THE WOBK OF FLOWERS 289 



When the pollen is fully formed, the anthers open 

 and allow it to escape. Of what use is the pollen? To 

 answer this question, we may deprive the flower of 

 pollen. For this purpose, choose flowers which are 

 large enough to permit of the necessary manipulation; 

 select unopened buds; carefully open them at the tip, 

 and remove the anthers with a forceps, taking care not 

 to injure the other parts of the flower. The flower is 

 now deprived of all its pollen; but more pollen may be 

 easily brought from neighboring flowers by the wind or 

 by the bees (and other insects), which constantly fly 

 from flower to flower. To prevent this, we may protect 

 the flowers by covering them with small paper bags 

 tied tightly on the stalk, so as to completely enclose 

 the flower. Do flowers so treated form fruit! We 

 must, in every case, have controls which set fruit, 

 in order that we may know whether the experimental 

 conditions are responsible for the lack of it. 



If the pollen is necessary for fruit -making we may 

 next ask. How does it operate? We can see this most 

 clearly if we examine the flower of some Grass or 

 Grain. (Timothy is best for this purpose.) Examining 

 a flower whose anthers have withered, we see what 

 appears to be a tiny brush projecting from the 

 flower. On removing the outer coverings of the 

 flower with needles, we see the ovary (seed -case) with 

 two brush -like styles or stigmas : on examining with 

 a hand -lens we see that they are covered with pollen- 



