424 BOTANICAL GAZETTE [may 



there will be n groups of i colorless, n/4 groups of 2, n/16 groups 

 of 3, etc.; while, for the colored grains, there will be n groups of 1, 



- groups of 2, ; - groups of 3, etc. The exact values can easily 

 4 10 



be calculated for any ratio, although they frequently must be 

 carried to several decimals. Such a test was applied to numerous 

 types of ratios, and also, for purposes of control, to the tossing of 

 coins (singly or in groups, depending on the ratio). The purpose 

 of the test was to discover whether any of the characters under 

 consideration were determined or limited by local conditions within 

 the ear. Preliminary tests of this sort showed that starchy-sweet 

 and colored-colorless ratios depended only on laws of chance. When 

 the test was applied to the self-colored-mottled ratios of the 

 C tester progeny, the laws of chance were fairly well satisfied, 

 but, undoubtedly, to a less degree than in the other cases. Such 

 slight nonconformity as occurred, however, might well have been 

 accounted for by difficulties in classification. Tests applied to 

 the mottling of the R tester progeny were not thought to be sig- 

 nificant, owing to the very small percentages of the mottled grains 

 appearing. With the particolored grains, however, very decisive 

 results were obtained, indicating clearly that local conditions on 

 the cob affect the appearance of this character. Thus in ears on 

 which less than 10 per cent of the grains were particolored, the 

 majority of the total number of such grains was made up of a few 

 groups of 4 or 5 each. This is particularly interesting, since it has 

 been demonstrated that this condition is heritable. The puzzle 

 will probably be solved by finding that local conditions on the ear 

 do not determine, but merely limit, the appearance of the parti- 

 colored condition. It is expected that some, but not all, of the 

 seemingly quite colorless grains from these ears will perpetuate the 

 particolored tendency. 



Summary 



1. The use of the corn-pollinator is recommended to amateur 

 investigators. 



2. The P(Pr), R, and C factors for aleurone color, variously 

 combined, gave predictable and readily distinguished ratios. 



