

 while being thrust through the soil; the root-cap 

 therefore affords protection to the delicate cells 

 lying beneath it. The root at intervals throws out 

 branches which from their earliest appearance are 

 clothed with a root -cap, and root -hairs soon de- 

 velop near the end. It will easily be seen why it is 

 impossible for roots to lengthen except at their ex- 

 tremities, for the root-branches imbedded in the soil 

 would be torn off if the main root grew in length 

 in the parts between their respective bases. * 



* In taking up a rootlet for examination for root-hairs and 

 root-cap, care must be taken in removing the soil, as these organs 

 are very delicate. The examination of rootlets growing under a 

 flat stone is often highly satisfactory. 



