FOR WAGGONER’S BIOLOGY 11 
1. Stage 1. Note the break in the coat. What has caused this? 
(Stage 1 should show the radicle from J to J inches in length.) 
2. Stage 2. How has the radicle changed? What new struc¬ 
tures are present? 
3. Stage 3. Explain the use of the arch of the hypocotyl. 
4. Stage 4- Describe the changes which have occurred in this 
specimen since it was planted. 
5. Stage 5. Note that sand adheres to the roots above the tips. 
(This is due to the presence of root hairs. Exercise 18.) What 
is the cause of the shrinkage of the cotyledons? 
II. Development of Corn Seedling. Arrange and make your 
drawings as in Part I of this exercise. 
1. Stage 1. What is the first structure to emerge? Examine the 
interior and note any changes. (Stage 1 should show the radicle 
one half to one inch long.) 
2. Stage 2. (In the drawing the plumule should point toward 
the top of the page.) Examine the sheath of the plumule. Open 
it and note its contents. 
3. Stage 3. Note the beginnings of the root system. Examine 
the endosperm. 
4. Stage 4- Do the parts above the ground develop as rapidly 
as the roots? 
5. Stage 5. Note the change in the endosperm. What is the 
cause of this? How will the young plant get a new supply of food? 
III. What is germination? When does the germination of a 
seed begin? 
(Note — Put peas to soak. See Exercises 12 and 16.) 
EXERCISE 12 
CONDITIONS FAVORING THE GERMINATION OF SEEDS 
Plan a number of simple experiments by means of which it may 
be determined what conditions of moisture, temperature, and air 
are favorable to the germination of seeds. The following exercises 
