52 



THE VEGETATIVE FUNCTIONS OF PLANTS 



48. Relation between Root-hairs and Soil. — If young, 

 active roots are removed from the soil, thoroughly rinsed 

 in water, and examined with a compound microscope 

 at the zone of root-hairs, it will be seen that tiny par- 

 ticles of soil have adhered so closely to the cell-wall of 



Fig. 39. — Water-hyacinth {Eichornia crassipes). Photomicrograph of 

 a longitudinal section of a root, showing the mode of origin of lateral roots 

 (i.e. endogenous), a, b, c, lateral roots; r. t, root-cap. 



the hair that they were not washed off; in fact, they can- 

 not be removed without tearing the hair. They appear 

 to be imbedded in the cell-wall (Fig. 42). We thus 

 learn that the relation of root-hairs to soil particles is 

 very intimate. 



