LESSOX 2.] GROWTH OF THE PLANT FROM THE SEED. 



18. So the youngest seedling, and even the embryo in the seed, 

 is already an epitome of the herb or tree. It has a stem, from the 

 lower end of which it strikes root : and it 



has leaves. The tree itself in its whole 

 vegetation has nothing more in kind. 

 To become a tree, the plantlet has only 

 to repeat itself upwardly by producing 

 more similar parts, that is, new por- 

 tions of stem, with new and larger leaves, 

 in succession, while beneath, it pushes 

 its root deeper and deeper into the soil. 



19. The Opposite Growth of Root and 



Stem began at the beginning of germi- 

 nation, and it continues through the 

 whole life of the plant. While yet 

 buried in the soil, and perhaps in total 

 darkness, as soon as it begins to grow, 

 the stem end of the embryo points 

 towards the light, curving or turning 

 quite round if it happens to lie in 

 some other direction, and stretches 

 upwards into the free air and sunshine ; 

 while the root end as uniformly avoids 

 the light, bends in the opposite direction 

 to do so if necessary, and ever seeks to bury itself more and more 

 in the earth's bosom. How the plantlet makes these movements we 

 cannot explain. But the object of this instinct is obvious. It 

 places the plant from the first in the proper position, with its roots 

 in the moist soil, from which they are to absorb nouri.-hment, and iu 

 leaves in the light and air, where alone they can fulfil their office of 

 digesting what the roots absorb. 



20. So the seedling plantlet finds itself provided with all the 

 organs of vegetation that even the oldest plant Assesses, namely, 

 root, stem, an 1 leaves ; and has these placed in the situation where 

 each is to act, the root in the soil, the foliage in the light and air. 

 Thus established, the plantlet has only to set about its proper work. 



21. The different Mode of Growti. of Root and Stem may also be here 



mentioned. Each grows, not only in a different direction, but in a 

 different way. The stem grows by producing a set of joints, each from 



FIG. 7. Germinating Red Maple., further developed. 



