102 



SCIENTIFIC AGRICULTURE. 



and expand. The water is decomposed, its oxygen combines 

 with the carbon of the starch which has been stored up in the 

 tissues. Thus, losing a part of its carbon, the starch is con- 

 verted into sugar for the nourishment of the embryo, which now 

 begins to dilate and develop its parts. Soon the integuments 

 burst, the radicle descends, seeking the damp and dark bosom 

 of the earth, and the plumule rises with expanding leaves, to 

 the air and light. The conditions requisite for the germination 

 of the seed are, heat, moisture, oxygen, air and darkness." 



[Wood. 



Fig. A. 



[Fig, A. This cut represents a young dicotyledonous plant, with its 

 radicle, a, developed; its cotyledons, c, c, appear in the form of large 

 succulent leaves; the plumule is just appearing as a minute point 

 between the cotyledon*.] 



THE ROOT. 



The root constitutes the basis of the plant : it serves two 

 purposes in the vegetable economy, first to fix the plant 



