Tni<] m)OT. 35 



tached tx) the place of its irrowtli. The root in its ix«''i"^'ral ap- 

 pearance resembles tlie stem ; and wlien taken too-othor they 

 have been, not unaptly, compared to two cones united by their 

 bases. Both take their origin from the same vital points, yet 

 under the influence of the vital power they seem to be endowed 

 with opposite propensities, — one growing- upward, seeking light 

 and air, the other with an equal impulse forcing its way down- 

 ward, and burying itself in the eaith. We may consider the 

 plant as endowed with opposite polarities ; one |X)le uniformly 

 taking the direction of gravity, the other as \niiformly the oj)- 

 posite direction. The surface of the earth may, in general, be 

 considered the equator of this living magnet, and the zenith 

 and nadir its poles. 



Although we speak of Root and Stem being joined at a point 

 called the neck, still there is no line of demarkntion drawn by 

 nature by which we may determine the precise point where the 

 stem ends and the root begins. The fibers extend from one to 

 the other, and the union is made by a gi-adual convei'sion of the 

 one into the other. The seat of vitality has been supposed to 

 be in the neck, but numerous examples will readily occur to the 

 student disproving sudi an hypothesis. The neck in many plants 

 may be removed, and the roots and stems will still survive by 

 pro]>er attention ; proving not only that the neck is not the seat 

 of vitality, but that there is no such single point which if de- 

 stroyed, the plant necessarily perishes. 



66i The principal differences l)etween the root and the stem 

 are, — 1st, the root is destitute of pith, and 2d, the true spiral ves- 

 sels ai^ not developed in it, heiice no medullary sheath : 3d, 

 there are generally no regular buds formed on the roots; yet 

 they are capable of putting them forth under favorable circum- 

 stances, as may be seen in the shoots tliat s])rino- 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 

 the difierences 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 variation, rather than any real dilfirence 

 of organization. Stems, when exposed to different inlluences, 

 change their type of organization to fit themselves to the dif- 

 ferent circumstances in which they are placed. 



The most imjxtrtant distinction, on which our idea of the root 



To what may the stem and root be compared ? — G(>. AVhat arc the difter- 

 *inces between root and stem? To what may tlicir diflerctices be in some 

 manner ascribed ? What is th \ most important distinction ? 



