46 THE ROOT. 



drawn by nature by which we may determine the precise 

 point where the stem ends and the root begins. The fibres 

 extend from one to the other, and the union is made by a grad- 

 ual conversion of the one into the other. The seat of vital- 

 ity has been supposed to be in the neck, but numerous exam- 

 ples will readily occur to the student disproving sucli a hypo- 

 thesis. The neck in many plants may be removed and the 

 roots and stems will still survive by proper attention ; pro- 

 ving not only that the neck is not the seat of vitality, but 

 that there is no such single point which if destroyed, the 

 plant necessarily perishes. 



The principal differences between the root and stem are, 

 1st, that the root is destitute of pith, and 2d, the true spiral 

 vessels are not developed in it ; 3d, there are generally no 

 regular huds formed on the roots ; 3^et they are capable of 

 putting them forth under favorable circumstances, as may be 

 seen in the shoots that spring from the roots of the Peach, 

 Plumb, Cherry, and Poplar ; 4th, Stomates are not found in 

 the bark of the roots. 



In other respects the root does not differ from the stem, 

 and we have no doubt that the differences above noticed are 

 in a great degree owing to the situation of the root. The 

 moist, resisting medium in which it is placed produces the va- 

 riation rather than anv real difference of organization. Stems 

 when exposed to different influences change their type of or- 

 ganization to fit themselves to the different circumstances in 

 which they are placed. 



The most important distinction on which our idea of the 

 root and stem should be founded, is contained in the first part 

 of our definition, that the root is the descending part of the 

 axis of a plant. If it descends it is a root, and if it ascends 

 it is a stem ; we mean, of course, when they meet with no 

 physical impediment. 



54, The forms of roots are various, and receive different 



names in the descriptions of plants, 

 which it will be our next object to 

 point out and explain. Although vari- 

 ous divisions have been made by diffe- 

 rent Botanists, yet great discrepancy 

 exist among; them. We shall describe 

 those only, which we think most ira- 

 portant, and the most common forms. 

 1st. Branching Root, or Radix ra- 

 mosa. Fig. 19. These roots are such 

 as subdivide in the earth in a manner 



