10 July, 1917. J Apple Culturt in Victoria. 395 



Plate 109, Fig. 1, is a photograph of clusters of Jonathan pollen 

 grains, which appear white on the black back-ground. Fig. 2 is a 

 drawing of a highly-enlarged vertical section of a pistil division depict- 

 ing the pollen grain (A) in the jaws of the stigma. The position of 

 the sticky fluid, which oozes from the stigma prior to the time of 

 pollination, and which is absorbed by the pollen grain during the 

 period of its germination, is indicated by (B), while (C) shows the 

 jx)lleu tube, after passing down tlie pistil, enlering the micropyle in 

 the ovule. Through this tube the life-giving protoplasm passes from 

 the pollen grain to the ovule, which, by infusion, it fertilizes. 



Sterility In Apple Trees. 



While the admirer of nature's floral decorations is in a state of 

 ecstasy when he beholds an apple orchard in bloom diluting the air 

 with a delicate, pleasing perfume, and adorning the district in which 

 it is situated, its owner is experiencing a most anxious time. 



Although the enterprising and industrious orchardist brings about 

 these pleasing surroundings, he is unable to fully appreciate, in this 

 respect, the result of his labours, because the success or failure of his 

 fruit crop for the year largely depends on the ways of nature during 

 this critical period. The anxiety is considerably alleviated, however, 

 when the orchardist commences and continues to work his trees on 

 scientific lines. In this connexion the careful selection of buds from 

 which to propagate the trees and prevent variety degeneration, the 

 choosing of suitable soil and favorable locality conditions, the insuring 

 of interpollination of sterile or partly sterile varieties by interplanting 

 with others suitable for this purpose, and the maintenance of a few 

 hives of bees in a cosy corner of the orchard, are details, which, of 

 recent times have become ethics in modern horticultural science. 



The officers of the Orchard Supervision Branch have for many 

 years advocated the practice of these essential details, with such a 

 hearty response on the part of the fruit-growers, that at the present 

 time it is difficult to find a young orchard being established in which 

 these remedial measures against sterility are not being employed. 



Sterility in certain varieties of apple trees has become more appa- 

 rent during late years than it was formerly, and the supervisors had 

 frequently to explain the cause of this. The old apple orchard con- 

 tained many varieties, and thus interpollination, in this respect, was 

 unconsciously provided for. But the modern orchard is planted with 

 only a few selected varieties, which may not bloom simultaneously, 

 and it is essential, in order to cross pollinate successfully, that the 

 stigmas of the sterile variety should be in the receptive condition when 

 the pollen of the fertilizer is ripe. 



The chief causes of sterility and " shy " bearing may be summarized 

 as follows : — 



1. Some trees do not blossom freely, and rarely bear fruit, owing 

 to variety degeneration, caused mainly by the propagator having 

 failed to carefully select the buds from which the trees were grown. 



2. The neglect of scientific pruning and the consequent produc- 

 tion of an niincppssarily large quantity of blossom, through which 



