64 



TllK rKlXCIPLES OV AGUICULTUKE. 



iiudistiii'Lcd contact with the soil. In some cases the tip 

 of the root is ])rovided witli a kind of caj), or shiekl, to 

 protect it from injury as it forces its way through the 

 soiL 



The Number and Extent of Roots. — The process of sul)- 

 dividing and muhiplying small roots goes on to a greater 

 extent than is generally supposed. 

 Rich soil in the vicinity of the 

 roots of some plants becomes com- 

 })lctely filled with hair-like root- 

 lets. Sometimes these are so 

 small as to re(piire the aid of a 

 microscope to detect them. 



When a plant is pulled from 

 the soil, these fillers are mostly 

 broken off, only the larger roots 

 remaining attached to the stem. 



The entire length of all the 

 roots of a jdant is sometimes 

 almost incredible. In the case of 

 barley, oats, and wheat, gi-owing 



Jfairs aiul roof-cap {a), magni- jj-, j-ich, mclloW Soil, i( luiS bcCn 



found that the total length of all 

 the roots of one ])lant will amount to from one hundred 

 to one hundred and fifty feet. 



Under favorable conditions, roots sometimes descend 

 to a great dei)th. In deej), mellow soil, the roots of most 

 agricultni'al plants reach a de])th of sevei-al feet. The 

 roots of Indian coi-u, whit'h in common soil do not exicnd 

 more than two or three feet below the surface, have been 

 known to ])enetrate into the earth to a de])th of fifteen 

 feet. Clover roots have been traced to a depth of eight 

 feet, 



Extremity of a Rootlet of 

 Maple. 



