The Delvers in Darkness 



117 



them is a tube. As the life of the plant goes on, 

 the older root-hairs nearer to the upper end of 

 the root fall away, and young ones grow out 

 nearer to the root-tip to carry on the work. 



Roots grow as bank accounts and strings of 

 beads do, by getting more and more added to 

 them ; and the part that was added last is always 

 at the end. In growing time the tip of every root- 

 let is quite new and very 

 tender, yet it is just this 

 tender part which must 

 dig onward through the 

 earth. 



The root-tip would 

 be sadly bruised if it 

 were not protected. So 

 on its very tip every 

 root wears a tough little 



thimble, called the root- 

 Fig. 30. The tip of a root much 

 magnified, showing the root hairs caD (riff. "^O). 

 and the root cap. f \ a J / 



The root-hairs 

 which are tubes, reach in between the grains of 

 earth after water, and find it even in dry places; 

 for when the soil has been drained of all the water 

 that will run out of it, there is still a wet film 

 clinging about every single grain. 



Down where the root-hairs live there is gen- 

 erally enough water, in spring, to fill all the spaces 

 between the earth grains. In fine earth there are 

 more grains to be wrapped around with water 



