BOTANICAL: THE UPPER CLASSES. 



163 



In the Vallisneria, however, the flowers which bear the 

 stamens and those which bear 

 the pistils are always on two 

 separate plants, and unless some 

 means are employed by which 

 the pollen of one can be con- 

 veyed to the other, the family 

 must inevitably perish. 



A curious fact makes the 

 history of this common plant 

 unique in botany. The pisti- 

 liferous branch of the family 

 rises to the surface by a very 

 long and slender spiral stem, 

 floating on the water like a 

 water-lily, while the stameni- 

 ferous branch, growing below, 



remains there, fastened to the Fecundation of a sunflower; 

 soil right down under the 

 water. 



I have told you that, unless 

 the pollen of the stamen is 

 conveyed to the pistil, no seed 



the ovary laid open. 



a, a, walls of the seed-organ ; b, 6, 

 walls of the pistil ; c, c, summit, 



Si? . 



will be produced, and, as the SSPflgS,3&5*F 

 two plants of Vallisneria have 



two localities prescribed for their separate growths, were 

 no means contrived by which the pollen of one could be 

 conveyed to the other, the family would become extinct, 

 for between the flower above and that below roll the 

 intercepting waters of the river. 



It was Vallisnerii, the naturalist, who first discovered 

 the wonders of this plant, and now we have to inquire 

 how the difficulty is met. By a remarkable "coin- 

 cidence" or "acquirement" as some would call it, the 



