68 



GLIMPSES IXTO PLAXT-LIFE 



skin, called the epidermis, and over that is the root- 

 cap shaped like a thimble formed of small cells. 

 As they are worn away outside and become dead 

 tissue, owing to friction with the soil, the cells are 

 constantly being renewed from \\ithin. The root 

 is thus enabled to grow and perform its part in 

 maintaining the life of the plant. The presence of 

 this root-cap and the ab.sence of 

 leaves are the marks b>- which a true 

 root is known and distinguished from 

 an underground stem. With a small 

 lens one can see this extinguisher-like 

 cap protecting the extreme point of 

 the root, and it is well to examine a 

 sKCTiox OF variety of specimens, and -see how they 

 differ slightly in size and shape. 

 The one especial office of the root is to absorb 

 liquid nourishment from the soil for the benefit of 

 the plant, and, as I have already explained, this is 

 done mainl)' through the hairs which grow upon 

 the fibres of the roots. For instance, there is no 

 absorption in old tree-roots, such as we sometimes 

 see above the ground, nor in carrots, turnips, and 

 parsnips, but thrown out from such bulbous jjlants 



