POLLEN-FLOWERS 



Fig. 97. Common Loosestrife. Steironema ciliatum 



A pollen-flower 



trefoils and lupines in the pulse family, in families where the 

 majority of the genera yield nectar, admits of hardly any other 

 explanation. There is httle difficulty in understanding how a 

 flower may lose the power of secreting nectar. Flowers from 

 which the bee-keeper in one region derives an enormous sur- 



201 



