92 LABORATORY MANUAL 



hilum, locate a small opening, the micropyle. Draw 

 the bean from the side, and from the edge. Label the 

 parts. 



(b) Internal structure. With the scalpel carefully 

 open the seed by cutting through the testa along the 

 convex side. Again examine the testa. Within, the 

 testa notice the embryo plant consisting of : 



(1) the cotyledons, two large seed leaves. Are these 

 joined? Where? 



(2) the plumule, the small rudimentary leaves be- 

 tween the cotyledons ; 



(3) the hypocotyl, the rudimentary stem and root. 

 Draw one of the cotyledons showing the plumule 



and the hypocotyl in position, labeling parts. 



B. Corn. 



In the bean, the entire contents of the seed consist 

 of the embryo ; but this is not always the case. Often, 

 as in corn, food is stored in a part called the endosperm. 



(a) External structure. Examine a kernel of corn. 

 Note the outer covering ; also notice the groove where 

 the embryo lies. The hilum and micropyle are at the 

 small end of the kernel. Draw the flat side of the 

 kernel showing the position of the embryo. 



(b) Internal structure. Remove the skin. Cut the 

 kernel lengthwise, perpendicular to the flat surface. 

 Most of the outside of the kernel consists of a white 

 flowery substance, the endosperm. Of what use is this? 

 Find the embryo. Locate the plumule, radicle, or root, 

 and the cotyledon. Compare each of these parts with 



