THE WAY LIFE BEGINS 13 



number of the sepals and petals; the stamens and pistil may 

 also be greatly increased in number. The 'flower', as we 

 commonly use the word, includes the four types of structure 

 seen in Figure I, the stamens and the pistil being, however, 

 the essential organs for producing the new generation. 



The Easter Lily 



Let us now examine the flower-cup of the lily somewhat 

 more closely. (Plate I, frontispiece.) In looking into the lily 

 cup, the bright yellow anthers at once attract our attention. 

 The six anthers, we note, are supported on their long slender 

 filaments. Each anther produces and stores pollen in large 

 quantities. When the anther sac is full of pollen, it bursts 

 and discharges its contents. The nature of the pollen grains or 

 sperm cells and what becomes of them will be discussed later. 



Turning next to the pistil, we find it enlarged at the bottom 

 of the flower-cup in such a manner as to form the three- 

 chambered, elongated ovary. Within these chambers are 

 found many bodies called ovules, arranged along their inner 

 walls. Each ovule is attached to the side of the chamber of 

 the ovary by a tiny stem through w T hich it receives its nour- 

 ishment. Within the ovule is found the egg of the plant, the 

 ovule acting as a protecting envelop. From the top of the 

 ovary rises a slender tube, the style, and at the upper end of 

 the style, lifted far out of the lily vase and above the stamens, 

 is the three-lobed stigma. The stigma is greenish in color, 

 and its surface is covered with a sticky secretion. 



The Sphinx Moth and the Easter Lily 



We have seen that the pollen, when ripe, is shed by the 

 anthers, and that the eggs of the ovary are in the same flower- 

 cup. Since it is necessary that a sperm cell reach the egg in 

 order that a new plant may be produced, it would seem a 

 simple matter, in the case of the lily, for the sperm to find 

 their way to the eggs of the same flower. Such an event is 

 amply provided against by the greater length of the style and 

 by insect visitors, the sphinx moths, which carry the pollen 

 of one plant to the stigma of another. 



