212 NATURE STUDY AND AGRICULTURE 



The children cannot see what takes place after the 

 pollen grain has fallen upon the stigma. But they should 

 know that the pollen grain germinates or sprouts on the 

 stigma and a small tube grows down the style into the 

 ovary. In this tube are certain small cells. One of these 

 cells unites with a cell in one of the ovules, and the new 

 cell formed by this union is the beginning of a new plant. 

 It forms the embryo, which is the essential part of the seed. 

 This act, the uniting of these two cells, is called fertiliza- 

 tion. Pollination, then, is the first act, and fertilization 

 the second in forming the seed. The children now see 

 why pollination is necessary for a plant to produce seed. 



Problem. — Would it be possible for you to pollinate a 

 flower by hand, choosing the plant from which the pollen 

 is taken? 



Remove the stamens of a nasturtium in flowers as in 

 the previous experiment, then with a brush or triangular 

 bit of paper transfer some pollen to the stigma. Place a 

 bag over it so no other pollen can get on it. This is known 

 as hand pollination. 



Cornflower. Find, if possible, some belated corn plants 

 that are still young enough to show fresh tassels and silks. 



How many kinds of flowers do' you find on the corn? 

 The most prominent kind forms the tassel. Examine a 

 tassel. Is it a single flower or a cluster of many? Have 

 these flowers bright petals as the nasturtium? What 

 essential part of the flower is found in the tassel? Since 

 only stamens are found here this is called a staminate 

 flower. Can you find any pollen in the stamens ? What is 

 the other essential organ of any flower ? When the pistils 

 are borne in separate flowers we call these pistillate flowers. 



