Some Apparent Exceptions 93 



character. It was found at the Swedish Experi- 

 ment Station at Svalov, previously mentioned, 

 that when two wheat plants were crossed, one 

 of which had kernels that were brown coated, 

 the other white coated, the expected Mendelian 

 ratio of 3 to I in the F^ generation did not 

 appear, but the brown-coated kernels were 

 fifteen times as numerous as the white-coated, 

 and were of several shades of brown. The 

 ratio 15 to I evidently suggests that two factors 

 are involved, but the customary grouping 

 9-3-3-1 is changed, so that the first three terms 

 are united in a single term. Nilsson, Director 

 of the Swedish Station, supposes that there are 

 two factors present, either of which produces 

 brown (see checkerboard). Both are present in 

 double dose in the offspring in the F^ generation, 

 in one case out of the 16, and the brown color is 

 very deep. One is present in double dose, the 

 other in single dose in 4 cases, and the brown 

 color is less pronounced. Only one is present 

 either in double dose or single dose in 6 cases, 

 and the brown color is still paler. Neither is 

 present in one case, the white. In another 



