43 



and will therefore enable you to form more accurate judg- 

 ment as to the reliability of the evidence. However, before 

 attempting to present this data I wish first to discuss briefly 

 the morphology and physiology of the flowers of our fruit 

 trees. 



The term fruit as it is ordinarily used means the pulpy 

 m.ass connected with and surrounding the seeds of our 

 various orchard plants. It develops primarially as a pro- 

 tection to the growing seeds which are the vital products of 

 the plants. 



Seeds are the result of the union of two unlike cells 

 known by various names, but for our discussion we may call 

 egg cell and sperm cell. These cells are produced in differ- 

 ent organs in the flowers, sometimes in different flowers, more 

 commonly in the same flower. Our common tree fruits such 

 as apple, pear, peach and plum produce complete, perfect 

 fl.owers. Perfect because they contain the essential organs 

 of reproduction ; complete because they contain all the floral 

 parts, pistil, stamens, petals, sepal. 



The essential organs of the flower are the stamens which 

 bear the pollen grains or sperm cells, and the pistil made up 

 of ovary, style and stigma which bear the ovules or egg 

 cells. These are soft single cells found in the ovary which 

 is the tube like portion forming the base of the pistil. 



When the ovules are ready to be fertilized the stigma 

 prepares itself for the reception of the pollen. Usually this 

 is effected by a gellatinous exudation making the surface 

 stick}^ and forming a medium in which the pollen is readily 

 caught. This deposition of pollen on the stigma is known 

 as pollination. When the pollen grain on the stigma pro- 

 duces its pollen tube, which is an outpushing of the coat of 

 the cell and this tube penetrates the stigma, passes through 

 the style, enters the ovary, attaches itself to the egg cell and 

 when the nuclus of the sperm cell or pollen grain has passed 

 through this tube and has become fused with the nucleus of 

 the egg cell then fecundation or fertilization has been 

 brought about. This stimulus is necessary to start the 

 growth of the flower parts which ultimately develop into 

 the seed and fruit. 



If these uniting cells, the egg and the sperm are borne 

 by the same plant, or in the case of our orchard tree fruits 



