rNBLUENCE OF POLUBN. 117 



CHAPTEE IX. 



INFLUENCE OF POLLEN. 



Whether the influence of the pollen extends heyond 

 the OTule and ovary or not, is a question that has not 

 attracted any considerable attention from either regetable 

 physiologists or practical cultivators of plants. It is 

 quite evident, however, that there is a reciprocal action 

 extending far beyond the ovary, else unfertilized ovules 

 would not so uniformly show the non-development of the 

 ovary as well as various external organs. In the Eose 

 family, in which we find the Apple, Pear, Quince, etc., 

 the embryo fruit is formed before the flowers expand, 

 and it is the same in the Melon family, and, in fact, in a 

 large majority of plants the seed-vessels and ovules are 

 plainly discernible long before the flowers appear or 

 the sexnal organs are developed ; but if the ovnles are 

 not fertilized, the entire flower and flower-stalk soon 

 wither and drop off. When fertilization occurs, an 

 immediate change in the parts take place ; the ovary and 

 its envelope, whether in the form of a pulpy fruit or 

 membranous pod or shell, respond to the demand of the 

 fertilized ovule, enlarging and thickening as it becomes 

 the natural receptacle of the embryo seeds. The flower- 

 stalk supporting these organs also enlarges, as it becomes 

 the vehicle through which nutriment passes from the 

 parent stock to the flower and fruit. The calyx of the 

 flower and other leaf-like organs assimilate the crude sap 

 which reaches them, thereby aiding in the development 

 of the embryo seeds and the seed-vessel. In the absence 

 of fertilization, all the various parts of the flower, embryo 

 fruit and fruit-stalks soon wither away. This is the 

 general result of non-fertilization of the embryo, as every 

 cultivator of plants must have seen. But while it is 

 generally conceded that the presence of the fertilized 



