ANATOMY OF PLANTS. 211 



these organs, before the more volatile matters can ascend into 

 the parts of fructification. 



It is hence that the nectaries have connnonly such a posi- 

 tion, that the evacuation of the pollen from the antherai is di- 

 rected towards them. This is so evident in the Iridea?, that 

 it is impossible to deny the connection between the nectaries 

 and the organs of fructification. This relation is still more 

 striking, when we observe an inclination of the pistilla, with 

 their stigmata, towards the nectaries, at the period when the 

 former have attained their perfect state. Finally, the evolu- 

 tion of the sexual organs at different times, or what is called 

 the Dichogamy, is a very obvious proof that in many cases 

 fructification is accomplished by the nectaries. When Ave thus 

 observe, that, in the same flo^v er, the antherae are much sooner 

 ripe than the stigmata, or the reverse, it is evident that these 

 latter organs cannot be impregnated by the former, in so far 

 as they belong to the same plant. It hence happens that the 

 first blossoms always fall off, and the fruit fails, when tlie 

 dichogamy is gynandrous, because the early unfolded stigma 

 finds no antherae to impregnate it; and when these become 

 capable of this office, the stigma of these first blossoms has 

 already lost its susceptibility. When the dichogamy is an- 

 drogynous, the last blossoms suffer the same failure, because, 

 when the stigma of the last blossoms has come to perfection, 

 there are no antherae remaining to impregnate it. 



332. 

 From all these considerations it is evident, that there must 

 be some other helps to impregnation ; and this becomes the 

 more obvious, when we observe that tlie sexual organs ai-e often 

 so placed, that, according to any usual and mechanical plan, the 

 fructification cannot happen. We must, no doidjt, ascribe some- 

 thing to the efficacy of the winds, in transporting j)ollen from a 

 distance ; and it is certain, that in the Grasses, and some other 

 plants which have no nectaries, this cause may operate, espe- 

 cially as the antherae of these plants are large and pendant. 

 Insects, also, which suck the honey from the blossoms, are 

 most excellent assistants in impregnation. They wipe off the 



O 9, 



