170 Field, Forest, and Wayside Flowers 



As grass-pollen is carried about among the blos- 

 soms by the wind much of it is liable to be 

 dropped and wasted. 



FIG. 43. Sand-bur grass (Ctnchms tribiiloides). 



a and 3, the bur ready to travel ; r, the pair of flowers, i staminate and i perfect. 

 (From Bulletin No. 7 of the U. S. Department of Agriculture, ''American 

 Grasses.") 



In some species Nature makes good this loss 

 beforehand by furnishing a double supply of the 

 life giving grains. 



