50 THE VEGETATIVE FUNCTIONS OF PLANTS 



The tip of the root is covered by a root-cap (Fig. 37), 

 composed of cells that serve to protect the delicate tip as 

 it grows through the soil. In some cases, as in the 



FIG. 36. ^Germinating seeds of white mustard, showing development of 



root-hairs. 



water-hyacinth (Figs. 38 and 39), the root-cap is so well 

 developed that it may be easily seen with the naked eye, 

 and quite readily removed and replaced. Root-hairs are 

 never found on the region covered by the root-cap. 



