188 FLOWERS 



166. POLLINATION 



Object. To find out whether pollen is necessary to the 

 production of seeds. 



Apparatus. Any blooming plants having large flowers or 

 flowers whose stamens 'may easily be seen, a pair of sharp-pointed 

 scissors, and paper bags. 



Method. Carefully remove the stamens from some 

 flowers which are just opening, clipping off the anthers. 

 Then cover the flowers with a paper bag, tying it so that no 

 pollen can get in from any other flower and reach the stig- 

 mas. Treat other flowers in the same way, but do not cover 

 them with a bag. Thus the first flowers can receive no 

 pollen, while those of the second sort are open to the visits 

 of insects and winds. After ten days remove the bag and 

 compare the two flowers. 



Conclusion. What must be inferred as to the necessity 

 for pollen in the production of seeds ? 



Note. Experiments in pollination are seldom successful when 

 undertaken within the house. This is due to absence of insects and 

 to shelter from the winds. If experiments must be made in the 

 laboratory, pollination must be done by hand, and care must be 

 observed to get pollen which is just ripe and to place it on a stigma 

 which is ready to receive it. 



All such experiments succeed much better when made in a garden 

 where winds and insects have free play. 



167. POLLINATION 

 Object. To illustrate pollination by insects. 



Apparatus Flowers of toadflax, four-o'clock, iris, cypripedium, 

 or honeysuckle. The experiment is best made in the field where 

 the plant is growing. 



