CHAPTER XXIV 

 REPRODUCTION AND DEVELOPMENT OF PLANTS 



311. The Object of Reproduction. Up to this point 

 only the activities necessary to the plant itself have been 

 considered. A maple tree three feet high, or a wheat plant 

 six inches above the ground, is a complete, independent 

 plant. It responds to the influence of water and light; it 

 makes its own food; that food is digested and new cells are 

 formed from the product. Oxidation of parts of the plant 

 gives heat and energy for necessary movements. If, however, 

 the plant died at this stage, its death would be premature. 

 It would have failed to provide for the continuance of its own 

 race. The function of reproduction, without which a race 

 of plants or animals ceases, is performed only by a mature 

 organism. 



312. The Structure of Flowers. Many plants, of which 

 the bean plant is a type, reproduce by means of seeds found 

 in the pod after the flower withers. Therefore, in the study 

 of reproduction it is convenient to begin with the flower. 

 Flowers differ greatly in color, size, and shape; but if com- 

 plete, they all have petals, sepals, stamens, and one or more 

 pistils. The simplest flowers have these parts quite separate; 

 but some flowers, such as the bean, show some of these parts 

 united. 



The garden bean plant has five petals, usually white, two 

 rather closely placed petals being below the other three. On 

 the back or under side of the flower there are five green sepals, 

 partially united. The flower has also ten yellow stamens 

 and a single pistil. The knobs, called anthers, at the ends 

 of the stamens are really hollow sacs producing a large 



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