104 CIRCULATION AND USES OF FOOD BY PLANTS 



a season ; others, such as the big trees of California, live for hun- 

 dreds of years. Some insects exist as adults but a day, while the 

 elephant is said to live almost two hundred years. The span of 

 life from the time the plant or animal begins to grow until it dies 

 is known as the life cycle. 



Reference Books 



elementary 



Hunter, Laboratory Probleyns in Civic Biology. American Book Company. 

 Andrews, A Practical Course in Botany, pages 112-127. American Book Company. 

 Atkinson, First Studies of Plant Life, Chaps. IV, V, VI, VIII, XXI. Ginn. 

 Coulter, Plant Life and Plant Uses, Chap. V. American Book Company. 

 Dana, Plants and their Children, pages 99-129. American Book Company, 

 Mayne and Hatch, High School Agriculture. American Book Company. 

 Hodge, Nature Study and Life, Chaps. IX, X, XI. Ginn and Company. 

 MacDougal, The Nature and Work of Plants. The Macmillan Company. 



ADVANCED 



Apgar, Trees of the United States, Chaps. II, V, VI. American Book Company. 

 Coulter, Barnes, and Cowles, A Textbook of Botany, Vol. I. American Book 



Company. 

 Duggar, Plant Physiology. The Macmillan Company. 

 Ganong, The Teaching Botanist. The Macmillan Company. 

 Goebel, Organography of Plants, Part V. Clarendon Press. 

 Goodale, Physiological Botany. American Book Company. 

 Gray, Structural Botany, Chap. V. American Book Company, t 

 Kerner-Oliver, Natural History of Plants. Henry Holt and Company. 

 Strasburger, Noll, Schenck, and Karston, A Textbook of Botany. The Macmillan 



Company. 

 Ward, The Oak. D. Appleton and Company. 

 Yearbook, U. S. Department of Agriculture, 1894, 1895. 1898-1910. 



