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THE AMEBIC AN NATURALIST [Vol. XLIV 



glumes blackness behaved as a simple Mendelian mono- 

 hybrid, yet in one case there were two definite inde- 

 pendent Mendelian unit characters, each of which was 

 allelomorphic to its absence. Furthermore, in most varie- 

 ties of oats having a ligule, the character behaved as a 

 mono-hybrid dominant to absence of ligule, but in one case 

 no less than four independent characters for presence of 

 ligule, each being dominant to its absence, were found. In 

 wheat a similar phenomenon occurred. Many crosses 

 were made between varieties having red seeds and those 

 having white seeds. In every case but one the F 2 gen- 

 eration gave the ordinary ratio of three red to one white. 

 In the one exception— a very old red variety from the 

 north of Sweden— the ratio in the F 2 generation was 63 

 red to 1 white. The reds of the F 2 generation gave in 

 the F 3 generation a very close approximation to the theo- 

 retical expectation, which is 37 constant red, 8 red and 

 white separating in the ratio of 63:1, 12 red and white 

 separating in the ratio of 15 : 1, 6 red and white separating 

 in the ratio of 3 : 1, and one constant white. He did not 

 happen to obtain the expected constant white, but in the 

 total progeny of 78 F 2 plants his other results are so close 

 to the theoretical calculation that they quite convince one 

 that he was really dealing with three indistinguishable but 

 independent red characters, each allelomorphic to its 

 absence. Nor can the experimental proof of the two 

 colors of the oat glumes be doubted. The evidence of 

 four characters for presence of ligule in the oat is not so 

 conclusive. 



In my own work there is sufficient proof to show that in 

 certain cases the endosperm of maize contains two indis- 

 tinguishable, independent yellow colors, although in most 

 yellow races only one color is present. There is also some 

 evidence that there are three and possibly four inde- 

 pendent red colors in the pericarp, and two colors in the 

 aleurone cells. The colors in the aleurone cells when pure 

 are easily distinguished, but when they are together they 

 grade into each other very gradually. 



