170 HORTICULTURE FOR SCHOOLS 



self-fertile, which self-sterile, and which inter-fertile, and to 

 discover what crosses produce fruit in greatest abundance. 

 This is performed by artificially pollinating the blossoms. 



265. Artificial pollination. In all artificial pollination, the 

 principles taught by nature are utilized. The important 

 points to bear in mind are to secure viable pollen, to insure 

 the application to the stigmas of the kind of pollen desired, 

 to exclude from the stigmas all other pollen, and to keep ac- 

 curate records of the results. 



The operations in artificial pollination are the following: 



1. Procuring, treating, and keeping the pollen. 



2. Preparing the flower for receiving the pollen, and tak- 

 ing steps to prevent pollination by other means than those 

 intended. 



3. Applying the pollen at the proper time. 



4. Keeping the records. 



266. Procuring the pollen. It is not only necessary to 

 secure the pollen, but it is convenient and sometimes im- 

 perative that it be kept for a short time. There are a number 

 of good methods of collecting pollen. In the case of plants 

 which are ordinarily wind-pollinated, as in the chestnut and 

 walnut, all that is necessary is to procure branches on which 

 the anthers have begun to dehisce and place them on news- 

 papers in a dry room, or still better in sunshine under a glass 

 cover such as will keep out wind and insects. In a few hours, 

 or a day or two, an abundance of pollen may be shaken out 

 on the newspapers. If the pistillate flowers of the walnut are 

 to be pollinated at once, it is only necessary to shake a branch 

 having ripe pollen over a branch of the pistillate flowers. 

 To prevent pollination by the wind, it is necessary to place 

 paper bags over the portions of the branches to be pollinated 

 sometime before the stigmas are receptive. The bags are re- 

 moved for the pollinating and are replaced again. 



In the case of ordinary fruit-trees, which depend on insects 

 for pollination, different methods are necessary. It is im- 



