424 PLANTS AND THEIR RELATION TO MAN 



fruits in the spring, the chestnut trees ripen their fruits in the 

 autumn. Flowers and fruits are intimately connected because 

 the fruit is the outgrowth of the flower. The plant which fails 

 to produce flowers fails also to produce fruit ; the plant which 

 produces poor flowers produces also poor fruit. Some flowers 



develop into luscious, juicy fruits, 

 like apples, pears, peaches ; others 

 into hard fruits, like grains of 

 wheat and nuts of the pecan 

 tree. Some flowers develop into 

 inedible fruits, like the acorns of 

 the oak tree and the papery keys 

 of the maple tree. 



The structure of a flower. 

 When we examine a flower such 

 as a buttercup, we find on the 

 outside of it a circle of small green 

 leaves. The circle of leaves is 

 called the calyx and the separate 

 leaves are called sepals. The 

 sepals are of great service to the 

 young unopened flower, because 

 they protect it from cold, rain, 



FIG. 289. A flower cut lengthwise to anc [ w i n d, and from insect enemies, 

 show calyx, corolla, stamens, and pistil. . . 



Next to the calyx is a circle or 



colored leaves, called the corolla, the separate leaves of which 

 are called petals (Fig. 289). 



Next to the petals are the stamens, threadlike bodies with 

 knobs on their ends. The slender stalk of the stamen is called 

 the filament, and the enlarged end is called the anther. The 

 anther is really a box or sac which contains minute powdery 

 grains called pollen. Before the flower is in full blossom the 

 anther sac is closed and the pollen grains are protected. When 



