22 THE STORY OF THE PLANTS. 



it is from such insignificant atoms as these that 

 the great forest trees derive their origin, through 

 a long line of ancestors; and if we wish to under- 

 stand the larger and more developed plants, we 

 must begin by understanding these their simple 

 relations. 



Very early plants, then, floated free in water; 

 and there is reason to believe that for a consider- 

 able period in the beginnings of our world there 

 was no dry land at all ; the whole surface of the 

 globe was covered by one boundless ocean. At 

 any rate, most of the simplest and earliest forms 

 of life now remaining to us inhabit the water, 

 either fresh or salt ; while almost all the higher 

 and nobler plants and animals are dwellers on 

 land. Hence it is not unreasonable to conclude 

 that life began i?i the sea, and only gradually spread 

 itself over the islands and continents. 



Floating jelly-like plants would readily reach 

 a size at which it would be convenient for them 

 to split in two — or rather, at which it would be 

 difficult for them to hold together ; and most very 

 small floating plants do to this day continue to 

 grow, up to a certain point, and then divide into 

 two similar and equal portions. This is the sim- 

 plest known form of what we call reproduction. 

 Of course, the two halves into which the plant 

 thus divides itself are exactly like one another; 

 and that gives us the basis for what we call he- 

 redity — that is to say, the general similarity 

 between parent and offspring. This similarity de- 

 pends upon the fact that the two were once one, 

 and when they split or divide each part continues 

 to possess all the qualities of the original mass of 

 which it once formed a portion. 



You will observe that I here use the words, 



