FERTILIZATION. 109 



thousand years. The Baobab trees of Africa, and the Dragon 

 tree of Orotava, are said to be even six thousand years old. 

 Pliny believes there were trees in his time as old as the world, 

 as he says they were " in facta cevis et congenita mundo, un- 

 touched by age and brought forth with the world." 



Means have been devised for the determining the ages of 

 trees by the diameters, but they are so liable to error, that they 

 are unworthy of repetition. 



CHAPTER V. 

 Section 1. — Fertilization. 



193. The subject of fertilization is one of much interest, 

 from the singularity of the operations by which it is in some 

 cases carried on, and the beautiful adaptation of the means to 

 bring about this indispensable end. 



All plants possess some apparatus for the production of seed, 

 or of bodies which, independent of the parent, will vegetate and 

 produce the species ; from the most simple Conferva?, with stems 

 scarcely larger than films of silk, to the most perfect plants. 

 The fact that some plants possessed two systems by whose con- 

 joined action the fruit and seed were perfected, has been long 

 known. The ancients were acquainted with this fact in refer- 

 ence to the Date Palm. They discerned that in the blossom of 

 one tree, rudiments of fruit existed, while in that of others no 

 such rudimentary fruit was produced, but that the powder pro- 

 duced by the flower of the latter must be sprinkled in the 

 flowers of the other, in order to the perfection of the fruit. The 

 above and similar facts constituted all the knowledge of the 

 ancients on the subject of fertilization ; and it was not till the 

 latter part of the seventeenth century that any thing like proper 

 notions began to prevail. Ray, in England, and Malpighi, in 

 Italy, were among the first who placed the subject in its true 

 light. Their in resti nations led them to the conclusion that the 

 " pollen was endowed with prolific power, and served to fertilize 

 the seeds." 



Within the last few years this subject has received the partic- 

 ular attention of the most distinguished philosophers, and the 



193. What do all plants possess ? "What has been long known ? What 

 30nclusion did Kay and Malpighi come to ? 



