PLANT EVOLUTION 



243 



per cent, with both characters. Those bearing dominant and 

 recessive characters only will breed true, but those bearing both 

 characters will produce offspring in which the characters will 

 continue to reappear in the ratio of 25:50:25. These laws 

 have formed the basis of much very valuable research of the past 



Parent characters. 



/ I > / I \ i i \ \ / ^7 



DDDDDODDaOOnDDDODDD O OO/9 



FIG. 111. Diagram illustrating Mendelism. 



two decades. They demonstrated the value of pedigree cultures 

 in the study of heredity and enabled the experienced worker to 

 predict and interpret results. They explain the reappearance 

 of characters which had apparently been lost in one or more 

 preceding generations. 



These characters are believed to be carried in the chromo- 



