REPRODUCTION IN PLANTS 



11 



of plants been taken up in a scientific manner. The achieve- 

 ments of these years have been remarkable. Much of this 

 development has been due to an increased knowledge of 

 the laws of heredity. 



REPRODUCTION IN PLANTS 1 



14. The Seed-Producing Organs of Plants. Fig. 6 

 shows the parts of a pea-blossom. The essential parts 

 are the stamens and the pistil. The 

 stamens are made up of two parts, 

 the filament and the anther. Their 

 function is to bear the pollen grains 

 which the anther contains. The pis- 

 til has three parts, ovary, style and 

 stigma. The ovary contains the ovules 

 that are to be fertilized and that will 

 then grow to be seeds. The stigma 

 receives the pollen grains. The pollen 

 grains start to grow when they come 

 in contact with the stigma. This 

 growth eventually reaches the ovules. 

 The protoplasm of the pollen unites 

 with the ovule, and a new plant is 

 formed. We recognize this new plant 

 as the embryo of a bean or kernel of 

 corn. The parent plant furnishes the food for its first 

 growth, and a supply is stored up to give the seed a start 

 in life when it separates from the mother plant. But the 

 embryo is a new plant as soon as the pollen grain unites 



l This subject is assumed to have been studied in botany. Only a brief 

 review is given here. 



FIG. 6. Section of a pea 

 blossom. S, sepal, one di- 

 vision of the calyx; K, B, 

 divisions of the corolla; 

 Sta, anthers of the sta- 

 mens; O, Sty, St, parts of 

 the pistil ; O, ovary ; Sty, 



