REPRODUCTION IN PLANTS 71 



A. Floral envelopes. Most flowers have parts shaped more 



or less ijike leaves which have either green or 

 bright colors. These parts are arranged in one 

 or more circles and make up the floral envelopes. 



1. How many parts are there in the floral envelopes of a 



tulip? State the color or colors of these parts 

 in the flower you are studying. 



2. When there are two circles to the floral envelopes, an 



outer composed of green parts and an inner made 

 up of brightly colored parts (as in the trillium or 

 the apple blossom), distinct names are given to 

 the various parts. The outer circle is called the 

 calyx and its parts are known as sepals; the 

 inner circle is called the corolla and each of its 

 parts is called a petal. 



a. State the number and color of the sepals in the 



calyx of the trillium. 



b. How many petals do you find in the corolla? 



Describe their color. 



3. Draw a side view of a tulip before it has fully opened. 



Label flower-stalk and floral envelopes. 



B. Essential organs. In the central part of the flower are 



the organs without which the work of the flower 

 cannot be performed. For this reason they are 

 called the essential organs. 



1. The organs arranged in a circle just within the floral 



envelopes are known as stamens. State the 

 situation and the number of stamens in the tulip. 

 What is the number of stamens in the trillium or 

 apple blossom ? 



2. Each stamen consists of a stalk called the filament 



and an enlarged part known as the anther. 

 Name and describe each of the parts of a stamen. 



3. Make a drawing twice its natural size of one of the 



stamens. Label filament, anther. 



4. Find a flower the stamens of which have a powdery 



substance known as pollen. Which part of the 

 stamen produces the pollen ? 



5. The organ at the center of the flower is called the 



pistil. It consists of three divisions at the top 



