FERTILIZATION OF FLOWERS. 



[Read before tlie Albany Institute, April 15, 1884.] 



The fertilization or pollenization of flowers is the application of 

 proper pollen at the proper time to the stigma of the pistil and the 

 consequent transfer of the pollen contents to the ovules. The process 

 is twofold. First, the pollen -rains must be transferred from the 

 anthers, Avhere they are produced, to the stigma; second, the pollen 

 contents must be conveyed from the stigma to the ovules. The first 

 is a mechanical operation and is chiefly effected by agencies external 

 to the plant, the second is a kiud of vegetative or natural process, and 

 is carried on by the plant itself. By proper pollen wc mean that 

 which is capable of germination. It implies that the pollen must be 

 mature and well developed, and generally that it must belong to the 

 same species of plant as the stigma to which it is applied. The 

 proper time for the application is while the stigma is in a receptive 

 condition. If the pollen is applied before the stigma is mature, or 

 after it has become dry and withered, no fertilization will result. 

 The floral organs immediately and necessarily concerned in fertiliza- 

 tion are the stamens and the pistils. They are indispensable and are 

 therefore called the essential organs of the flower. The other parts of 

 the flower, the calyx and corolla, are merely accessory or aiding and 

 protecting organs, and may not always be present. 



The office of the stamens is to produce the pollen. This is regarded 

 as the male element, and flowers which bear stamens but no pistils are 

 called male flowers or staminate flowers. They are always sterile, that 

 is, they never produce seeds. 



The office of the pistil is to produce the small cells or incipient seeds 

 called ovules. These are developed in the swollen base or ovary of the 

 pistil and are regarded as female cells. Hence those flowers which 

 bear pistils but no stamens are called female flowers or pistillate or 

 fertile flowers. Many flowers have both stamens and pistils, and are 

 therefore considered bisexual or hermaphrodite. They are called per- 

 fect flowers. Flowers with but one kind of the essential organs are 

 called imperfect. If both kinds of imperfect flowers occur on the 

 same plant, the inflorescence is said to be monoecious. If the two 



