6 BULLETIN 521, U. S. DEPARTMENT OF AGRICULTURE. 
Lesson 5.— Flowers. 
1. Function of flowers. 
2. Parts of flowers. 
3. Forms of flowers. 
Illustrative material: Flowers of different forms; charts showing struc- 
ture. 
Lesson 6. — Fertilization of the Ovule. 
1. Conditions essential to fertilization. 
2. How the pollen reaches the ovule. 
3. Devices for securing cross-pollination. 
Illustrative material: Charts showing fertilization of the ovule. 
Lesson 7. — Some Principles of Plant Breeding. 
1. Law of heredity. 
2. Law of variation. 
3. Selection. 
(a) Natural. 
(&) Selection by man. 
4. Inducing variation. 
5. Technique of cross-pollination. 
6. Propagation. 
(a) Sexual. 
(&) Asexual. 
Illustrative material : Chart showing Mendel's law. 
Exercise 3. — A Study of Plant Grovith. 
Purpose : To show how plants develop from the seed. 
Directions : Have each student fill' a flat box to a depth of 5 inches 
with sand. On one side seeds of corn, squash, peas, and beans 
should be planted at a depth of 1 inch, and on the other side the same 
kind of seeds 4 inches deep. The planting should be done two weeks 
before the study is to be made, and the box placed where it may be 
kept warm and moist. The seeds should be studied by the students 
as they germinate and as the plants develop. 
Record and report: Drawings of an entire plant of each kind 
should be made and the parts named. In a written report which 
should accompany the drawings the following questions should be 
answered: In what respects are the pea, bean, and squash alike? 
How do they differ from the corn and wheat in germination? In 
relation to its cotyledons, how does the pea differ from the bean in 
germination? How do the cotyledons of the bean differ from those 
of the squash in the development of the plant? How 7 does the squash 
get rid of its seed case? What service do the cotyledons render the 
developing plant? What happens if one or both of the cotyledons 
are broken off? Why may corn and peas be planted deeper than 
beans and squashes? How do the roots of the plants differ? 
Lesson 8. — Elements of Plant Food. 
1. Sources of plants. 
2. Definition of element and compound. 
3. Food from the air. 
4. Food from the soil and water. 
