14 THE WAY LIFE BEGINS 



The easter lily, like many other luminous white flowers, 

 depends largely upon night flying moths to bear its pollen. 

 White flowers are easily seen in the twilight, especially when 

 they grow close together. Night bloomers like the lily reserve 

 their fragrance and their abundant nectar flow for the night 

 hours, when the swiftly flying, long-tongued moths are about. 

 (Plate I.) 



The dusky moth, eager to reach the ring of nectar hidden 

 at the base of the pistil, drives straight into the flower. The 

 pistil, reaching far out of the cup, is sure to strike against the 

 moth as it enters. Coming, pollen-laden from a visit to a 

 nearby lily blossom, the moth rubs the pollen from its furry 

 shoulders against the sticky surface of the stigma. Pushing 

 forward into the narrow flower-cup, the moth crowds against 

 the anthers, yellow with their masses of ripe pollen. The 

 moth, having taken its toll of nectar, whirls away to another 

 lily. 



What is meant by Fertilization 



So much for the pollen bearers. In order to follow the 

 further history of the pollen after its deposit upon the stigma, 

 we shall have to turn to the microscope. The pollen grain 

 that has found its way to the stigma soon begins to absorb 

 moisture from its surface. It swells to bursting and a tube 

 extends from the pollen grain down through the loose tissue 

 of the style. The tube moves forward until it works its way 

 into the ovary and through the tissues of the ovary to the 

 ovule or egg case. Entrance is made to the ovule through a 

 small opening, the micropyle. The tip of the tube now 

 breaks and frees two or more nuclei. The first is the tube 

 nucleus which has been at the growing point of the tube in its 

 long journey. The other two are sperm nuclei, the history 

 of only one of which we are interested in following. This sperm 

 nucleus unites with the egg nucleus within the ovule. When 

 this union has been accomplished the egg is said to be fer- 

 tilized. Germination of the young plant so formed is then 

 possible. 



