THE ROOTS OF VASCULAR PLANTS. 213 



organs by tendrils, is either very rare, or perhaps does 

 not exist ; I have never seen, at least, any but doubtful 

 examples. But the abortion of roots or radiculesj en- 

 tirely or in part, is a frequent phenomenon, and one 

 vehich often deranges their symmeti'y of position. 



Notwithstanding the numerous differences which we 

 have enumerated between roots and stems, there are 

 found some remarkable points of connexion between 

 these two organs. Thus, for example, it is often diffi- 

 cult to fix with precision the point where the stem 

 commences and the root ends. Modern authors all say 

 that it is where the lobes or cotyledons are found at the 

 period of germination : but this rule is evidently false ; 

 the cotyledons are leaves, and are always placed upon 

 the ascending part or stem ; the original neck is always 

 situated below the cotyledons. By only viewing the 

 germination of the Bean, this assertion is demonstrated. 

 We shall revert to this, when we speak of the structure 

 of the embryo. 



A second circumstance, which has induced naturalists 

 to admit the pretended identity of roots and stems, is 

 the facility with which one of these organs gives origin 

 to the other. Every time that in any part of the sur- 

 face of a plant there is a stagnation of the juices, new 

 productions are developed, as if these stagnant juices, 

 meeting with latent germs, nourished them and obliged 

 them to grow. If this part be surrounded by moist soil, 

 or protected from the air and light, the new production 

 is a root ; if it be exposed to the air and light, it is a 

 stem or branch. These principles are equally true, 

 whether they be applied to the roots or stems, to the 

 new productions which are formed naturally or artifi- 

 cially. Thus, if the extremity of a root be cut off, or if 

 a ligature or incision be made in its bark, the juices are 

 arrested above, and new roots are formed there ; if, on 



