Seeds and How They Grow 



507 



the top, where the corn "silk" was once attached. The hilum 

 and the micropyle, although present as in the bean, are covered 

 and so cannot be seen. Cutting off a thin longitudinal section 

 from the face of a well-soaked grain at right angles to its flat 

 broad sides, observe in the part remaining the cotyledon as well 

 as the hypocotyl and the epicotyl ; also observe the endosperm that 

 surrounds the embryo. 



Taking another well-soaked grain, make a longitudinal section 

 directly through the middle of the broad part of the grain at right 

 angles to its narrow sides, and again identify the cotyledon, the 



GROWTH OF THE CORN SEEDLING 



hypocotyl, the epicotyl and the endosperm. By soaking the cut 

 sections in a solution of iodine, the various parts may more easily 

 be recognized. Iodine colors the starch dark blue or black and 

 stains the embryo yellow or orange. 



In the process of germination, the hypocotyl, protected by a 

 cap, pushes down into the soil and the root develops. The plumule 

 meanwhile pushes its pointed end up through the soil and soon 

 unrolls its small leaves. The seedling thus becomes able to make 

 its own food. 



