32 INTRODUCTION. 



stone, a lighthouse that resisted the violence of the 

 sea, moulded its contour from the bole of a tree which 

 had withstood the tempests of ages ; and the model was 

 found so admirably adapted to the purpose, that it has 

 been copied, in similar cases, ever since. Even in the 

 more slender plants, that climb upon other plants, or 

 upon walls, the apparatus with which they are fur- 

 nished is the very best adapted for the purpose. They 

 coil round the stem, they lay hold by their spiral ten- 

 drils, or they are covered with little knobs which are 

 the rudiments of roots, that insert themselves into 

 the smallest crevices, and, when once there, so swell 

 and expand, that they break before they can be re- 

 moved. 



The means that they take to secure the succession 

 are equally wonderful in themselves, and in the way in 

 which they harmonize with the rest of creation. The 

 honey that is contained in the nectaries of so many 

 flowers, and which finds so many insects in food, is one 

 certain means of preventing the loss and degeneracy 

 of the plants. The perfecting of the seed depends 

 upon the application to the pistil, or little tube that 

 stands on the rudiment of the seed-vessel, of the pollen, 

 or powder, generally of a yellowish colour, that is con- 

 tained in the anthers, or little knobs upon the top of 

 the filaments. That powder, in many cases, consists 

 of little hollow balls, which are filled with an air or 

 gas, similar to that with which balloons are inflated; 

 and which enables them to float in the air until they 

 alight upon the pistils. Sometimes those two parts 

 are in the same flower, sometimes in different flout is 

 upon the same plant, and sometimes upon different 



