THE ROOT 25 



part, are completely free from root-hairs. When a very 

 young seedling is pulled up from out of sandy soil it 

 frequently happens that a considerable quantity of sand 

 remains attached to the root, owing to the root-hairs 

 adhering firmly to the grains of sand with which they 

 were in contact. 



The end or tip of a root is soft and tender, making 

 one wonder how so delicate a structure is able to thrust 

 itself through the hard, rough soil. Careful examination 

 will show that the tip of every root is covered with a 

 little cap or shiejd which serves to protect the point 

 from injury. This root-cap is, in many plants, not very 

 easy to see without the use of a lens, but may often 

 be observed in roots growing in water, for instance, 

 those of the frog's-bit, duck-weed, etc. The screw-pine 

 (Pandanus), to be seen at many florists and in almost 

 every botanic garden, throws out a number of roots 

 from its stem. These roots grow downwards towards 

 the ground, and, if their tips are examined, they will be 

 found to be covered with well marked root-caps. These 

 illustrate remarkably well the nature of the appendage to 

 be found at the extremity of most roots, including even 

 their finest and most minute branches. 



Roots usually grow down into the soil, throwing out 

 numerous branches, and permeating the soil with a 

 network of fine rootlets, each provided with root-hairs 

 and terminating in a root-cap. The main root exhibits 

 a strong tendency to grow vertically downwards, in 

 response to the pull of gravity. This can easily be 

 .proved by placing a growing seedling so that the main 

 foot lies horizontally. If this is done it is found that 



