BOTANY FOR BEGlNNERS-ll. 



THE ESSENTIAL ORGANS. 



The essential organs of the flower — the stamens and 

 pistils— are the vef^^ ones that to the casual observer may 

 seem least essential. From the standpoint of beauty, at 

 least, the sepals and petals are of most importance ; but 

 use and not beauty is the plant's first requitement and all 

 the delicate hues and varied modifications of petal and se- 

 pal are but so many aids to those insignificant looking 

 organs in the centre of the flower. The contents of stamen 

 and pistil must be joined ot no ffuitwill beset^ and in con- 

 sequence the flower will fail to accomplish the very object 

 fo^" which it was produced. 



THE PiSTlE. 



The pistils always occupy the centfe of the flower, ex- 

 cepting in the case of a few staminate blossoms when no 

 pistils are present-. A typical pistil such as 

 that of the cherry (fig-. 5^ a.) is a bottle- 

 shaped organ with three well defined re- 

 gions. The enlarged loxver part^ contain^ 

 ing the embryo seeds, is the ovarv^ The 

 slender portion above is the style and the 

 Small knob at the top the stigma. Of these 

 three parts, the style is of least importance 

 and it is not found in the flowers of many 

 Species, the stigma in such cases growing 

 from the top of the ovary, as in thetrillium 

 (fig. 4).. 



The stigma is the part of the flower that receives the 

 pollen grains from the vstamens. In the process of fertili- 

 sation the pollen falling On the stigma germinates there^ 

 ^ach grain pf oducing a tiny tube which makes its way 

 downward thfough the loose tissues of the style to the 

 ovary and there stimulates the embryo seeds into 

 growth. If no pollen falls on the stigma, no seed will be 

 formed in the ovary. The stigma is therefore usually 

 moist and sticky so that the pollen will adhere to it and 



Fig. 5. 



