ON PEAS AND BEANS 



(7) The length of the stem of the plant itself, 

 whether tall or dwarfish. 



It is obvious that in each case the different 

 qualities named are antagonistic or mutually ex- 

 clusive. The seed cannot be at the same time 

 round and angular; it cannot be at the same time 

 smooth and wrinkled; cotyledons cannot be at 

 once yellow and green; the pods cannot be at once 

 inflated and constricted. And as each race of peas, 

 when inbred, holds true to its type, there was 

 opportunity to observe the effects of crossing the 

 different races in relation to these different fixed 

 characters. 



The results Mendel obtained have already been 

 outlined, and more than once referred to in this 

 and in previous volumes. 



It will be recalled that, as regards the various 

 pairs of antagonistic characters, he found that one 

 or the other proved prepotent or dominant in the 

 first generation; but that in the second generation 

 (when the first generation hybrids were inbred) 

 the submerged or recessive character would reap- 

 pear in one case in four on the average. Thus he 

 found that in the pea tallness of stalk is dominant 

 to shortness of stalk; that yellowness of seed is 

 dominant to greenness of seed, etc. 



This was demonstrated by the fact when a tall 

 pea was crossed with a short one all the offspring 



[89] 



