CHAPTER VI. 



ROOTS AND EOOT-STOCKS. 



The study of root systems is accompanied with more or less dif- 

 ficulty and expense, and this, no doubt, accounts for the small 

 amount of work done along this line. 



Two methods have been employed to obtain the complete root 

 system of growing plants. That used by Ten Eyck is perhaps the 

 most satisfactory, although tedious and expensive. It consists of 

 excavating about a plant and enclosing the whole mass of earth 

 containing the roots in a cage of wire netting. Steel rods are 

 thrust through the cage horizontally to prevent the roots from 

 breaking. The soil is then carefully washed away leaving the roots 

 very nearly in their natural position. 



The other method, employed by a Russian investigator, Rot- 

 minstror, has given quite satisfactory results. The plants are 

 grown in soil made up of top- and subsoil. This is placed, the sub- 

 soil below and the topsoil above, in boxes 1 in. wide, 20 to 40 in. 

 deep and 20 to 40 in. long. These boxes are placed in the ground 

 level with the surface. The plants are then grown in these boxes 

 and removed when desired, the soil carefully washed away and 

 the entire plant transferred to paper. 



Fig. 504. Root-stocks or rhizomes of Quack Grass (Agropyron repens). These 



root-stocks are sometimes more than four feet long. 



(Photographed by Stevens.) 



