190 



MEMOIRS OF THE NEW YORK BOTANICAL GARDEN 



EXPLANATION OP CHART 4 



As the season advances to more hours of daylight and higher tempera- 

 tures the periods of opening for all varieties tend to shift to earlier clock 

 hours. This is readily seen where one compares the record of this chart 

 with that of February 24, especially noticing the hours for those varie- 

 ties in bloom on both these dates. 



It is quite possible that such variations may have a decided influence 

 in detei*mining the time during the entire season of bloom when the 

 pollinations are most readily made and when they are most effective in 

 fruit-setting. It is to be noted that even as late as March 18, for some of 

 the B varieties (Taft's (xolden, Trapp, and Pollock) the set of first- 

 period flowers open so late in the afternoon that their pollination is diffi- 

 cult for the reasons that at that hour pollen of A varieties is very scarce 

 and that the insects which work during the day are now decidedly 

 inactive. 



