CROSS-FERTILIZATION OF FRUIT 343 



While on the subject of bees and fruit it may be in- 

 teresting to add that what applies to all or nearly all 

 Pears applies also to Apples. They are all self -sterile in the 

 seed-sense, but not necessarily in the fruit-sense. It has 

 been stated, however, that some varieties both of Apples 

 and Pears, and notably the important Apple Cox's 

 Orange Pippin, is self-sterile in both senses, and must 

 have the pollen of another variety in order to bear a 

 crop. In such a case as this bees are of particular value, 

 inasmuch as they facilitate the transference of pollen 

 from one variety to another ; indeed, it might almost 

 be said that they are vital if no other variety of Apple is 

 grown near, as without the bees transference of pollen 

 might not take place. In this connection it is pertinent 

 to state that the pollen of Crabs is excellent, and may 

 be more potent than that of cultivated varieties of Apple. 

 The common Crab is good, but so is the Siberian, and the 

 latter is the more ornamental of the two. More beautiful 

 still are the Dartmouth and John Downie Crabs, which 

 are mentioned in another part of this work as worthy 

 of being planted as ornamental trees ; they, too, are 

 good for yielding pollen, and may be planted near Apples, 

 particularly Cox's Orange Pippin, which, as stated above, 

 requires extraneous pollen. Growers should plant a few 

 Crabs among their fruit trees. 



With respect to the pollination of Plums, American, 

 European and Japanese alike, it is found that the varieties 

 differ greatly in the matter of self-fertility, speaking now 

 in the fruit-sense, as in the case of Cox's Orange Pippin 

 Apple. Some will not bear when fertilized with their 

 own pollen, others will do so freely. These facts have 

 been proved by experiments. Transparent paper bags 

 were fixed over selected branchlets bearing fruit-buds 

 before the latter opened, so that foreign pollen could not 



