POLLINATION AND FERTILIZATION 171 



portant to remember that pollen should not be collected from 

 flowers which have already opened, because bees working on 

 the blossoms will have brought pollen from other flowers and 

 it will be mixed; therefore, in selecting blossoms from which 

 pollen is to be obtained, it is necessary to choose flowers not 

 yet opened. It is best to select buds which are full-grown 

 and almost ready to open, but whose petals as yet are closed 

 so that bees have not entered. These buds can be picked 

 and placed in paper bags. 



One method of obtaining pollen from the blossoms is to pull 

 off the corolla and place the flowers on newspapers in the sun- 

 light until the anthers dehisce and shed the pollen. A much 

 neater way is to scrape or cut the anthers out of the bud; 

 in this way they can be obtained nearly free from other ma- 

 terial. The anthers are placed in a watch glass and dried 

 in the sun until the pollen is shed. It is best to put the watch 

 glass on clean sand in a shallow box, which should be covered 

 with a pane of glass to prevent the entrance of insects and 

 dirt. When a large number of samples of pollen are to be 

 dried, especially constructed glass cases are generally used. 

 The anthers will dry in bright sunlight in a few hours, or at 

 most in two days. 



267. Storing the pollen. Pollen prepared as indicated 

 may be used for pollinating purposes at once or may be stored 

 and kept for several days or even for a few weeks. Many 

 kinds of pollen may be kept from two to six weeks under 

 favorable conditions, but pollen usually deteriorates after a 

 few days, and the longer it is kept the lower its viability be- 

 comes. There are, however, exceptions to this rule; for 

 example, pollen from the date palm has been kept viable 

 for years. 



In storing pollen it is necessary that it be kept dry in order 

 to prevent molding. A convenient way is to brush the pollen 

 and anthers from the watch glass into a glass vial. Ordina- 

 rily it is well to cork the vials with cotton, although in some. 



