316 SEXUALITY OF VEGETABLES. CHAP. VI. 



persion, at least to any pistil that is near it, and at 

 such a time as pistils of the same species are best 

 fitted to receive it. When the anther has given in- 

 dications of maturity by the distended appearance 

 of its cells ; the valves of which the cells consist 

 become daily more and more indurated till at last 

 they fly open with a sudden jerk, and discharge the 

 contained pollen as if by the force of an elastic 

 spring. The phenomenon exhibited in this case by 

 the Cypress-tree affords a good example, in which 

 the pollen is thrown out with such force and in 

 such abundance as to resemble a little cloud of 

 smoke ; but the same phenomenon may be observed 

 in the discharge of the pollen from the male catkins 

 of the Birch arjd Willow, particularly if they 

 arc suddenly shaken or agitated by the wind ; in 

 which cases a portion of the pollen can scarcely 

 fail to alight upon the pistil-bearing and contiguous 

 flowers, or to be wafted to them if even at some 

 distance. 



But at the season of the discharge of the mature 

 pollen, the pistil is also peculiarly adapted to re- 

 ceive it, as is evident from the state of the stigma. 

 Sometimes this adaptation consists in the stigma's 

 then assuming a peculiar form or shape, as may be 

 exemplified in the case of the Gratiola, Martynia, 

 and Viola tricolor or Pansy, all of which are fur- 

 nished with what botanists call a gaping stigjna, 

 opening as if to receive the pollen, yet not in the 

 early stage of its growth, nor during its decline ; but 



