there are numerous yet smaller structures which we do not see at 

 all when we handle the plant so roughly. 



3. The rootlets are clothed ivith hairs {root-hairs) ivhich are 

 very delicate structures. — Next we will carefully germinate some 

 radish seed so that no delicate parts of the root will be injured. 

 For this purpose we simply sow a few seed in packing-moss or in 



the folds of some black cloth, being careful to 

 keep them moist. In a few days a seed has 

 germinated, the root has grown an inch or two, 

 and branched once or twice, perhaps. Lift the 

 moss careful!}-, or open the folds of the cloth. 

 Figure 2 shows what may be found. Now 

 notice that at a distance of about a quarter of an 

 inch from the tip, the root is covered with a 

 delicate fringe of hairs. The}' are actually hairs, 

 that is, root-hairs. Touch them and they col- 

 lapse, they are so delicate. Dip one of the 

 plants into water, and when removed the hairs 

 are not to be seen. The water mats them to- 

 gether along the root and they are no longer 

 evident. No wonder we cannot see root-hairs 

 well when a plant is pulled out of the soil, 

 be it done ever so carefully ! These delicate 

 root-hairs clothe the young rootlets, and we can 

 hardly estimate what a great amount of soil is thus brought into 

 actual contact with the plant. The value of this contact we 

 shall soon see. Root-hairs are not young roots. 



4. The rootlet and the root-hair differ. — The rootlet is fleshy in 

 its way, — a solid compact structure. The root-hair is a tubular 

 plant cell, that is, a delicate little tube, within the cell wall of 

 which is contained living matter (protoplasm) ; and the lining 

 membrane of this wall permits water and substances in solution 

 to pass in by a very interesting physical process. Being long 

 and tube-like, these root-hairs are especially adapted for taking 

 in the largest quantity of solutions : and they are, in fact, the 

 principal means by which plant-food is absorbed from the soil, 

 although the surfaces of the rootlets themselves do their part. 

 Water-plants do not need an abundant system of root-hairs, and 

 such plants depend largely upon their rootlets. 



2. Root-hairs of 

 radish. 



