THE EOOT. 23 



trees vary much iu tlieir natural tendency to produce 

 fibres. Thus the pear and the apple require frequent 

 transplanting, and often root pruning, to produce that 

 fibrous condition, Avhich is necessary to great fruitfulness ; 

 AvhilsL the roots of tlie paradise apple, used as a stock for 

 dwarf trees, and the quince, are always quite fibrous, the 

 former never, and the latter seldom, requiring root 

 pruning. 



The Spongioles is a term, which was formerly applied 

 to the extremities of the root fibres, it being supposed 

 that these tips were especial organs through which the 

 plant absorbed its food from the soil. Later observations 

 have sliown that the absorbing surface of the rootlet is 

 not at the very extremity, but just back of it ; and that 

 instead of there being a spongiole, or spongelet, the spe- 

 cial ofiice of which is to take up moisture, all the newly 

 formed root surface does this work, in which it is facili- 

 tated by great numbers of root hairs, which are delicate 

 projections from the surface, and so minute as to be only 

 visible by the aid of a microscope. The root fibres are 

 composed of soft, newly formed, delicate tissue, and are 

 exceedingly suscptible of injury. The slightest bruise, 

 or exposure to a dry or cold air, is fatal to them ; and this 

 is the reason why transplanted trees generally receive 

 such a severe check, and so frequently die. If trees could 

 be taken up in such a way that the root fibres could all, or 

 mostly, be preserved, trees would receive no check what- 

 ever. By taking proper precautions, large trees are re- 

 moved in midsummer without a leaf flagging. 



The Groicth of Moats. — The root increases in length 

 by additions to its extreme point only. It does not ex- 

 tend throughout its whole length, as does the joint of a 

 stem. Tliis manner of growth allows it to accommodate 

 itself to the oV)staeles that it meets in its course. The ex- 

 tremities of the roots, at first, consist of cellular tissue 

 only, but soon woody fibre is formed in them, and their 



