80 THE STORY OP THE PLANTS. 



The earliest way is, when a single cell divides in 

 the middle, to form two others; a somewhat less 

 primitive way is when a single cell breaks sud- 

 denly up, and produces from itself a whole 

 swarm of young ones. In both these ways, 

 however, there is no trace of sex ; only one 

 single cell is concerned in the process ; the 

 plants have a mother, perhaps, but certainly not 

 a father. 



The thread-like pond-weeds, however, which 

 are slightly higher plants in the 

 scale of being than the single- 

 ^ celled floating types, show us the 

 first beginnings of something like 

 plant-marriage. These hair-like 

 i little weeds consist each of a single 

 thread or string of cells, placed 

 end on end together, like beads 

 or pearls in a necklet, and con- 

 taining green chlorophyll. You 

 can and them in almost any stag- 

 nant pond in spring, where they 

 FIG. 14.— BEGIN- cling to the side in soft greenish 

 NiNGs OF SEX moss-llkc or velvety masses. But 

 iNAPONDWEED, |f yQ^ examinc one slimy string 



VERY MUCH ^ . "^ , „ .11 



MAGNIFIED. ^^^^^ ^ microscopc, you will 

 see a curious thing often hap- 

 pening between the threads of two such hair-like 

 plants. As they grow side by side, two of the 

 strings will sometimes range themselves just 

 parallel to one another, with their cells facing 

 (Fig. 14). Then each opposite pair of cells 

 begins to bulge a little at the point where they 

 nearly touch [a and b in the figure), till at last 



