54 Fertilization of Plants. [July, 



the use of the pollen as settled much before the time of Linnaeus. 

 Tournefort denied the fertilizing power of the pollen, and con- 

 sidered the stamens simply as organs of excretion. Vaillant, in 

 1716, a pupil of Tournefort, demonstrated the necessity of the 

 pollen in fertilization, and Linnaeus, twenty years after, rendered 

 the idea more universal, that the pollen was the fertilizing mat- 

 ter. For a century the generally received opinion was, that the 

 stamens corresponded to the male organs of generation in ani- 

 mals, and the pistils to the female organs. This is the most pre- 

 valent idea at the present time, although it has met with many 

 powerful opponents. 



Schelver in 1812 advanced the singular idea that the falling of 

 the pollen upon the stigma, so far from impregnating the ovule, 

 only tended to hasten the decay of the surrounding parts, so that 

 the whole force of the plant might be directed to the nourishment 

 and perfection of the ovules already impregnated. 



Turpin, in 1820, promulged the idea that the stamens were 

 only rudimentary pistils, and the grains of pollen rudimentary 

 ovules. These notions found few or no advocates, and they have 

 already received their merited doom. 



Were there any doubts remaining in the minds of botanists on 

 the subject, a work published by Gaertner, in 1844, would en- 

 tirely dissipate all lingering doubts. His numerous and well con- 

 ducted experiments, set at rest this subject of so much interest. 

 The contact of the pollen with the stigma or with the ovules, 

 must take place. 



The arrangements which nature makes for the accomplishment 

 of this result, plainly show its necessity. In the great majority 

 of cases the agents used to bring the pollen to the stigma are the 

 wind, insects, and relative position. Linnaeus remarked that those 

 flowers in which the stamens w^ere shorter than the pistil, were 

 nodding, so that when the anther opened,-the pollen by its gravi- 

 ty would fall upon the stigma, and that those flowers were erect 

 in which the stamens were the longest, so that by the operation of 

 the same force the same end w^ould be accomplished. In cases 

 in which this simple arrangement could not avail, other circum- 

 stances are introduced to bring about these essential phenomena. 



