142 TALKS AFIELD. 



of the plant are the same distance apart as 

 before, but those upon the stem portion 

 have separated to three times their former 

 distance. In other words, the root has 

 grown from its extremity alone, while the 

 stem has elongated between its extremities 

 and has lifted the seed-leaves into the air. 

 We have discovered a fundamental differ- 

 ence between the root and the stem. The 

 root is ever increasing by additions to its 

 young extremity, crawling by this means 

 around stones and whatever obstacles lie in 

 its way, or taking the direction of attractive 

 food supplies. The stem, on the other hand, 

 meets few obstacles to its continuous growth, 

 and each internode, or the space from joint 

 to joint, increases more or less throughout 

 its whole length. It must not be under- 

 stood, however, that there is no limit to 

 this stretching of the internode, for it very 

 soon ceases, and the upper node or joint be- 

 comes stationary. Then the younger and 

 succeeding internodes stretch until they in 

 turn become stationary ; so it happens that 

 there may be several internodes, one above 

 the other, elongating at the same time, the 

 lower and older ones perhaps slowly, the 

 upper ones rapidly. The length to which 



