ON THE SMALL GRAINS 



inance in the first generation and hence are ex- 

 ceedingly difficult to trace, and yet which reappear 

 segregated in new and varied combinations in the 

 second generation, thus accounting for the extraor- 

 dinary diversity of second generation hybrids to 

 which our attention has been called again and 

 again. 



It is interesting to note that Professor Biff en 

 found such conspicuous conditions as long grain 

 and short grain to fail to manifest the phenomena 

 of dominance and recessiveness. 



Considering that tallness of vine had shown 

 itself to be dominant over shortness of vine in 

 Mendelian peas, it might perhaps have been ex- 

 pected, reasoning from analogy, that long grains 

 of wheat would be dominant to short grains. 



But I have already suggested that it is unwise 

 to attempt to predict the hereditary tendencies of 

 one plant from observation of another; and in 

 particular it should be said that the stems of 

 plants, as regards their fixity of hereditary ten- 

 dency, 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 disturbing 



[67] 



