HOME AND SCHOOL EXERCISES 83 



and forms a growth or elongation which reaches through the 

 entire length of the silk. This is necessary in every case before 

 the kernels can be formed on the cob. Samples of ears show- 

 ing places where kernels were undeveloped should be brought 

 to school and examined by pupils. 



23. Hand Pollinating. — When plants aie in blossom in the 

 window or garden, select some containing both stamens and pistils. 

 Just before they open, take a pair of scissors, or fine-pointed knife, 

 and remove the stamens from a number of flowers, being careful not 

 to injure the pistil or other parts. Cover these flowers with small 

 paper bags or folded papers tied with a string or fastened with a, 

 rubber baud about the stems. This is to prevent the air or insects 

 from carrying pollen to these flowers. After a few days, when the 

 pistils have developed, apply pollen from other flowers of the same 

 kind by hand. This may be done by using a small soft feather or 

 brush. Rub the feather on the stamens of flowers where you wish 

 to collect pollen, and then rub it on the pistil of the flowers from 

 which the stamens were removed. The bag is again placed over 

 these flowers until the fruit or seed begins to grow. Then the bags 

 may be removed. The time required will probably not be more than 

 two weeks. 



The methods described here are similar to those used by 

 experimenters in plant breeding. The stamens of flowers are 

 removed to prevent self-pollinating, and the pollen of desired 

 kinds which they wish to cross upon those plants is brought 

 by the hand method and placed on the pistils. Seed from such 

 crosses may produce new and more valuable varieties. Among 

 hundreds or thousands of trials, possibly only one or two 

 improved varieties may be found. 



