4i6 



GENERAL PRINCIPLES 



corolla near the opening of the funnel. Each anther is at- 

 tached to the upper end of a long lever, which is pivoted in the 

 middle. When an insect enters the flower it brushes against 

 the lower end of this lever, causing it to rise, and the opposite 

 end with the anther comes down on the insect's back, leaving 



Fig. 254. — Diagram to explain the preceding figure. The bee ahghts on the 

 spreading lobe of the perianth (s) and forces his way under the stigmatic shelf 

 (/) and the anther (an). In doing so some of the pollen left on his back from a 

 flower previously visited, is scraped off by the stigma and then he is immediately 

 dusted with pollen again by contact with the anther. The nectary is shown 

 at n. 



a dab of pollen upon it. At this time the stigma is high up 

 under the hood-like edge of the corolla, but later it grows out 

 and down so that it assumes approximately the place where the 

 anther strikes the insect. When now a bee which has previously 

 been dusted with pollen visits this flower the stigma brushes 

 against its body and is pollinated. 



