USES OF THE PARTS OF A FLOAYER. 141 



to understand the uses of the various parts. 

 Keeping a pumpkin vine under observation, 

 we find that pumpkins are never borne on the 

 staminate flowers, but always on the pistillate 

 flowers. Of what use then are the staminate 

 flowers ? 



2. Experiments have often been made 

 (and any one with care can repeat them), 

 which clearly show that both staminate and 

 pistillate flowers, play a part in the production 

 of seeds and fruit. A pistillate flower, tied 

 up in a thin paper bag, just before it opens, 

 and kept tied up, forms no fruit, but its ovary 

 shrivels up and withers like the rest of the 

 flower. A second pistillate flower, also tied 

 up before it has opened, but which when 

 open, has some pollen from a staminate flow- 

 er put on its stigma, forms fruit. The petals 

 of this flower wither up like the first but its 

 ovary does not, but commences to grow and 

 finally forms a ripe fruit with seeds in it. 



3. Thus we learn that for the production 

 of fruit and seeds, it is necessary for the stigma 

 of the flower to have some pollen of the same 

 kind of plant placed upon it. When this has 

 been done the flower is said to be pollinated. 

 The actual events which take place as the 

 results of pollination cannot be studied with- 



