Reproduction 



351 



is the mere dusting of the stigmatic surfaces with pollen. 

 This pollen may be derived from the anthers of the same 

 blossom, from different flowers, individuals, or species. 



N * \ 



FIG. 95. Flowers of date-palm : staminate cluster (A) and blossoms (a) ; 

 pistillate cluster (B) and blossoms (6) . [After Swingle.] 



If such pollen-grains do not germinate, or if no germ-tubes 

 penetrate the stigma, they may awaken no more response 

 than so much dust. If we may acknowledge faith in the 

 current belief regarding pollen as a factor in " hay fever," 



