Arrangements for Securing Union of Sexes 307 



separate plants, or at least in separate 

 flowers, are comparatively so incon- 

 spicuous that they scarcely are known 

 at all, and need a considerable search to 

 reveal them. The relative conspicuous- 

 ness and abundance of the two kinds of 

 blossoms are typically shown by the 

 Hazel (figure 109). When found, how- 

 ever, these pistils are distinguished b}^ 

 large, and usually branched or hairy, 

 stigmas, — an obvious net spread for the 

 stoppage of the wind-drifted pollen. 

 Thus the "silk" of the Corn, wherein 

 each strand is a style along which grows 

 a pollen-tube to each grain, stands out 

 from the young ears when their grains 

 are ready for fertihzation, as a feathery 

 cluster of styles and stigmas, which 

 catch the pollen carried by wind from 

 the staminate tassels, though later when 

 its usefulness is past, the silk withers 

 limply down. In cases where no stigmas 

 are present, as for example in many 

 cone-bearing plants, like the Spruces and 

 Pines, there is usually some arrangement 

 of smooth scales which guide the inci- 

 dent pollen down to the vicinity of the 

 ovules. Furthermore, it is obvious that 

 the efficiency of wind polhnation de- 

 pends on the greatest possible freedom 

 of wind action through the branches, 

 and therefore on absence of interference 

 by the leaves. This is the reason why 

 so many wind-pollinated flowers open 



Fig. 109. — Flower clusters of the 

 European Hazel, a typical wind 

 pollinated plant, showing the 

 great disproportion in bulk be- 

 tween the male and the female 

 flowers, the former being the 

 long drooping catkins, and 

 the latter the small ovoid- 

 tufted structures. (Copied 

 from Kerner's Pflamenlehen.) 



