FLOWERS: POLLENATION AND FERTILIZATION 115 



in the structure of the seed: the ovule walls become the testa and 

 tegumen; the opening for the pollen tube is the micropyle; the 

 fertilized egg develops into the embryo, and the endosperm nuclei 

 produce the endosperm. 



The embryo may develop, to a great extent within the seed and 

 use all the endosperm, or it may develop but little and leave un- 

 used endosperm for the germination process. In either case it was 

 present at one time. 



Notice that the seed stage is only a pause in the continuous 

 circle of growth. The parent plants produce the pollen and ovules; 

 these produce sperm and egg; both grow and finally unite. The 

 embryo is formed and grows more or less within the seed, then 

 merely waits and rests till it shall have conditions favorable for 

 continuing its growth to an adult plant, again. In this way the 

 life cycle is completed. The parents die but parts of their actual 

 protoplasm live on, forever, in the new generation. 



COLLATERAL READING 



POLLENATION 



Cross and Self Fertilization in the Vegetable Kingdom, Darwin; The 

 Great World's Farm, Gaye, pp. 208-214; With the Wild Flowers, Hardinge, 

 pp. 47-55; Ten New England Blossoms, Weed, pp. 1-17, 90-98; Beauties 

 of Nature, Lubbock, pp. 117-138; The Fairy Land of Science, Buckley, 

 p. 212-237; Elementary Studies in Botany, Coulter, pp. 151-166; Plant 

 Life and Uses, Coulter, pp. 301-322; Natural History of Plants, Kerner 

 and Oliver, Vol. II, Part 1, pp. 129-283, 426-436, Part 2, 833-840, 862-866; 

 Experiments in Plants, Osterhout, pp. 286-311; Plants and their Children, 

 Dana, pp. 187-255; The Living Plant, Ganong, pp. 303-326; Practical 

 Biology, Smallwood, pp. 296-308; The Story of Plants, Allen, pp. 73-135; 

 Outline of Botany, Leavitt, pp. 120-127; Textbook of Botany, Bessey, 

 p. 421; Textbook of Botany, Strasburger, pp. 281-283; Plant Rela- 

 tions, Coulter, pp. 123-137; . Introduction to Botany, Stevens, pp. 

 166-201; Plant Structures, Coulter, p. 181; Nature and Work of 

 Plants, McDougal, pp. 149-153; Lessons in Botany, Atkinson, pp. 192- 

 193; Elementary Botany, Atkinson, pp. 351-367; Botany for Schools, 

 Atkinson, pp. 167-181; Elementary Biology, Peabody and Hunt, pp. 

 74-88; Flowers, Fruits and Leaves, Lubbock, pp. 1-44; Plant Life, Step, 

 pp. 35-58; Wonders of Plant Life, Herrick, pp. 149-173; Blossom Hosts 

 and Insect Guests, Gibson, entire; Flowers and their Friends, pp. 121-133; 

 231-239; Fertilization in the Vegetable Kingdom, Darwin, pp. 356-414, 



