51 



Keeping in mind the relative size of a stigma and one or 

 these glass plates one can readily see that if the fruit crop 

 depended upon cross-pollination by the wind the chances for 

 a bumper crop would be remote indeed. 



Still another experiment tried out by Prof. Lewis shows 

 rather significant results. A seven year old tree having 

 1500 blossoms stood about 20 ft. from trees in heavy bloom. 

 The flowers of this young tree were emasculated (i. e. all 

 floral parts, except pistils "^ere removed.) The result was 

 that five fruits set on the tree. A watch was kept on the 

 tree to see if insects visited it. During the time when the 

 pistils were receptive eight bees visited the tree, while more 

 than twice that number were seen in a half hour on another 

 tree 20 feet distant. 



Scientists have long pointed out the fact that those 

 plants which depend upon the wind to bring about cross- 

 pollination are as a rule distinguished by having an abun- 

 dance of powdery pollen, by the absence of nectar glands and 

 also by having flowers that are not showy. While on the 

 other hand those plants that depend upon insects to bring 

 about cross-pollination are characterized by having showy 

 flowers, nectar glands and sticky or doughy pollen. Also 

 many of these flowers emit a perfume. Whatever value, if 

 any, may be attached to this generalized statement it- is 

 curious to note that the plants under discussion, the orchard 

 fruits, without exception belong to the last named class, 



INSECTS AS POLLINIZERS 



The foregoing experiments indicate quite clearly that 

 the wind cannot be depended upon to bring about cross- 

 pollination of our orchard fruits, consequently with its 

 elimination it necessarily follows that this important work 

 must be done by the insects found in our orchards at bloom- 

 ing time. 



Prof. Waugh kept a record of the various insects seen 

 visiting the plum blossoms. In 1898 twenty-eight species 

 were counted ; of these eighteen species were Hymenoptura 

 or bees. In 1899 there were sixteen species of which seven 

 were bees or their allies and nine species of flies. While no 

 actual figures are given the general statement is made that 

 of all the species the honey-bee is by far the most important. 



