242 OOLLEGE BOTANY 



series of generations without further cross-pollination, the seeds 

 of each individual plant being always kept separate. The results, 

 very briefly stated, were as follows (Fig. Ill) : In the first gen- 

 eration (known as F^ generation), all the offspring present but 

 one of the two contrasting characters for which the parents were 

 selected. Mendel designated this as the " dominant character " 

 and the character that failed to appear as the " recessive charac- 

 ter." These plants were self-pollinated and the Fj generation 

 grown. In the F^ generation 75 per cent, of the plants presented 

 the same character as the F^ generation (i.e., the dominant 

 character), while 25 per cent present the grandparent character 

 which had failed to appear in the Fj generation (i.e., the reces- 

 sive character) . The 25 per cent, bearing the recessive character 

 present this same character throughout succeeding generations. 

 But if the 75 per cent, of the Fa generation, which bear the domi- 

 nant character, are self-pollinated and the seeds planted, it will 

 be found that one-third of them (i.e., 25 per cent, of the Fg 

 generation) produce the dominant character which will be per- 

 petuated through succeeding generations. But the other two- 

 thirds (i.e., 50 per cent, of the F2 generation) will produce 

 plants with the characters as follows : 25 per cent, dominant, 

 50 per cent, mixed and 25 per cent, recessive. This is illustrated 

 in the diagram (Fig. Ill) in which we will use the square and 

 circle as representing the two characters under consideration. 



Briefly stated, Mendel's Law is as follows: There are two 

 kinds of characters which do not blend but behave as separate 

 units and are known as dominants and recessives. Although 

 these characters do not blend, they reappear in the individuals 

 of successive generations in the ratio of 25 per cent, with domi- 

 nant characters, 25 per cent, with recessive characters and 50 



