HYBRIDIZING PLANTS. 



It is necessary to remember that in the great majority 

 of flowers the pollen, whether deposited by wind, insect 

 or any other agency, or whether it is extraneous pollen 

 introduced by the h^^bridizer, begins to germinate on the 

 surface of the stigma and produces a pollen-tube. This is 

 the commencement of the actual process of fertilization or 

 impregnation. Of course it is of the utmost importance 

 that extraneous pollen applied in the art of artificial 

 crossing should be in the proper condition, neither too old 

 nor too 3'-oung. The operator with his instrument re- 

 moves the pollen from the stamens of the flowers selected, 

 and applies it to the stigmatic surface of the flow^er oper. 

 ated upon — in other words, the breeder undertakes to a 

 limited extent the duties of Nature. He prevents self-fer- 

 tilization by removing the anthers at an earl3^ stage in the 

 growth of the flower selected for manipulation, and with 

 the guidance of knowledge and experience selects the 

 extraneous pollen which he intends to introduce with a 

 regard to whatever dominating influences or qualities it 

 carries with it, thus stamping the future seed with its 

 potency. The pollen tube grows in length with greater 

 or less rapidity in different species of plants, and in the 

 process forces its way through the conducting tissues in 

 the interior of the st3de untilit reaches the ovarian cavity. 

 It might be in the ovary that one or more ovules are 

 found, and one can always distinguish in them certain 

 parts, viz: a central mass of cellular tissue, known as the 

 nucellus, enclosed in either one or tw^o coats, called by 

 botanists the integuments, and the w^hole is attached to 

 the placenta by a short stalk. The integuments, however, 

 are not entire, as there is a minute aperture at the anterior 

 end, termed the micropyle, through which the pollen-tube 

 could enter in order to realch the embryo-sac, so that the 

 contents of the former might be brought in contact with 

 the contents of the latter, becomes evident. The result of 

 impregnation is that inside the embrj^o-sac, an embrj^o 

 begins to form, and at the same time the fertilized ovule 



