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 
will 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 
we 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 
