FOR WAGGONER’S BIOLOGY 
9 
by the number of times that this quantity is contained in the total 
quantity.) What does the number of seeds borne by a single plant 
indicate with regard to the necessity of seed dispersal? 
(Note — Put corn and bean seeds.to soak 24 hours preceding 
their use in Exercise 10. Make a collection of algae for Exercise 34.) 
EXERCISE 10 
THE SEEDS OF THE CORN AND BEAN 
Provide a sufficient supply of corn kernels and bean seeds so 
that each pupil may have at least two specimens of each. Soak 
half of the supply of each for one or two days previous to using. 
I. Structure of the Bean Seed. 
1. The Dry Seed. Note the size, the shape, and the color. Make 
a comparison of the length, the breadth, and the thickness of the 
seed. What is the nature of its covering? Note the position of the 
scar or hilum. What is its cause? Note the hole at the end of 
the hilum, the micropyle. What is the function of the micropyle? 
2. The Soaked Seed. Compare with the dry bean in size, in 
smoothness, and in the texture of its covering. Remove the coat. 
From what part of the ovule did it develop? Note the structure 
just within the micropyle. This is the hypocotyl. Its extreme tip 
is the radicle. The two halves are the cotyledons. Examine the 
cotyledons. Were both attached to the hypocotyl? Examine the 
one which you find attached. Note the tiny structure which lies 
between the cotyledons at the end of the hypocotyl. This is the 
plumule. (Use a lens.) Into what does the plumule develop? 
Note the relation of its parts to one another. 
3. The entire structure within the coats of the bean constitutes 
the embryo, or young plant. Make a drawing of the bean as it 
appears when opened. Show all its parts. 
II. Structure of Corn Kernel. 
1. Dry Kernel. Note the shape, the color, and the markings. 
Compare the ends of the kernel. What is the cause of the dent ”? 
Note the oval area on one side. 
