150 



On Flowers and Insects. 



plant to be spared from the effort of their produc- 

 tion. 



4. As the type of another class of cases in which 

 two kinds of flowers are produced by the same 

 species (though not on the same stock), we may 

 take our common Cowslips and Primroses. If you 



Fig. 52. COMMON COWSLIP (Primula veris). 



examine a number of them, you will find that they 

 fall into two distinct series. In some of the flowers 

 the pistil is as long as the tube, and the button- 

 shaped stigma (fig. 53, st) is situated at the mouth 

 of the flower, the stamens (a a) being halfway down 

 the tube ; while, in the other flowers (fig. 54), on the 

 contrary, the anthers are at the mouth of the flower, 

 and the stigma halfway down. The existence of 



