234 



A YEAR IN SCIENCE 



ous part of a flower because of its bright color. The 

 corolla is made up of leaf -like parts called petals. 3, Just 

 within the" corolla are a number of slender structures, 

 the stamens. Each stamen has a slender stalk, the 

 filament, the end of which is enlarged to form the 

 anther. Within the anther is a powder-like substance 

 called pollen. 4. In the center of the flower is the 

 pistil. The swollen base of the pistil is the ovary. 

 Above this is a slender stalk, the style, at the top of 



Pistil 



Fig. 100. Section of a flower of a hyacinth. 



which is an expanded, often branched structure, the 

 stigma. In the ovary are the ovules which under cer- 

 tain conditions develop into seeds. 



Formation of seeds. Only two parts of a flower, the 

 ovule and pollen, are necessary to form a seed. If 

 we examine a very thin section of an ovule under a 



