Mar., 1909.] Removal of Showy Parts of Flowers. 467 



METHOD OF CONDUCTING THE EXPERIMENT. 



This experiment is made up of a series of tests, which will be 

 mentioned separately. By way of explanation when using the 

 term test, test limb or test group, is meant that such a branch 

 or group of blossoms has had the showy parts of the flowers 

 removed, while by a check is meant a branch or group adjoining 

 the test limb or group with blossoms untouched, but simply 

 marked for comparison with the test. 



WEATHER CONDITIONS AS A FACTOR. 



Inasmuch as the weather conditions have been a prominent 

 factor in important developments in this experiment from begin- 

 ning to end, mention will be made of this in the separate tests. 



PART PLAYED BY INSECTS. 



As intimated, in the beginning of the experiment it was 

 thought that insects would perhaps fail to reach those blossoms 

 having the showy parts reinoved as considerable stress has been 

 laid by various observers upon the present high development of 

 flowers as to color and varied form, as due largely if not exclu- 

 sivelv to insect visits. While as before mentioned the experi- 

 ment has had to do with removal of showy parts, it must not be 

 forgotton that these may also be protective. Too much stress 

 has certainly been put upon such development of flowers as due 

 to insect visits, and it will be shown that the visitation of insects of 

 various orders is just as abundant after removal of the showy 

 parts as before. In all of the tests made out of doors in the early 

 part of spring very decided differences in amount of fruit setting 

 was secured in check and test limbs. Thus on some test limbs 

 there would be less than half as much fruit set as on the adjoin- 

 ing check limb on which the blossoms were left untouched. But 

 we would not be justified in saying that this lack of fruit was due 

 to lack of insect visitation when we know that insects were flying 

 and when we see thein on those flowers having the corollas 

 removed. Thus on June 9, observations were made on a syringia 

 bush which was visited quite early in the morning before any 

 insects were flying and a large number of flowers were deprived 

 of corollas. By the time this was finished insects began to come 

 in abundance, among them being the common hive bee, many 

 species of the smaller Apidae, Diptera, and Wasps. The visits 

 were as frequent apparently on the flower with corollas removed 

 as on the blossoms with all the parts. In the afternoon the 

 bush was again visited and found that the flowers with corollas 

 removed were still attracting insect visitors as they were in the 

 early morning hours, the smaller apidae being quite noticeable. 



Some of the more important of the separate tests will now be 

 given somewhat more in detail. 



