246 Introduction to Botany. 



mentioned condition. The direction of the thrust which 

 the bee makes against the retroflexed end of the style is 

 about parallel with its longer straight part. This thrust is 

 intended to lift up the style in a direction about at a right 

 angle with its long axis. Now one who has a conception 

 of mechanics will see that this would not occur so easily if 

 the slender base of the style were straight and its retro- 

 flexed end made a right angle with it. The retroflexed end 

 of the style makes an oblique angle with its long axis, and 

 consequently with the direction of the thrust, for the very 

 same reason that the surface of the wings of a windmill 

 makes an oblique angle with the direction of the wind. And 

 to take a still more pertinent example, which also relates 

 to the crooked base of the style, let one imagine, since the 

 style has a similarity to a crutch, that one were to have a 

 crutch made exactly after the pattern of it. At the very 

 first trial of it he would rue his idea, for should he put his 

 weight upon it the crutch would slip out and he would fall. 

 Finally, why does the membranous appendage of the upper 

 filament lie in part upon the appendages of the two middle 

 ones, and why not the latter or one of them upon the 

 former ? Answer : In order that it may the more easily 

 be pushed up by the bee through the agency of the style. 

 " Now I will relate how I discovered the method of polli- 

 nation of this flower. An observation and an experiment 

 helped me to it in the spring of last year. I saw that the 

 flowers were visited by bees, and I wanted to imitate the 

 effect which they make upon the style ; for I had for a 

 long time conceived that the whole secret must lie behind 

 the form of the style in virtue of which it can so easily be 

 bent upward and afterward falls back again. After many 

 fruitless efforts it finally happily occurred to me to give 

 the plucked flower in this experiment precisely the same 



