Plant Study 11 



A complete flower consists of four parts calyx, corolla, stamens, 

 and pistils. Cherry, apple, and cotton blossoms are examples 

 of this class. With a complete flower before you, locate the dif- 

 ferent parts as described here. The calyx is usually green and 

 consists of leaf -like parts, the sepals, surrounding the stem 

 at the bottom of the blossom. The corolla is the spreading 

 part just above the calyx. It consists of the petals, which are 

 often white or bright-colored. Inside the corolla is a group of 

 slender parts called stamens. These are the male organs of 

 reproduction. Each stamen is made up of three parts : the long 

 slender stalk that connects with the stem is the filament (some- 

 times absent) ; the enlarged part at the top of the filament is 

 the anther ; the yellow dust of the anther is the pollen. Inside 

 the group of stamens in the middle of the flower are the pistils 

 or, in some cases, only one pistil. These are the female organs 

 of reproduction. The parts of a pistil are the ovary, which is 

 at the base of the pistil, and the style, which is the slender part 

 that supports the enlarged flattened summit called the stigma. 

 The ovary contains the ovules that when properly fertilized, 

 as described later, develop into the seeds. 



Flowers of certain species vary considerably from those of 

 the apple, cherry, and cotton. The petals may not be uniform 

 in size or may be wanting. Certain parts of the flower, in some 

 species, are lacking ; the corolla may be absent ; there may be 

 neither calyx nor corolla ; some flowers have no stamens ; some 

 have no pistils. If stamens and pistils are in different flowers, 

 termed staminate and pistillate flowers, they are known as 

 imperfect flowers. If the staminate and pistillate flowers are on 

 the same individual, the plant is said to be monoecious ; if on 

 different plants, dioecious. 



The union of the male cell and the female cell in the forma- 

 tion of the embryo of a seed is known as fertilization. This is 

 accomplished after the pollen is carried to the stigma. During 

 a certain period of growth, the surface of the stigma is moist 

 and, if a fertile pollen grain adheres to the stigma at this time, 



