F. J. ClIITTKNDEN 41 



and this is an economical method of planting an orchard, since the same 

 operations can be carried out simultaneously over a considerable and 

 consecutive area. On the other hand, with self-sterile varieties, the 

 knowledge of what varieties to interplant is important. It is quite 

 certain that, until we have much more light on the causes of self-sterility, 

 it will not be possible to give the authoritative advice for which the 

 grower is entitled to look. 



We are experimenting in the gardens of the Royal Horticultural 

 Society, with the object of ascertaining what varieties of apple and pear 

 are fertile inter se, and are carrying out other lines of work on the matter, 

 and have just put up a large orchard house for extending our work, 

 but, as we have indicated, observations in other localities upon particular 

 points are of the utmost importance, in order that some of the questions 

 at issue may be solved. The wish to bring this very important matter 

 before the notice of those who may have the opportunity of carrying 

 out some work upon it, is one of my objects in writing this note. 



Certain points are, of course, clear, and the plainest is that varieties 

 flowering at approximately the same time should be planted together. 

 We have given, in the Journal of the Royal Horticultural Society, lists 

 of varieties of apples and pears, in their relative orders of flowering, 

 with the object of guiding the planter on this particular point, and we 

 have there compared our own average dates of flowering with those of 

 the same varieties in other parts of the world. These comparisons make 

 it clear that approximately the same order of flowering is maintained 

 by the different varieties all over the world, no matter what the climate 

 may be, so that a list founded, upon the average for several years, drawn 

 up in one locaHty, will prove a reliable guide in any other fruit-growing 

 district. 



Another point of economic importance lies in the relative size of 

 fruits produced by the aid of foreign pollen and without it. They are, 

 as a rule, larger when seeds are produced, and are reputed to be sweeter. 



The Carrying of the Pollen. There remains another point of general 

 interest : How is the pollen carried ? The suspension of glass slips 

 smeared with glycerine a few feet on the leeward side of blossoming 

 apples and pears, has resulted in the capture of a very small amount of 

 pollen, in marked contrast to the amount of pine pollen which we have so 

 collected from pine trees as much as a quarter of a mile distant. 



A large number of rather desultory observations have been published 

 regarding the insects which effect inter-pollination in the apple and pear, 

 and it is certain that insects are the chief agents. But some have claimed 



