Introduction Different Classes 



disappears into the cavity, to be withdrawn 

 backwards covered with pollen. It is pointed out 

 by Muller that the fast closure of the mouth of 

 the Antirrhinum flower is most useful to the 

 plant. Were it otherwise, small bees and other 

 insects would enter the flower and use up the honey, 

 thus withdrawing the attraction which brought 

 about the visits of the larger bees which alone 

 are useful in the accomplishment of cross-fertiliz- 

 ation. These smaller bees are not however 

 always done out of a share of the nectar, because 

 they often bore small round holes at the base of 

 the flower and get access to it in this way. If the 

 visits of bees can be prevented, the flowers at the 

 base of the spike remain longer in condition, and 

 thus a longer spike of bloom is obtained for exhibi- 

 tion purposes. The amateurs in the west of Scotland 

 achieve this by placing an oblong box over the spike, 

 sometimes with a glass front half of the way down, 

 and this prevents bees visiting the flowers. In 

 this connection an interesting scientific fact 

 emerges. Bees visiting spikes of Antirrhinums 

 begin at the bottom flower and work upwards. 

 Transferring their attention to the next spike 

 they carry on their back masses of pollen from 

 the topmost flower of the spike last visited to the 

 bottom flower of the next one, and this pollen 



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