POLLEN, OR FLOWER-DUST 105 



243,000 pollen-grains, each alike beautifully sculp- 

 tured and formed. And again, in the case of a 

 paeony, 3,654,000 grains have been recorded, and 

 as an average for the blossoms of a single rhodo- 

 dendron bush no fewer than 72,620,000 grains 



Fig. 68. Spherical pollen-grains of the vegetable- 

 marrow flower, showing pores 



have been estimated. And, since these numbers 

 apply to flowers fertilised by insects, the enormous 

 totals that would be reached by wind-fertilised 

 plants such as pines, firs, birches, poplars, grasses, 

 &c., are beyond our calculation or even imagina- 

 tion. These wind-fertilised flowers are usually 



