202 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



following year the trees bore so abundantly that the fruit had to be 

 thinned. In this case, also, an unproductive ranch was converted into a 

 productive one. This was not all, however, for the neighbours also 

 began to feel the benefit and small fruits that were not very profitable 

 began to yield sufficiently to become profitable. 



i: There is another aspect in connection with the fertilization of fruit 

 trees in which bees are indispensable. It is well known that some are 

 self-sterile, and require pollen from another tree brought to them to 

 make them fertile. A tree is self-sterile if it cannot set fruit unless 

 planted near other varieties. An indication of self-sterility is the 

 continued dropping of young fruits, and is generally overcome in 

 California by planting other varieties among the self-sterile ones. 

 Cross-pollination is thus obtained by means of bees or other insects, but, 



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Fig. 72. — Plum ' Black Diamond.' 



as at the time of fruit blossoming there are twenty bees flying to any one 

 other insect, it is evident that cross-pollination is principally dependent 

 on them. Even with fruits that can fertilize themselves it is an 

 advantage to have cross-pollination, as the result is larger and finer 

 fruit." 



From my own experience I can fully endorse all that Mr. Cowan says 

 about the utility of bees to the fruit grower. In the neighbourhood of 

 London and other large towns one often hears the remark that plum and 

 pear trees will not bear fruit because of the smoky atmosphere. It is not 

 the atmosphere so much as the absence of fertilizing insects, especially 

 hive bees, that is the cause of sterility. The trees blossom, and as I 

 have proved by actual experiment, will bear fruit if bees are brought to 

 them while they are in flower. 



It is important, in our uncertain climate, that the bees should be near 

 the fruit trees. In 1907 the spring weather was very uncertain, and 



