CONTRIBUTIONS FROM THE WISLEY LABORATORY. 369 



whether he uses pollen of other varieties or not, though he explicitly 

 recommends that this should be done in the case of the White Nectarine, 

 among other fruits.* 



It was not, however, until Waite f published his results that 

 really serious attention began to be given to the matter, and since then 

 this factor has become recognized more and more as an important one 

 in governing the arrangement of the orchard. So far as our present 

 knowledge goes, we know it is advisable to plant varieties flowering 

 at approximately the same time in close proximity to one another 

 so that insects can readily carry pollen from one tree to another. With 

 the object of assisting this the following list made at Wisley has been 

 drawn up. 



It is desirable to point out that we do not yet know with certainty 

 whether better fruit and more of it is produced when some varieties 

 furnish the pollen than when it comes from others, nor do we know 

 whether the comparatively few self-fertile varieties are more fruitful 

 when cross-pollinated. These matters are forming the subject of 

 further investigation at Wisley and elsewhere. 



The following list is based upon observations made in 1908, 1910, 

 1911, 1912, and 1913. The observations were made as a rule on two 

 trees of the variety (one generally on quince, the other on pear stock, 

 but the stock apparently makes little or no difference in the flowering 

 time when the trees have reached a fair age) . The date of full flowering 

 was noted in each case, full flowering meaning that about 50 per cent, 

 of the blossoms were open. The average number of days after 

 the date of full flowering of the earliest variety is given before 

 the name of the variety in the list, the earliest variety being 

 taken as 1. 



As with apples there is no hard and fast order of flowering ; every 

 season sees some alteration in it ; but the list is accurate so far as to 

 show what varieties may be expected to be in flower at about the 

 same time. 



A few flowers on a tree may be open long before the bulk, just as 

 it is no uncommon thing to find a few flowers open long after the rest 

 on a tree. Both cases were well illustrated at Wisley this season, for 

 ' Brockworth Park ' had stray flowers open in mid January and all 

 through the winter and early spring a few flowers could be found, 

 the bulk not opening until April ; while almost every variety bore 

 summer flowers in greater or less profusion. By taking the date of 

 flowering as that at which about half the flowers are open these 

 curious seasonal variations are avoided and a comparison of the 

 effective period of flowering is made possible. 



* Loc. ext. p. 235/ 



| Waite, " Pollination cf Pear Flowers" {U.S.A. Dep. Agr.,Div. Veg. Path., 

 Bull. 5, 1895); 



