the mother plant has stored up the proper nourish- 

 ing matter, or prepared food, of which the root is to 

 be made up, and the plantlet is to be nourished un- 

 til it is able to provide for itself. 



When the seed is placed in the soil provided with 

 the proper warmth and moisture, it soon begins its 

 growth, the root is formed from the surrounding 

 nourishment, the stem or radicle is lengthened, and 

 the plumule enveloped in the cotyledons, are pushed 

 up to the light and air. The cotyledons open out 

 and the plumule grows up on a stem and opens out 

 a second pair of leaves, and continues to grow up- 

 ward in joints each from the summit of the one 

 below. 



The opposite growth of root and stem began at 

 the beginning of germination, 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 em- 

 bryo points toward the light curving or turning 

 quite around, if it happens to lie in some other direc- 

 tion and stretches upward 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. 



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 nourishment, and its leaves in the light 

 air, where alone they can fulfil their office of digest- 

 ing what the roots absorb. 



The different mode of growth 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, 



188 



