CHAPTER V 



THE FLOWER 



Having studied the three primary parts of the pUant, the 

 root, stem and leaves, we now turn our attention to the most 

 important secondary organ, the flower. The flowers of many 

 plants are objects of beauty, but the great majority of plants 

 bear flowers which are very small and inconspicuous, or which 

 are of such character that they do not attract the attention of 

 the casual observer. Many people are so accustomed to think- 

 ing of flowers as mere objects of beauty that they fail to realize 

 the very great importance of these organs in the life history of 

 the plant. The flowers contain the sexual organs of the plant 

 and are necessary for the production of seeds and fruits. 



Parts of the Flower. — The flower does not present any new 

 structures, but is a shortened stem bearing circles of leaves, 

 which have been greatly modified in shape and color into 

 parts constituting the flower. Instead of being borne on a 

 long stem, they are now brought together in circles and the 

 shortened stem is known as the receptacle, or torus; the first or 

 outer circle, composed of parts which are usually green and 

 resembling ordinary leaves, is known as the calyx, and each 

 leaf-like part is called a sepal; tlio second circle or series of 

 circles composed of parts which also have some resemblance 

 to leaves but which are usually colored is known as the corolla, 

 and each part is called a petal; the third set of organs consisting 

 of one or more circles is composed of stamens which bear very 

 little resemblance to leaves; the last or central group consist- 

 ing of one or more organs which may be distinct or united is the 

 pistil which also bears very little resemblance to leaves. (Figs. 

 54 



