640 MINNESOTA BOTANICAL STUDIES. 



limbs of one and placed it on castrated flowers, which produced 

 fruit. 



Cucumbers were growing beside the tomatoes, and the hum- 

 ble bees preferred the flowers of the latter though occasionally- 

 seen in the cucumber patch. In no instance did I see a bee pass 

 from one kind of plant to the other. A bee working on tomato 

 flowers when disturbed went to another tomato flower, and if 

 driven from the patch, did not stop for other kinds of flowers 

 growing in the vicinity. Red clover was growing along one side 

 of the patch and even this did not tempt a bee that had been 

 working on the tomatoes. Of course the fact that the bees do 

 not pass from one kind of flowers to another helps cross-pollin- 

 ation very materially. 



My seventy five castrated flowers left exposed were not pol- 

 linated by bees for the reason that they do not visit castrated 

 flowers. I purposely castrated part of the flowers of a vine by 

 removing both stamens and corolla, another part by removing 

 the stamens only and left the remaining flowers uncastrated. 

 I found that the bees pay no attention to flowers castrated in 

 the first way, approach those castrated in the second way, but 

 seldom so much as touch them before they find the stamens 

 gone and pass on. 



Tomatoes are seldom, if ever crossed by the wind. If they 

 were, I should certainly have gotten more tomatoes from castra- 

 ted flowers. Mr. C. J. Pennock writes of shaking the pollen off, 

 into a wooden vessel of his own make, to use for pollinating 

 flowers grown in doors in winter. In flowers grown out of 

 doors, the pollen escapes from the pollen sacs as fast as they 

 open; and large amounts of it must blow about as pollen cannot 

 be gathered from garden grown plants in the way described 

 above in any considerable quantity. Some of this pollen in the 

 atmosphere must fall on the stigmas, and I can only account 

 for the fact that fertilization is not effected in this way by sup- 

 posing that more pollen is required to produce fruit than 

 finds its way to the stigma by being blown about in the air. 



Experiments were carried on to find the causes of one sided 

 fruit. Tomatoes with this defect noticeable are not common on 

 garden-grown vines except in those which develop from mon- 

 strous flowers, though Prof. L. H. Bailey finds it quite common 

 in winter-grown fruit. Suspecting the cause to be that the pol- 

 len is not deposited on all parts of the stigma, I tried cutting 

 off one side. The result is usually a one-sided tomato, but not 

 always. Later I got fruit in about one case in ten where I had 



