PHYSIOLOGICAL PROCESSES IN PLANTS 71 



2. What advantage are these sports to breeders ? 



Note. Professor De Vries has shown, by cultivating American eve- 

 ning primroses in Europe, that such sudden changes in environment may 

 cause not only varieties but new species to be formed. It is supposed 

 that all varieties of dogs thus originated from the wild dog, all varieties 

 of apples from a wild crab apple, and all varieties of pigeons from a wild 

 pigeon, etc. 



Questions 



1. What is a seedling ? 



2. Why are the cotyledons often called " seed leaves " ? 



3. What is the main use of the cotyledons of the bean ? 



4. What is the use of the endosperm of corn ? 



5. Give some of the methods used in plant breeding. 



6. What are hybrids ? How are they commonly formed ? 



7. Who is Burbank, and what has he done ? 



8. What is meant by the term heredity ? 



9. Explain the statement by Cornwall, " Nature ever yields 

 reward to him who seeks and loves the best." 



10. Why is plant and animal breeding of the highest 

 importance to a nation ? 



11. What is meant by the term hereditary percentage ? 



12. How compute the percentage of germination of seeds ? 



Special Reports 



1. Corn, and its use in making alcohol. 



2. Barley and beer making. 



3. Burbank and his work. 



4. Some new plant creations. 

 6. Plant breeding. 



6. Any newspaper or magazine articles pertinent to your studies. 



7. The United States Government plant-breeding laboratory. 



8. Corn culture and breeding. 



References 



Hunter, Essentials of Biology. Chap. VI. 

 Goff and Mayne, First Principles of Agriculture. 



Hartley, " Injurious Effects of Premature Pollination." Bulletin 22, 

 Plant Industry, U. S. Department of Agriculture, 1902. 



