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. 
