INTRODUCTION 19 



flower. For those who have not had the benefit 

 of such instruction the following brief discussion 

 should be helpful. It will be all the better if the 

 readers, in studying it, have at hand a few butter- 

 cup blossoms, so that they can see for themselves 

 just what is meant. 



THE PARTS OF THE FLOWER 



The Buttercup is an excellent blossom to illus- 

 trate the structure of a simple flower. If we have 

 in hand a newly opened Buttercup blossom we 

 \vill readily find five greenish sepals at the base 

 of the flower, which serve to cover it in the bud. 

 When these sepals are to be considered as a whole 

 w r e call them the calyx. In many flowers they 

 appear to be united, forming what is called the 

 calyx-tube. Such a calyx generally has pro- 

 jections along the outer margin which are called 

 calyx-lobes and which usually represent the 

 individual sepals. 



Just above the calyx in the blossom of the But- 

 tercup are five yellow petals. These form the chief 

 part of the flower so far as conspicuousness is 

 concerned and their special function is to attract 

 insects to the blossom. If one of them is removed 

 there will be found at its base a tiny nectar pocket 

 in which nectar is secreted for the visiting bee. 

 As the sepals when taken together are called the 

 calyx, so the petals when taken together are called 



