16 LUTHER BURBANK 



plants, as regards their fixity of hereditary tend- 

 ency, are likely to be on a different plane from 

 the flowers or fruit, or any other new characters. 



The particular arrangement of floral envelope 

 that characterizes the plant of to-day is of rela- 

 tively recent development, and may be expected 

 to be subject to greater fluctuations, or, in other 

 words, to show greater plasticity under the dis- 

 turbing influences of hybridization. Professor 

 Biffen even found that there was a difference in 

 the manifestation of dominance and recessive- 

 ness with regard to certain characteristics 

 between different varieties of wheat. 



Thus, in the matter of the glumes, where the 

 parent that bore a felted glume was the variety 

 known as "rough chaff," the felted glume proved 

 dominant over the smooth glume. But where the 

 felted parent was the variety known as rivet 

 wheat, the phenomena of dominance was irregu- 

 larly manifested, or manifested not at all. So 

 hybrids of the rivet wheat were listed in the class 

 of irregular dominants, as above outlined. 



PRACTICAL APPLICATION OF THE NEW 

 KNOWLEDGE 



Having thus analyzed his wheat plants and 

 made himself familiar with their hereditary pos- 

 sibilities, Professor Biffen was ready to make 



