56 



THE POLLINATTON OF PEAR FLOWERS. 



Ill fact in all the Rosaceie, which family includes the majority of orchard 

 and small fruits, the question is still in dispute. Attention lias 

 already been called to the fact that the principal part of a pear or apple 

 is a development of organs outside and surrounding the ovary. So it 

 might be more difficult for the effect of pollen to reach and influence 

 such organs than it would the seed or ovary walls. 



IS'early one hundred years ago Knight decided, after applying pollen 

 of widely difiterent varieties, tliat in the pear and apple no change 

 whatever was effected. Long before Knight's time observers had noted 

 differences supposed to be caused by pollen. In recent years this sub- 

 ject has been investigated in our own country. At the Michigan Agri- 

 cultural College, Charles W. Garfield found in case of api^les differ- 

 ences in flavor, color, and shape, which he attributed to the difference 

 in xDollen, but recently he is said to have expressed doubt as to whether 

 the i3ollen brought about the difference. At the same place Prof. L. 

 H. Bailey, after making a large number of crosses, decided that no 

 effect was produced by the difference in pollen. In 1888 A. A. Crozier* 

 exx^erimented in the same line and a large number of crossed apples 

 were studied by him. He says: ^'The examination failed to show any 

 diflerences which could be attributed to the influenc^e of the cross. In 

 several instances different varieties were crossed on the same tree, but 

 the resulting fruits did not difler materially from each other or from 

 the remainder of the crop on the tree." It will be evident from the 

 study of cross and self-pollinated fruits which follows that the whole 

 matter must be viewed in a new light. 



Explanation of Tables. 



The results of the examination of the fruits are printed in the tables 

 which follow. The first column contains the record number, which 

 refers back to the bag in the experiments on the flowers, and as the 

 same numbers occur in the synopsis the reader can there find further 

 facts about the tree. These numbers also occur in the x)lates. The 

 secoiid column gives the weight in grams. This was considered the 

 most convenient w^ay of determining the size of the fruit. Quality is 

 supposed to include flavor and texture. The other headings will 

 explain themselves. The differences in the fruits were often too 

 slight to describe in the tables, so a fcAv remarks underneath were 

 necessary to point them out. The seeds are of course botanically a 

 part of the fruit, but for our purpose they are considered as distinct 

 from the fleshy part. A pear has normally ten ovules and usually ten 

 seeds. If five are developed into perfect seeds then five remain abor- 

 tive. The abortive seeds are of little consequence. The main atten- 

 tion- should be devoted to the sound seeds. It is even a question 

 whether these abortive seeds have been fecundated at all. In the pear 



*Iowa Agr. Exp. Sta. Bull. No. 3, 1892. 



