THE FL O WER PER TILIZA TION AND POLLINA TION 1 49 



the envelopes are pushed downward and outward and 

 the pistil and stamens come in contact with its abdomen. 

 Since the flower is proterandrous, the 

 pollen that the pistils receive from the 

 bee's abdomen must come from another 

 flower. Note a somewhat similar ar- 

 rangement in the toadflax or butter-and- 

 eggs. - 



In some cases (Fig. 203) the stamens 

 are longer than the pistil in one flower 

 and shorter in another. If the insect 

 visits such flowers, it gets pollen on its 

 head from the long-stamen flower, and 

 deposits this pollen on the stigma in the 

 long-pistil flower. Such flowers are di- 

 morphous (of two forms). If pollen from its own flower 

 and from another flower both fall on the stigma, the proba- 

 bilities are that the stigma will choose the foreign pollen. 



FIG. 202. STAMENS 

 OF LARKSPUR, sur- 

 rounding the pistils. 



FIG. 203. DIMORPHIC FLOWERS OF PRIMROSE. 



Many flo ivers are pollinated by the wind. They are said 

 to be anemophilous ("wind loving "). Such flowers pro- 



