38 



ROOT-CAP. 



[CIL III 



main body of the root ends at M, and the part that gives 

 the conical form seems to be made of less dense material. 



FIG. 14. 



A ROOT- CAP DIAGRAMMATICALLY REPRESENTED. 



R, root. M, meristematic region. C, root-cap. 



These appearances, somewhat obscurely seen with the 

 naked eye, correspond to actual and important facts. 

 The cap-like part G is a structure highly characteristic 

 of roots, a region of the root of great interest and im- 

 portance, known by the name of root-cap. The surface 

 of the root-cap is slimy because the most outward 

 of its constituent cells are constantly becoming dis- 

 organised, and in the natural life of the bean they are, as 

 they die, rubbed off against the resisting soil penetrated 

 by the root. In spite of this wear and tear the root-cap 

 is not entirely worn away : this should suggest that, like 

 the skin on the human hand, it is renewed underneath as 

 it is worn away outside. This is the case, and it is at the 



