INTRODUCTORY 265 



now simply because it explains flowers more completely 

 than any other single thing explains them. 



B. Protection. There are certain parts of the flower, 

 parts that are usually green, which are .concerned with 

 protection more than they are with pollination. They 

 are the outermost parts of the flower and they protect 

 the inner parts. These outermost parts are the sepals. 

 They form the covering of the flower buds, and, in flowers 

 which are open, they may be found beneath the petals. 

 Sepals usually look like little leaves. You have already 

 noted the injury which may come to the tender inner 

 parts of fruit blossoms when a frost comes after the sepals 

 have opened (Section 51). 



C. Evolution of Flowers. You cannot understand much 

 about flowers without understanding at least a little about 

 evolution. Pollination helps us to understand the ad- 

 vantages of the many different kinds of flowers and evolu- 

 tion helps us to understand why there are so many dif- 

 ferent kinds. 



Evolution is the name of an idea which is very big, but 

 not very complex. It is an idea which is neither too big 

 nor too complex for you to grasp, and it will help you under- 

 stand living things as no other idea can. It helped the 

 scientists of the past as no other idea ever did, and the 

 scientists of the present accept it as a great fundamental 

 truth. All things keep changing more or less. The sum of 

 such changes makes up what we call evolution. 



We may say of flowers that they have been evolved in 

 connection with reproduction. By this we mean that all 

 plants have come from simple forms without flowers which 



